ZIRCONIA-TOUGHENED GLASS CERAMICS

Information

  • Patent Application
  • 20190177210
  • Publication Number
    20190177210
  • Date Filed
    June 26, 2017
    7 years ago
  • Date Published
    June 13, 2019
    5 years ago
Abstract
ZrO2-toughened glass ceramics having high molar fractions of tetragonal ZrO2 and fracture toughness value of greater than 2 MPa·m1/2. The glass ceramic may also include also contain other secondary phases that may be beneficial for toughening or for strengthening through an ion exchange process. Additional second phases may also decrease the coefficient of thermal expansion of the glass ceramic. A method of making such glass ceramics is also provided.
Description
FIELD OF DISCLOSURE

The disclosure relates to glasses and glass ceramics. More particularly, the disclosure relates to tetragonal zirconia-containing glass ceramics, along with the glasses that form these glass ceramics. Even more particularly, the disclosure relates to tetragonal zirconia-containing glass ceramics having high fracture toughness.


BACKGROUND

Transformation-toughened ZrO2 ceramics are among the toughest and strongest of the engineering ceramics, and are typically produced via ceramic processing techniques such as hot pressing or sintering. In another approach, prefabricated ZrO2 particles are dispersed in a matrix of either ceramic or glass. In this case, the ZrO2 fraction of the final product is substantially lower than that of the pure ceramic material. Generally, these ceramics are monolithic-stabilized oxides, such as Ca, Mg, Ce or yttria-stabilized ZrO2, where the principal phase of the monolith is ZrO2.


In order to realize transformation toughening, it is necessary to obtain the tetragonal form of ZrO2 in the as-made part. The tetragonal ZrO2 phase transforms to the monoclinic phase under mechanical stress, which leads to toughening. However, ZrO2 undergoes a thermal transition from tetragonal to monoclinic symmetry or structure at about 950° C. This can occur during processing of the materials, producing a material comprising the “transformed” monoclinic form. Presence of the monoclinic form in the as-made material does not offer the opportunity for subsequent transformation toughening.


SUMMARY

The present disclosure provides ZrO2-toughened glass ceramics having high molar fractions (mass fractions) of tetragonal ZrO2 and a fracture toughness of greater than 2 MPa·m1/2. The glass ceramic may also include other secondary phases that may be beneficial for toughening or for strengthening. In some embodiments, strengthening may be achieved through an ion exchange process. Additional phases may also impart other properties or performance in the glass ceramic, such as decrease or increase in the coefficient of thermal expansion of the glass ceramic. A method of making such glass ceramics is also provided.


Accordingly, one aspect of the disclosure is to provide a precursor comprising at least about 20 mol % Li2O, up to about 5 mol % Al2O3, at least about 50 mol % SiO2 and at least about 3 mol % ZrO2. When the precursor glass contains Al2O3, the glass-ceramic formed from such precursor glass may also contain lithium alumosilicate crystalline phases such as β-quartz-solid-solution and β-spodumene.


One aspect of the disclosure is to provide a glass ceramic comprising at least about 20 mol % Li2O, up to about 5 mol % Al2O3, at least about 50 mol % SiO2 and at least about 3 wt % ZrO2. When the precursor glass contains Al2O3, the glass-ceramic formed from such precursor glass may also contain lithium alumosilicate crystalline phases such as β-quartz-solid-solution and β-spodumene


Another aspect of the disclosure is to provide a glass ceramic comprising a tetragonal ZrO2 phase, a crystalline lithium disilicate phase, and a residual glass phase. The glass ceramic comprises: from about 50 mol % to about 75 mol % SiO2, from 0 mol % to about 5 mol % Al2O3; from about 18 mol % to about 40 mol % Li2O; from 0 mol % to about 5 mol % Na2O; from 0 mol % to about 5 mol % of at least one alkaline earth oxide; from 0 mol % to about 5 mol % of at least one rare earth oxide; and from about 4 mol % to about 15 mol % ZrO2.


Another aspect of the disclosure is to provide a glass ceramic comprising a tetragonal ZrO2 phase, a crystalline lithium disilicate phase, optionally a lithium alumosilicate phase and a residual glass phase, wherein the glass ceramic has a fracture toughness of at least about 2 MPa·m1/2. The glass ceramic comprises: from about 50 mol % to about 75 mol % SiO2; from 0 mol % to about 5 mol % Al2O3; from about 18 mol % to about 40 mol % Li2O; from 0 mol % to about 5 mol % Na2O; from 0 mol % to about 5 mol % of at least one alkaline earth oxide; from 0 mol % to about 5 mol % of at least one rare earth oxide; and from about 4 mol % to about 15 mol % ZrO2.


Another aspect of the disclosure is to provide a method of making a glass ceramic, the glass ceramic comprising a tetragonal ZrO2 phase, a crystalline lithium disilicate phase, and a residual glass phase. The method comprises: providing a precursor material, the precursor material comprising at least about 18 mol % Li2O, up to about 5 mol % Al2O3, at least about 50 mol % SiO2 and at least about 4 mol % ZrO2; and ceramming the precursor material to form the glass ceramic, wherein ceramming comprises heating the precursor material at a first temperature for a first time period, followed by heating at a second temperature for a second time period, wherein the first temperature is in a range from about 450° C. to about 750° C., the first time period is in a range from about 10 minutes to about 2.5 hours, the second temperature is in a range from about 800° C. to about 1125° C., and the second time period is in a range from about 0.5 hour to about 5 hours. The first heat treatment may result in annealing and/or nucleation.


Another aspect of the disclosure is to provide glass ceramics produced by the process(es) described herein.


These and other aspects, advantages, and salient features will become apparent from the following detailed description, the accompanying drawings, and the appended claims.





BRIEF DESCRIPTION OF THE DRAWINGS

Referring to the drawings in general, it will be understood that the illustrations are for the purpose of describing particular embodiments and are not intended to limit the disclosure or appended claims thereto. The drawings are not necessarily to scale, and certain features and certain views of the drawings may be shown exaggerated in scale or in schematic in the interest of clarity and conciseness.



FIG. 1A is a scanning electron microscopy (SEM) image of a glass ceramic material that was cerammed by heating at 750° C. for 2 hours and then heating at 900° C. for 4 hours;



FIG. 1B is a SEM image of a glass ceramic material that was cerammed by heating at 800° C. for 2 hours and then heating at 900° C. for 4 hours;



FIGS. 2A-D are SEM images of an area indented using a Vickers indenter with force on the surface of a glass ceramic that was cerammed by heating at 700° C. for 2 hours and then heating at 900° C. for 4 hours;



FIG. 3 a plot of ring-on-ring data obtained for 1 mm-thick samples of a ZrO2-toughened glass ceramic, which was cerammed by heating at 700° C. for 2 hours and then by heating at 850° C. for 4 hours, and a β-spodumene glass-ceramic.



FIG. 4 a plot of abraded and non-abraded ring-on-ring (ROR) data obtained for 1 mm-thick samples of ion-exchanged ZrO2-toughened glass ceramic, which was cerammed by heating at 700° C. for 2 hours and then heating at 850° C. for 4 hours, with and without ion-exchange, and analogous data for β-spodumene glass-ceramic.



FIG. 5 XRD pattern of Example 6 (Table 2) after crystallization heat treatment for 1 h at 840° C.



FIG. 6 SEM Micrograph (backsacttered electrons) of Example 6 (Table 2) after crystallization heat treatment for 1 h at 840° C. Surface of the sample was polished and subsequently etched with vapor of 40% HF acid for 30 s.



FIG. 7 SEM Micrograph (backsacttered electrons) of Example 6 (Table 2) after crystallization heat treatment for 1 h at 840° C. Surface of the sample was polished. Dark lath-like textures represent Li2Si2O5 crystals.



FIG. 8 XRD pattern of Example 3 (Table 2) after crystallization heat treatment for 1 h at 880° C.



FIGS. 9A and 9B SEM Micrographs at two different magnifications (secondary electrons) of Example 3 (Table 2) after crystallization heat treatment for 1 h at 880° C. Surface of the sample was polished and subsequently etched with vapor of 40% HF acid for 30s. Dark lath-like textures represent Li2Si2O5 crystals.



FIGS. 10A and 10B SEM Micrograph at two different magnifications (backsacttered electrons) of Example 1 (Table 2) after crystallization heat treatment for 48 h at 820° C. Surface of the sample was polished and etched for 30 s with 40% HF vapor. Dark lath-like textures represent Li2Si2O5 crystals. Bright white textures represent crystalline ZrO2.





DETAILED DESCRIPTION

In the following description, like reference characters designate like or corresponding parts throughout the several views shown in the figures. It is also understood that, unless otherwise specified, terms such as “top,” “bottom,” “outward,” “inward,” and the like are words of convenience and are not to be construed as limiting terms. In addition, whenever a group is described as comprising at least one of a group of elements and combinations thereof, it is understood that the group may comprise, consist essentially of, or consist of any number of those elements recited, either individually or in combination with each other. Similarly, whenever a group is described as consisting of at least one of a group of elements or combinations thereof, it is understood that the group may consist of any number of those elements recited, either individually or in combination with each other. Unless otherwise specified, a range of values, when recited, includes both the upper and lower limits of the range as well as any ranges there between. As used herein, the indefinite articles “a,” “an,” and the corresponding definite article “the” mean “at least one” or “one or more,” unless otherwise specified. It also is understood that the various features disclosed in the specification and the drawings can be used in any and all combinations.


Where a range of numerical values is recited herein, comprising upper and lower values, unless otherwise stated in specific circumstances, the range is intended to include the endpoints thereof, and all integers and fractions within the range. It is not intended that the scope of the claims be limited to the specific values recited when defining a range. Further, when an amount, concentration, or other value or parameter is given as a range, one or more preferred ranges or a list of upper preferable values and lower preferable values, this is to be understood as specifically disclosing all ranges formed from any pair of any upper range limit or preferred value and any lower range limit or preferred value, regardless of whether such pairs are separately disclosed. Finally, when the term “about” is used in describing a value or an end-point of a range, the disclosure should be understood to include the specific value or end-point referred to. When a numerical value or end-point of a range does not recite “about,” the numerical value or end-point of a range is intended to include two embodiments: one modified by “about,” and one not modified by “about.”


As used herein, the term “about” means that amounts, sizes, formulations, parameters, and other quantities and characteristics are not and need not be exact, but may be approximate and/or larger or smaller, as desired, reflecting tolerances, conversion factors, rounding off, measurement error and the like, and other factors known to those of skill in the art. It is noted that the terms “substantially” may be utilized herein to represent the inherent degree of uncertainty that may be attributed to any quantitative comparison, value, measurement, or other representation. These terms are also utilized herein to represent the degree by which a quantitative representation may vary from a stated reference without resulting in a change in the basic function of the subject matter at issue. Thus, a glass that is “free of Al2O3” is one in which Al2O3 is not actively added or batched into the glass, but may be present in very small amounts as a contaminant (e.g., 500, 400, 300, 200, or 100 parts per million (ppm) or less or).


Unless otherwise specified, all compositions are expressed in terms of mole percent (mol %). Compositional ranges of crystalline materials in the glass ceramic are expressed in terms of weight percent (wt %) is many instances, but ceramic volume percent (vol %) is also used in some instances to quantify the amount of crystalline phase content in a glass ceramic material. Coefficients of thermal expansion (CTE) are expressed in terms of 10−7/° C. and represent a value measured over a temperature range from about 20° C. to about 300° C., unless otherwise specified. The density in terms of grams/cm3 was measured via the Archimedes method (ASTM C693).


Vickers crack initiation thresholds described herein are determined by applying and then removing an indentation load to the glass surface at a rate of 0.2 mm/min. The indenter uses a standard 136° tip angle on a diamond indenter. The maximum indentation load is held for 10 seconds. The indentation cracking threshold is defined at the indentation load at which 50% of 10 indents exhibit at least one radial/median crack emanating from the corners of the indent impression. The maximum load is increased until the threshold is met for a given glass ceramic and/or the precursor glass. All indentation measurements are performed at room temperature in 50% relative humidity.


Fracture toughness values described herein may be as measured by chevron notch short bar methods known in the art and described in ASTM procedure E1304-97 (2014), entitled “Standard Test Method for Plane-Strain (Chevron-Notch) Fracture Toughness of Metallic Materials.” The contents of ASTM E1304-97 (2014) are incorporated herein by reference in their entirety. The test method involves application of a load to the mouth of a chevron-notched specimen to induce an opening displacement of the specimen mouth. Fracture toughness measured according to this method is relative to a slowly advancing steady-state crack initiated at a chevron notch and propagating in a chevron-shaped ligament.


Fracture toughness values can also be measured using the Single-Edge V-Notched Beam method (SEVNB) method as described in the ISO for dental ceramics ISO 6872 2015.


Glass Ceramics and Glass Ceramic Precursors

When a glass is converted into a glass-ceramic, portions of the glass crystallize while other portions may remain in a residual glass phase (e.g., amorphous, non-crystalline). As used herein, the term “glass ceramic” refers to a material comprising at least one crystalline phase and a residual glass phase. In some embodiments, a glass ceramic is a material comprising at least 50%, 60%, 70%, 75%, 80%, 85%, 90%, 95%, 97%, 98%, 99% or greater than 99% wt % of at least one crystalline phase, with the remaining wt % comprising a glass phase. The terms “glass ceramic article” and “glass ceramic articles” are used in their broadest sense to include any object made wholly or partly of glass ceramic. The terms “ceram” and “ceramming,” as used herein, refer to a heat treatment (or heat treatments) or other process(es) used to convert a precursor glass into a glass ceramic.


The glass ceramics described herein comprise crystalline structures that can be understood via crystallography and known crystal systems. As used herein the terms “tetragonal ZrO2,” “tetragonal zirconia,” and “t-ZrO2” are used interchangeably and refer to crystalline ZrO2 having a tetragonal crystal system; the terms “monoclinic ZrO2,” “monoclinic zirconia,” and “m-ZrO2” are used interchangeably and refer to crystalline ZrO2 having a monoclinic crystal system; and the terms “cubic ZrO2” and “cubic zirconia” and “c-ZrO2” are used interchangeably and refer to crystalline ZrO2 having a cubic crystal system as understood in chemical crystallography. Additional crystalline structures may be present in the precursor glass or glass ceramic phases of the materials. For example, lithium disilicate glass ceramic phases may have orthorhombic or other crystal systems.


A first aspect comprises zirconia-containing precursor glasses and glass ceramics made from the precursor glasses. The glass ceramics made from these zirconia-containing precursor glasses are zirconia-toughened glass ceramics having high volume fractions of tetragonal ZrO2, which can be 1 to 20 wt %. During the making of the precursor glass ZrO2 is capable of being dissolved in a large amount (generally, greater than about 10 wt %) without crystallizing upon cooling from the glass pour. Lithium and/or magnesium silicate melts with relatively low alumina contents generally have high ZrO2 solubility. When the precursor glass is subjected to a prescribed heat treatment, dissolved ZrO2 is crystallized and precipitated out primarily as the tetragonal ZrO2 phase with, in some embodiments, less than 5 wt % monoclinic ZrO2 relative to the total ZrO2.


The glass ceramics described herein comprise a tetragonal ZrO2 phase, a crystalline lithium disilicate (Li2Si2O5) phase and a residual glass phase. The tetragonal ZrO2 phase, in some embodiments, may make up all (>70 wt %, >80 wt %, >90 wt %, >93 wt %, >95 wt %, >97 wt %, >99 wt %) the ZrO2 present in the glass ceramic. In some embodiments, the tetragonal ZrO2 phase may make up 5-17 wt % of the total glass ceramic composition. In some embodiments, the tetragonal ZrO2 phase may make up 5-60 wt % of the total crystalline phase of the glass ceramic (([weight tetragonal ZrO2]/[weight all crystalline phases])*100). The tetragonal ZrO2 phase may, in some embodiments, be dispersed throughout the residual glass phase. In other embodiments, the crystalline ZrO2 phase “decorates” or is near or in contact with the lithium disilicate phase. In some embodiments, the optimal crystal sizes for tetragonal ZrO2 is from about 0.1 to 2 μm, 2 to 5 μm, 0.1 to 10 μm, about 0.3 to 7 μm, about 0.5 to 4 μm, about 0.8 to 3 μm, or about 0.5 to 3 μm.


In some embodiments, the tetragonal ZrO2 phase may comprise 1 to 20 wt % of the total glass crystalline phase of the composition.


The glass ceramic further comprises a lithium disilicate phase. In some embodiments, the lithium disilicate phase comprises about 5 to about 60 vol % of the total crystalline phase glass ceramic composition. In some embodiments, the lithium disilicate phase may comprise 20 to 60 vol % of the total crystalline phase of the glass ceramic. In some embodiments, the lithium disilicate phase makes up about 70 vol % of the total crystalline phase of the glass ceramic composition. The lithium disilicate crystals may have a lath-like structure, with and aspect ratio of from about 1.5:1 to 12:1, 2:1 to 8:1 or greater than 2:1, with the longer dimension being, for example, less than 2 μm, or at least 2 μm, 5 μm, 8 μm, or 10 μm.


In an embodiment, the lithium disilicate phase is the predominant crystalline phase in the glass ceramic. By “predominant crystalline phase” it is meant the crystalline phase has the greatest vol % of any crystalline phase present in the glass ceramic.


In an embodiment, the tetragonal ZrO2 phase is the minor crystalline phase in the glass ceramic. By “minor crystalline phase” it is meant the crystalline phase has 20 vol % or less of the total vol % crystalline phase present in the glass ceramic.


In some embodiments, the glass ceramic further comprises one or more additional crystal phases, such as a lithium phosphate, lithium alumosilicate, β-spodumene solid solution, n-quartz solid solution, or α-quartz and α-quartz-solid-solution phase or combinations thereof. In some embodiments, the additional crystal phases comprise, in total, about 0-25 wt % of the glass ceramic or 0-25 vol %. In some embodiments, there may be two distinct crystalline phases. In some embodiments, there may be two distinct crystalline phases and trace crystalline phase, and the two distinct crystalline are lithium disilicate and tetragonal ZrO2, and one trace crystalline phase that is 1 vol % of the total crystalline phase.


In some embodiments, there may be a trace amount of one additional crystal phase, and trace crystalline phase is equal to or less than 1 vol % of the total crystalline phase.


It may be desirable that the glass ceramic comprises a certain number of distinct phases. In some embodiments, the glass ceramic comprises 4 or 3 distinct phases, where the glass ceramic comprises a lithium disilicate phase and a tetragonal ZrO2 phase.


The glass phase, in some embodiments, may make up 5-50 vol % of the total glass ceramic composition.


In some embodiments, the tetragonal ZrO2/lithium disilicate glass ceramic and/or the precursor glass used to form the glass ceramic may comprise additional components. In some embodiments, the glass ceramic and/or the precursor glass used to form the glass ceramic comprises 18 to 40 mol % Li2O, 19 to 37 mol % Li2O, 25 to 35 mol % Li2O, or 30 to 35 mol % Li2O. In some embodiments, the glass ceramic and/or the precursor glass used to form the glass ceramic comprises about: 0 to 7 mol % Al2O3, 0 to 5 mol % Al2O3, 0 to 4 mol % Al2O3, 0 to 3 mol % Al2O3, about 0.1 to 7 mol % Al2O3, about 0.1 to 5 mol % Al2O3, about 0.1 to 4 mol % Al2O3, about 0.1 to 3 mol % Al2O3, 0.5 to 7 mol % Al2O3, 0.5 to 5 mol % Al2O3, 0.5 to 4 mol % Al2O3, or 0.5 to 3 mol % Al2O3.


In some embodiments, the glass ceramic may further comprise at least one of crystalline cubic ZrO2 or monoclinic ZrO2 phases. In some embodiments, the glass ceramic may comprise a monoclinic ZrO2 phase. In such instances, the ratio of weight fraction (or weight percentage) of tetragonal zirconia to that of monoclinic zirconia is at least about 8:1 (i.e., tetragonal-ZrO2 (wt %)/monclinic-ZrO2 (wt %))≥8); in some embodiments, at least about 10:1 (tetragonal-ZrO2 (wt %)/monclinic-ZrO2 (wt %))≥10); in other embodiments, at least about 15 (tetragonal-ZrO2 (wt %)/monclinic-ZrO2 (wt %))≥15); and in still other embodiments, at least about 20 (tetragonal-ZrO2 (wt %)/monclinic-ZrO2 (wt %))≥20). In some embodiments the amount of monclinic-ZrO2 in the glass ceramic is from 0 to 3 wt %, 0 to 1 wt %, >0 to 3 wt %, or >0 to 1 wt %. The weight fraction ratio of the tetragonal to monoclinic zirconia phases may be determined by x-ray diffraction methods, such as Rietveld refinement, which are known in the art.


In some embodiments, the glass ceramic and/or the precursor glass used to form the glass ceramic comprises a combination of SiO2, Li2O, ZrO2, and optionally, Al2O3, alkali oxides, alkaline earth oxides, and rare earth oxides. For example, the glass ceramic and/or precursor glass in embodiments may comprise from about 50 mol % to 75 mol % SiO2 (50 mol %≤SiO2≤75 mol %); from 18 mol % to 40 mol % Li2O (18 mol %≤Li2O≤40 mol %); from 3 mol % to 15 mol % ZrO2 (3 mol %≤ZrO2≤15 mol %); from 0 mol % to 5 mol % Al2O3 (0 mol %≤Al2O3≤5 mol %); from 0 mol % to 5 mol % Na2O (0 mol %≤Na2O≤5 mol %); from 0 mol % to 5 mol % of at least one alkaline earth oxide (RO; R=Mg, Sr, Ca, Ba) (0 mol %≤RO≤5 mol %); from 0 mol % to 5 mol % of at least one transition metal oxide (TMO) (e.g., Zn, Ti, Fe, etc.) (0 mol %≤TMO≤5 mol %); and from 0 mol % to 5 mol % of at least one rare earth oxide (REO; i.e., oxides of scandium, yttrium, and the lanthanides) (0 mol %≤REO≤5 mol %).


SiO2, along with Al2O3, B2O3, P2O5, ZrO2 and SnO2, are network formers when present in the glass ceramic and/or the precursor glass. SiO2, which is the largest oxide component of the glass ceramic and/or the precursor glass in terms of weight percent, may be included to provide high temperature stability and chemical durability. In some embodiments, the glass ceramic and/or the precursor glass can comprise from 50 to 75 mol % SiO2. In some embodiments, the glass ceramic and/or the precursor glass can comprise from 55 to 70 mol % SiO2. In some embodiments, the glass ceramic and/or the precursor glass can comprise from 57 to 65 mol % SiO2. In some embodiments, the glass ceramic and/or the precursor glass can comprise from 57 to 70 mol % SiO2. In some embodiments, the glass ceramic and/or the precursor glass can comprise about 50 to 75 mol %, 50 to 70 mol %, 50 to 65 mol %, 50 to 60 mol %, 55 to 75 mol %, 57 to 70 mol %, 57 to 65 mol %, 55 to 70 mol %, or 55 to 65 mol % SiO2. In some embodiments, the glass ceramic and/or the precursor glass comprises 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, or 75 mol % SiO2.


Li2O may provide the basis for the lithium disilicate phase. In some embodiments, the glass ceramic and/or the precursor glass can comprise from 18 to 40 mol % Li2O. In other embodiments, the glass ceramic and/or the precursor glass can comprise 25 to 36 mol % Li2O. In other embodiments, the glass ceramic and/or the precursor glass can comprise 18 to 30 mol % Li2O. In other embodiments, the glass ceramic and/or the precursor glass can comprise 30 to 35 mol % Li2O. In some embodiments, the glass ceramic and/or the precursor glass can comprise from 18 to 40 mol %, 18 to 36 mol %, 18 to 30 mol %, 18 to 25 mol %, 20 to 40 mol %, 20 to 36 mol %, 20 to 30 mol %, 20 to 25 mol %, 25 to 40 mol %, 25 to 36 mol %, 25 to 30 mol %, 30 to 40 mol %, 30 to 36 mol %, or 36 to 40 mol %. In some embodiments, the glass ceramic and/or the precursor glass can comprise 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, or 40 mol % Li2O.


It may be desirable that the glass ceramic comprise a certain silicon to lithium ratio (e.g., SiO2 to Li2O ratio). In some embodiments, the silicon to lithium ratio is from 1.8 to 2.7. In some embodiments, the glass ceramic material has a silicon to lithium ratio is from about 1.8 to 2.7 and 4 to 9.5 mol % ZrO2.


Zirconium dioxide or zirconia is the primary component of the tetragonal and other crystalline ZrO2 phases. In some embodiments, the glass ceramic and/or the precursor glass can comprise from 3 to 25 mol % ZrO2. In some embodiments, the glass ceramic and/or the precursor glass can comprise from 4 to 20 mol % ZrO2. In some embodiments, the glass ceramic and/or the precursor glass can comprise from about 5.5 to about 8.5 mol % ZrO2. In some embodiments, the glass ceramic and/or the precursor glass can comprise greater than or equal to 6 mol % ZrO2. In some embodiments, the glass ceramic and/or the precursor glass can comprise from 6 to 15 mol % ZrO2. In some embodiments, the glass ceramic and/or the precursor glass can comprise from about: 3 to 25 mol %, 3 to 20 mol %, 3 to 18 mol %, 3 to 15 mol %, 3 to 12 mol %, 3 to 10 mol %, 3 to 8 mol %, 4 to 25 mol %, 4 to 20 mol %, 4 to 18 mol %, 4 to 15 mol %, 4 to 12 mol %, 4 to 10 mol %, 4 to 8 mol %, 6 to 25 mol %, 6 to 20 mol %, 6 to 18 mol %, 6 to 15 mol %, 6 to 12 mol %, 6 to 10 mol %, ZrO2. In some embodiments, the glass ceramic and/or the precursor glass can comprise 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, or 25 mol % ZrO2.


Al2O3 may provide, among other benefits, for a) maintaining the lowest possible liquidus temperature, b) lowering the expansion coefficient, or c) enhancing the strain point. In some embodiments, the glass ceramic and/or the precursor glass can comprise from 0 to 5 mol % Al2O3. In some embodiments, the glass ceramic and/or the precursor glass can comprise from 0.1 to 5 mol % Al2O3. In some embodiments, the glass ceramic and/or the precursor glass can comprise less than 2 mol % Al2O3. In some embodiments, the glass ceramic and/or the precursor glass can comprise from about 0 to 3 mol % Al2O3 or >0 to 3 mol % Al2O3. In some embodiments, the glass ceramic and/or the precursor glass can comprise from 1 to 4 mol % Al2O3. In some embodiments, the glass ceramic and/or the precursor glass can comprise from about: 0 to 5 mol %, 0 to 4 mol %, 0 to 3 mol %, 0 to 2 mol %, 0.1 to 5 mol %, 0.1 to 4 mol %, 0.1 to 3 mol %, 0.1 to 2 mol %, 1 to 5 mol %, 1 to 4 mol %, or 1 to 3 mol % Al2O3. In some embodiments, the glass ceramic and/or the precursor glass can comprise about 0, 0.1, 1, 2, 3, 4, or 5 mol % Al2O3.


Without being bound by theory, it is believed that limiting the content of B2O3 in the glasses and glass ceramics described herein to from 0 to 5 wt % provides a durable glass ceramic. In some embodiments, the glass ceramic and/or the precursor glass can comprise from 0 to 5 mol % B2O3. In some embodiments, the glass ceramic and/or the precursor glass can comprise from >0 to 5 mol % B2O3. In some embodiments, the glass ceramic and/or the precursor glass can comprise from about 0 to 3 mol % B2O3 or >0 to 3 mol % B2O3. In some embodiments, the glass ceramic and/or the precursor glass can comprise from 1 to 4 mol % B2O3. In some embodiments, the glass ceramic and/or the precursor glass can comprise from about: 0 to 5 mol %, 0 to 4 mol %, 0 to 3 mol %, 0 to 2 mol %, 0.001 to 5 mol %, 0.001 to 4 mol %, 0.001 to 3 mol %, 0.001 to 2 mol %, 1 to 5 mol %, 1 to 4 mol %, or 1 to 3 mol % B2O3. In some embodiments, the glass ceramic and/or the precursor glass can comprise about 0, 0.1, 1, 2, 3, 4, or 5 mol % B2O3.


Phosphorous pentoxide, P2O5, may be present in order to stabilize the tetragonal ZrO2. In some embodiments, the glass ceramic and/or the precursor glass can comprise from >0 to 5 mol % P2O5. In some embodiments, the glass ceramic and/or the precursor glass can comprise from 0.2 to 5 mol % P2O5. In some embodiments, the glass ceramic and/or the precursor glass can comprise from about >0 to 3 mol % P2O5 or 0.2 to 3 mol % P2O5. In some embodiments, the glass ceramic and/or the precursor glass can comprise from 1 to 4 mol % P2O5. In some embodiments, the glass ceramic and/or the precursor glass can comprise from about: 0.2 to 5 mol %, 0.2 to 4 mol %, 0.2 to 3 mol %, 0.2 to 2 mol %, 0.001 to 5 mol %, 0.001 to 4 mol %, 0.001 to 3 mol %, 0.001 to 2 mol %, 1 to 5 mol %, 1 to 4 mol %, or 1 to 3 mol % P2O5. In some embodiments, the glass ceramic and/or the precursor glass can comprise about 0, 0.001, 1, 2, 3, 4, or 5 mol % P2O5.


Rare earth oxides may be present in order to stabilize the tetragonal ZrO2. In some embodiments, the glass ceramic and/or the precursor glass comprises from 0 mol % to 5 mol % of at least one rare earth oxide (REO; i.e., oxides of scandium, yttrium, and the lanthanides) (0 mol %≤REO≤5 mol %). In some embodiments, the glass ceramic and/or the precursor glass comprises from greater than 0 mol % to 5 mol % of at least one rare earth oxide (REO; i.e., oxides of scandium, yttrium, and the lanthanides) (0 mol %<REO≤5 mol %), where ‘greater than 0’ means any positive value, such as 0.001 mol %. The glass ceramic and/or the precursor glass may, in some embodiments, comprise from 0 mol % to 3 mol % or from greater than 0 mol % to 2 mol % Y2O3 (0 mol %≤Y2O3≤3 mol % or 0 mol %≤Y2O3≤2 mol %). In some embodiments, the ratio of Y2O3 (mol %)/ZrO2 (mol %) is less than 0.2, 0.15, 0.1, 0.05, or 0.1. In some embodiments, the glass ceramic and/or the precursor glass comprises from about: 0 to 5 mol %, 0.1 to 5 mol %, 1 to 5 mol %, 2 to 5 mol %, 0 to 4 mol %, 0 to 3 mol %, 0 to 2 mol %, 0 to 1 mol %, 0.1 to 4 mol %, 0.1 to 3 mol %, 0.1 to 2 mol %, or 0.1 to 1 mol %, 0 to about 0.5 mol %, 0 to about 0.1 mol %, 0 to about 0.05 mol %, or 0 to about 0.01 mol % CeO2.


Alkali oxides may be present in the glass ceramic and/or the precursor glass. In some embodiments, the glass ceramic and/or the precursor glass comprises from 0 mol % to about 14 mol % R2O (0 mol %<R2O≤14 mol %), where R is the sum of the alkali metals Na, K, and Cs (not Li), in the glass ceramic and/or the precursor glass. In some embodiments, the glass ceramic and/or the precursor glass can comprise from 0 to 10 or 0 to 8 mol % R2O. In some embodiments, the glass ceramic and/or the precursor glass can comprise from 0 to 14, 0 to 10, or 0 to 8 mol % R2O. In some embodiments, the glass ceramic and/or the precursor glass can comprise from 1 to 4 mol % R2O. In some embodiments, the glass ceramic and/or the precursor glass can comprise from about: 0 to 14 mol %, 0 to 10 mol %, 0 to 8 mol %, 0 to 6 mol %, 0 to 4 mol %, 0.1 to 14 mol %, 0.1 to 10 mol %, 0.1 to 8 mol %, 0.1 to 6 mol %, 0.1 to 4 mol %, 1 to 14 mol %, 1 to 10 mol %, 1 to 8 mol %, 1 to 6 mol %, 2 to 14 mol %, 2 to 10 mol %, 2 to 8 mol %, 2 to 6 mol %, 4 to 14 mol %, 4 to 10 mol %, 4 to 8 mol %, 6 to 14 mol %, 6 to 10 mol %, 8 to 14 mol % or 8 to 10 mol % R2O. In some embodiments, the glass ceramic and/or the precursor glass can comprise about 0, 0.1, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, or 14 mol % R2O.


Na2O can be useful in the glass ceramic and/or the precursor glass for ion exchange and chemical tempering. In some embodiments, the greater glass ceramic and/or the precursor glass comprises from 0 mol % to about 5 mol % Na2O (0 mol %≤Na2O≤5 mol %). In some embodiments, the glass ceramic and/or the precursor glass can comprise from greater than 0 to 5 mol % Na2O. In some embodiments, the glass ceramic and/or the precursor glass can comprise from about 0 to 3 mol % Na2O or >0 to 3 mol % Na2O. In some embodiments, the glass ceramic and/or the precursor glass can comprise from 0.5 to 4 mol % Na2O. In some embodiments, the glass ceramic and/or the precursor glass can comprise from about: 0 to 5 mol %, 0 to 4 mol %, 0 to 3 mol %, 0 to 2 mol %, 0 to 5 mol %, 0.1 to 4 mol %, 0.1 to 3 mol %, 0.1 to 2 mol %, 1 to 5 mol %, 1 to 4 mol %, or 1 to 3 mol % Na2O. In some embodiments, the glass ceramic and/or the precursor glass can comprise about 0, 0.1, 1, 2, 3, 4, or 5 mol % Na2O.


K2O may also be useful in ion exchange and may be present in the glass ceramic and/or the precursor glass at amounts from 0 mol % to about 10 mol % K2O (0 mol %≤K2O≤10 mol %). In some embodiments, the glass ceramic and/or the precursor glass can comprise from >0 to 10 mol % K2O. In some embodiments, the glass ceramic and/or the precursor glass can comprise from about 0 to 5 mol % K2O or >0 to 3 mol % K2O. In some embodiments, the glass ceramic and/or the precursor glass can comprise from 0.5 to 4 mol % K2O. In some embodiments, the glass ceramic and/or the precursor glass can comprise from 0 to 10 mol %, 0 to 8 mol %, 0 to 5 mol %, 0 to 4 mol %, 0 to 3 mol %, 0.1 to 10 mol %, 0.1 to 8 mol %, 0.1 to 5 mol %, 0.1 to 3 mol %, 1 to 10 mol %, 1 to 8 mol %, 1 to 5, 1 to 4 mol %, 1 to 3 mol %, 2 to 10 mol %, 2 to 8 mol %, or 2 to 4 K2O. In some embodiments, the glass ceramic and/or the precursor glass can comprise about 0, 0.1, 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 mol % K2O.


Alkaline earth oxides may provide advantages for ion exchange in the glass ceramic or precursor glass, along with improving other properties in the materials. In some embodiments, the glass ceramic and/or the precursor glass comprises from 0 mol % to about 10 mol % MO (0 mol %≤MO≤10 mol %), where M is the sum of the alkaline earth metals Mg, Ca, Sr, and Ba, in the glass ceramic and/or the precursor glass. In some embodiments, the glass ceramic and/or the precursor glass can comprise from 0 to 8 mol % MO. In some embodiments, the glass ceramic and/or the precursor glass can comprise from 0 to 5 mol % MO. In some embodiments, the glass ceramic and/or the precursor glass can comprise from 1 to 8 mol % MO. In some embodiments, the glass ceramic and/or the precursor glass can comprise from 0 to 10 mol %, 0 to 8 mol %, 0 to 6 mol %, 0 to 4 mol %, 1 to 10 mol %, 1 to 8 mol %, 1 to 6 mol % 2 to 10 mol %, 2 to 8 mol %, or 2 to 6 mol % MO. In some embodiments, the glass ceramic and/or the precursor glass can comprise about 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 mol % MO.


Titanium dioxide, TiO2, can provide fracture toughness to the glass ceramic and/or the precursor glass, either alone or in combination with the tetragonal ZrO2. In some embodiments, the glass ceramic and/or the precursor glass may further comprise from 0 mol % to about 10 mol % TiO2, >0 mol % to about 10 mol % TiO2, 0 mol % to about 5 mol % TiO2, or >0 mol % to about 5 mol % TiO2. In some embodiments, the glass ceramic and/or the precursor glass may comprise about 0 to 5 mol %, 0 to 4 mol %, 0 to 3 mol %, 0 to 2 mol %, 0 to 1 mol %, 0.1 to 10 mol %, 0.1 to 5 mol %, 0.1 to 4 mol %, 0.1 to 3 mol %, 0.1 to 2 mol %, 0.1 to 1 mol %, 0.01 to 3 mol %, or 0.1 to 2 mol % TiO2.


Additional components can be incorporated into the glass ceramic and/or the precursor glass to provide additional benefits or may be incorporated as contaminants typically found in commercially-prepared glass. For example, additional components can be added as fining agents (e.g., to facilitate removal of gaseous inclusions from melted batch materials used to produce the glass) and/or for other purposes. In some embodiments, the glass ceramic and/or the precursor glass may comprise one or more compounds useful as ultraviolet radiation absorbers. In some embodiments, the glass ceramic and/or the precursor glass can comprise 3 mol % or less MnO, Nb2O5, MoO3, Ta2O5, WO3, SnO2, Fe2O3, As2O3, Sb2O3, F, Cl, Br, or combinations thereof. In some embodiments, the glass ceramic and/or the precursor glass can comprise from 0 to about 3 mol %, 0 to about 2 mol %, 0 to about 1 mol %, 0 to 0.5 mol %, 0 to 0.1 mol %, 0 to 0.05 mol %, or 0 to 0.01 mol % MnO, ZnO, Nb2O5, MoO3, Ta2O5, WO3, SnO2, Fe2O3, As2O3, Sb2O3, F, Cl, Br, or combinations thereof. In some embodiments, the glass ceramic and/or the precursor glass can comprise from 0 to about 3 mol %, 0 to about 2 mol %, 0 to about 1 mol %, 0 to about 0.5 mol %, 0 to about 0.1 mol %, 0 to about 0.05 mol %, or 0 to about 0.01 mol % SnO2 or Fe2O3, or combinations thereof. The glasses, according to some embodiments, can also include various contaminants associated with batch materials and/or introduced into the glass by the melting, fining, and/or forming equipment used to produce the glass.


In some embodiments, the glass ceramic comprises cesium, rubidium, tungsten, or tantalum. In some embodiments, the glass ceramic comprises a combination of two or more of cesium, rubidium, tungsten, tantalum, niobium, yttrium, lanthanum, gadolinium and ytterbium.


In some embodiments, the glass ceramic described herein may also contain other secondary crystalline phases. Such phases may be beneficial for toughening (as in the case of lithium disilicate) or for chemical strengthening by ion exchange processes known in the art (as is the case for β-spodumene solid solutions or glass). In some cases, the crystalline phases are interlocked or the crystals are very close together, leaving an intermixed glass phase. These unique microstructures and phase assemblages are not available using traditional ceramic processing routes—the disclosed method provides these microstructures by homogenous nucleation of the precursor glass that results in the disclosed phase assemblages and microstructures without the use of high temperature sintering or the hazard of inhomogeneous dispersion of a ZrO2 phase in molten glass. Additionally, certain phases may also serve to decrease the coefficient of thermal expansion (CTE) of the glass ceramic material. Accordingly, the glass ceramic may further comprise at least one of a crystalline lithium alumosilicate phase, a cristobalite phase, a beta-spodumene phase, a lithiophosphate (Li3PO4) crystalline phase, a crystalline lithium orthophosphate phase, a quartz solid solution phase, a baddeleyite phase, a lithium metasilicate (Li2SiO3) phase, a monoclinic zirconia phase, a cubic zirconia phase, or a crystalline (Na,Li)ZrSi6O18 phase. As used herein the term “quartz solid solution” includes solid solutions of SiO2 and up to about 50 wt % Li(AlO2).


Non-limiting examples of precursor glasses and glass ceramic compositions, heat treatment (ceramming) schedules, and phase assemblages resulting from different ceramming/heat treatment schedules are listed in Table 1, 2 and 3. Table 1 also includes comments regarding the general appearance of the formed glass ceramic.









TABLE 1





Examples of precursor compositions (expressed in mol %), ceramming schedules,


and phase assemblages resulting from different heat treatment schedules.



















Sample
1
2
3
4





SiO2
69
69
69
69


Al2O3
0
0
0
0


Li2O
28
28
28
28


Na2O
1.5
1.5
1.5
1.5


MgO
0
0
0
0


CaO
0
0
0
0


ZrO2
3
8
13
18


P2O5
1.5
1.5
1.5
1.5


Y2O3






SnO2






Ceramming cycle
2 hr at 700° C.,
2 hr at 700° C.,
2 hr at 700° C.,
2 hr at 700° C.,



4 hr at 850° C.
4 hr at 850° C.
4 hr at 850° C.
4 hr at 850° C.


Phase assemblage
lithium disilicate,
lithium disilicate,
t-ZrO2,
Glass



cristobalite,
quartz, cristobalite,
lithium disilicate,




lithiophosphate
lithiophosphate
cristobalite,






baddeleyite,






lithiophosphate



Appearance
Translucent white
Translucent white
Opaque white
Transparent


Fracture toughness

1.75
2.53



(MPa · m1/2)














Sample
5
6
7
8





SiO2
59
59
59
59


Al2O3
0
0
0
0


Li2O
35
35
35
35


Na2O
1.5
1.5
1.5
1.5


MgO
0
0
0
0


CaO
0
0
0
0


ZrO2
6
12
6
8


P2O5
1.5
1.5
1.5
1.5


Y2O3






SnO2






Ceramming cycle
2 hr at 700° C.,
2 hr at 700° C.,
2 hr at 750° C.,
2 hr at 700° C.,



4 hr at 850°
4 hr at 850° C.
4 hr at 850° C.
4 hr at 850° C.


Phase assemblage
t-ZrO2,
t-ZrO2,
t-ZrO2,
t-ZrO2,



lithium disilicate,
lithium
lithium disilicate,
lithium disilicate,



lithium
metasilicate,
lithium metasilicate,
lithium metasilicate,



metasilicate,
cristobalite,
baddeleyite,
baddeleyite,



baddeleyite,
baddeleyite,
lithiophosphate
lithiophosphate



lithiophosphate
lithiophosphate




Appearance
Opaque white
Opaque white
Opaque white
Opaque white


Fracture toughness
2.73
2.36
3.00
3.35


(MPa · m1/2)






Flexural strength


556
332


(MPa)






Ceramming cycles


2 hr at 750° C.,
2 hr at 750° C.,





4 hr at 900° C.
4 hr at 900° C.


Fracture toughness


3.90
5.30


(MPa · m1/2)














Sample
9
10
11
12





SiO2
59
59
64
64


Al2O3
0
0
0
0


Li2O
35
35
31
31


Na2O
1.5
1.5
1.5
1.5


MgO
0
0
0
0


CaO
0
0
0
0


ZrO2
10
12
5
10


P2O5
1.5
1.5
1.5
1.5


Y2O3






SnO2






Ceramming cycle
2 hr at 700° C.,
2 hr at 700° C.,
2 hr at 700° C.,
2 hr at 700° C.,



4 hr at 850° C.
4 hr at 850° C.
4 hr at 850° C.
4 hr at 850° C.


Phase assemblage
t-ZrO2,
t-ZrO2,
t-ZrO2,
t-ZrO2,



lithium disilicate,
lithium disilicate,
lithium disilicate,
lithium disilicate,



lithium
lithium
Baddeleyite,
lithium metasilicate,



metasilicate,
metasilicate,
lithiophosphate
baddeleyite,



baddeleyite,
baddeleyite,

cristobalite,



lithiophosphate
lithiophosphate

lithiophosphate


Appearance
Opaque white
Opaque white
Opaque white
Opaque white


Fracture toughness
3.77

2.28
3.15


(MPa · m1/2)






Flexural strength
191





(MPa)






Ceramming cycles
2 hr at 750° C.,
2 hr at 750° C.,





6 hr at 900° C.
4 hr at 900° C.




Fracture toughness
7.93
6.10




(MPa · m1/2)














Sample
13
14
15
16





SiO2
64.2
64.2
64.2
64.2


Al2O3
3.9
1.9
0.5
0.5


Li2O
19.6
19.6
19.6
19.6


Na2O
1.3
1.3
1.3
1.3


MgO






CaO






ZrO2
10
12
13.4
13.4


P2O5
2.8
2.8
2.8
2.8


Y2O3
0
0
0
0.5


SnO2
0.1
0.1
0.1
0.1


Ceramming cycle
2 hr at 700° C.,
2 hr at 700° C.,
2 hr at 700° C.,
2 hr at 700° C.,



4 hr at 850° C.
4 hr at 850° C.
4 hr at 850° C.
4 hr at 850° C.


Phase assemblage
t-ZrO2,
t-ZrO2,
t-ZrO2,
t-Y/ZrO2*,



m-ZrO2,
m-ZrO2,
m-ZrO2,
SiO2, ZrSiO4,



quartz s.s.,
SiO2,
SiO2,
lithiophosphate,



SiO2,
lithiophosphate
lithiophosphate,
lithium metasilicate,



lithiophosphate

lithium metasilicate,
NaLiZrSi6O18





NaLiZrSi6O18



Appearance
white opaque,
white, opaque,
layered, broken up on
layered, broken up



medium grained
fine grained
ceramming
on ceramming














Sample
17
18
19
20





SiO2
64.2
62.2
60.2
60.2


Al2O3
0.5
3.9
3.9
0.5


Li2O
19.6
19.6
19.6
19.6


Na2O
1.3
1.3
1.3
1.3


MgO






CaO






ZrO2
13.4
10
10
13.4


P2O5
2.8
2.8
2.8
2.8


Y2O3
1.5
0
0
0


SnO2
0.1
0.05
0.05
0.05


Ceramming cycle
2 hr at 700° C.,
2 hr at 700° C.,
2 hr at 700° C.,
2 hr at 700° C.,



4 hr at 850° C.
4 hr at 850° C.
4 hr at 850° C.
4 hr at 850° C.


Phase assemblage
t-ZrO2, ZrSiO4,
t-ZrO2,
t-ZrO2,
t-ZrO2,



SiO2,
m-ZrO2,
m-ZrO2,
m-ZrO2,



lithiophosphate,
b-spodumene, SiO2,
b-spodumene, SiO2,
SiO2,



lithium metasilicate,
lithiophosphate,
lithiophosphate,
lithiophosphate,



NaLiZrSi6O18
lithium metasilicate
lithium metasilicate
lithium metasilicate


Appearance
white, opaque, fine
white opaque, fine
white opaque, fine
broke up on



grained
to medium grain
to medium grain
ceramming, flaky














Sample
21
22






SiO2
62.2
62.2



Al2O3
4.9
1.5



Li2O
19.6
19.6



Na2O
1.3
1.3



MgO





CaO





ZrO2
10
13.4



P2O5
2.8
2.8



Y2O3
0
0



SnO2
0.05
0.05



Ceramming cycle
2 hr at 700° C.,
2 hr at 700° C.,




4 hr at 850° C.
4 hr at 850° C.



Phase assemblage
t-ZrO2,
t-ZrO2,




m-ZrO2,
m-ZrO2,




b-spodumene,
SiO2, lithiophosphate,




lithiophosphate, lithium
lithium metasilicate




metasilicate




Appearance
white opaque, fine to
white opaque, fine to




medium grain
medium grain





Note:


in Table 1 tetragonal ZrO2 is denoted by “t-ZrO2,” monoclinic ZrO2 is denoted by “m-ZrO2,” and quartz solid solution is denoted by “quartz s.s.”

















TABLE 2







Example No.
Ideal range
1
2
3





Oxide mol %






SiO7
55-65
61.5
64.4
60.3


Li7O
22-32
25.6
24.3
28.8


CoO
 0-10





MgO
 0-10





SrO
0-5





ZnO
0-5





Na2O
0-5

1.4
1.4


K2O
0-5
2.1




Cs2O
0-2





Rb2O
0-2





Al2O3
0-5
1.7




B2O3
0-5





Y2O3
0-3





La2O3
0-3





In2O3
0-1





Ga2O3
0-1





Bi2O3
0-1





ZrO2
 5-10
7.8
8.3
8.0


TiO2
0-2





CeO2
0-1





SnO2
0-2





MnO2
0-2





P2O5
0-5
1.3
1.6
1.5


Nb2O5
0-1





Ta7O5
0-1





V7O5

0-0.5






MoO3
0-2





WO3
0-2





GeO7
0-5





F-
0-1





Σ
  100
100.0
100.0
100.0


SiO2/Li2O
1.8-3
2.40
2.65
2.09


Tg/° C.
450-600
537
543
525


Tmelt/° C.
1200-1600
1500
1450
1500


tmelt/min.
 5-120
120
120
120


Tnucleation/° C.
450-600
560
560
550


tnucleation/min
 5-120
30
30
60


TC1/° C.
800-900
820
840
880


tC1/min
 5-120
1440
60
60


heating rate K/min
 5-140
30
30
30


RI-XRD






main cryst. phase
Li2Si2O5
Li2Si2O5
Li2Si2O5
Li2Si2O5


other cryst. phase
t-ZrO2, Li3PO4
m-ZrO2, t-ZrO2, Li2SiO3,
t-ZrO2, Li3PO4
t-ZrO2, Li3PO4




Li3PO4, Cristebalite




t-ZrO2 crystal size
≤2 μm





TSinter/° C.






tSinter/min.






main cryst. phase






other cryst. phase






Tpress/° C.






tpress/° C.






heating rate K/min






main cryst. phase






other cryst. phase






σB/Mpa
 >300





L*
60-95





a*
−1-12





b*
 1-35





CR
65-85


92


Klc (SEVNB)
>2
2.4

2.3


Klc (Vickers)
>2





Klc (Chevron notch)
≥3





CTE/1*10−6K−1(25° C.-500° C.)
 8-13





chem. Solubility (acetic
 0-99


11


acid)/μg*cm−2














Example No.
Ideal range
4
5
6





Oxide mol %






SiO2
55-65
63.8
58.5
59.0


Li2O
22-32
27.0
29.6
28.0


CaO
 0-10





MgO
 0-10


3.5


SrO
0-5





ZnO
0-5





Na2O
0-5
1.4
1.4



K2O
0-5





Cs7O
0-2





Rb2O
0-2





Al2O3
0-5





B7O3
0-5





Y2O3
0-3





La2O3
0-3





In2O3
0-1





Ga2O3
0-1





Bi2O3
0-1





ZrO2
 5-10
6.2
9.0
8.0


TiO2
0-2





CeO7
0-1





SnO2
0-2





MnO2
0-2





P2O3
0-5
1.6
1.5
1.5


Nb2O5
0-1





Ta2O5
0-1





V2O5

0-0.5






MoO3
0-2





WO3
0-2





GeO2
0-5





F-
0-1





Σ
  100
100.0
100.0
100.0


SiO2/Li2O
1.8-3
2.36
1.98
2.11


Tg/° C.
450-600
509
530
534


Tmelt/° C.
1200-1600
1450
1450
1450


tmelt/min.
 5-120
120
120
120


Tnucleation/° C.
450-600
530
550
550


tnucleation/min
 5-120
30
30
30


TC1/° C.
800-900
840
880
840


tC1/min
 5-120
60
60
60


heating rate K/min
 5-140
30
30
30


RT-XRD






main cryst. phase
Li2Si2O5
Li2Si2O5 (42.4 wt %)
Li2Si2O5
Li2Si2O5 (50 wt %)


other cryst. phase
t-ZrO2, Li3PO4
m-ZrO2 (1.6 wt %), t-
Zektzerite, m-ZrO2, t-
m-ZrO2 (10.2 wt %), t-




ZrO2(1.4 wt %), Li3PO4
ZrO2, Li2SiO3, Li3PO4,
ZrO2(5.7 wt %), Li3PO4




(6.4 wt %), Cristobalite
Cristobalite
(7.5 wt %), Cristobalite




(0.7 wt %)

(7.6 wt %), Quartz(0.3 wt %)


t-ZrO2 crystal size
≤2 μm





TSinter/° C.






tSinter/min.






main cryst. phase






other cryst. phase






Tpress/° C.






tpress/° C.






heating rate K/min






main cryst. phase






other cryst. phase






σB/Mpa
 >300





L*
60-95





a*
−1-12





b*
 1-35





CR
65-85





Klc (SEVNB)
>2
2.7




Klc (Vickers)
>2





Klc (Chevron notch)
≥3





CTE/1*10−6K−1(25° C.-500° C.)
 8-13


12.4


chem. Solubility (acetic
 0-99


30


acid)/μg*cm−2














Example No.
Ideal range
7
8
9





Oxide mol %






SiO7
55-65
58.6
60.0
60.0


Li2O
22-32
27.8
28.5
28.5


CaO
 0-10

1.5
1.5


MgO
 0-10
3.5




SrO
0-5





ZnO
0-5

0.5



Na2O
0-5





K2O
0-5





Cs2O
0-2





Rb2O
0-2





Al2O3
0-5
0.6




B7O3
0-5





Y2O3
0-3





La2O3
0-3





In2O3
0-1





Ga7O3
0-1





Bi2O3
0-1





ZrO2
 5-10
8.0
8.0
8.0


TiO2
0-2





CeO7
0-1


0.2


SnO2
0-2





MnO2
0-2





P7O5
0-5
1.5
1.5
1.5


Nb2O5
0-1





Ta2O5
0-1


0.3


V2O5

0-0.5






MoO3
0-2





WO3
0-2





GeO2
0-5





F-
0-1





Σ
  100
100.0
100.0
100.0


SiO2/Li2O
1.8-3
2.11
2.11
2.11


Tg/° C.
450-600
533
529
539


Tmelt/° C.
1200-1600
1450
1450
1450


tmelt/min.
 5-120
120
120
120


Tnucleation/° C.
450-600
550
550
560


tnucleation/min
 5-120
30
30
30


TC1/° C.
800-900
860
850
870


tC1/min
 5-120
60
60
60


heating rate K/min
 5-140
30
30
30


RT-XRD






main cryst. phase
Li2Si2O5
Li2Si2O5
Li2Si2O5
Li2Si2O5


other cryst. phase
t-ZrO2, Li3PO4
m-ZrO2, t-ZrO2, Li2SiO3,
m-ZrO2, t-ZrO2,
m-ZrO2, t-ZrO2, Li2SiO3,




Li3PO4, Cristobalite
Tridymite, Li3PO4,
Tridymite, Li3PO4,





Cristobalite
Cristobalite


t-ZrO2 crystal size
≤2 μm





TSinter/° C.






tSinter/min.






main cryst. phase






other cryst. phase






Tpress/° C.






tpress/° C.






heating rate K/min






main cryst. phase






other cryst. phase






σB/Mpa
 >300





L*
60-95





a*
−1-12





b*
 1-35





CR
65-85





Klc (SEVNB)
>2





Klc (Vickers)
>2





Klc (Chevron notch)
≥3





CTE/1*10−6K−1(25° C.-500° C.)
 8-13





chem. Solubility (acetic
 0-99





acid)/μg*cm−2














Example No.
Ideal range
10
11
12





Oxide mol %






SiO2
55-65
58.6
58.9
55.2


Li2O
22-32
27.8
27.9
29.6


CaO
 0-10





MgO
 0-10
3.2
1.0



SrO
0-5

2.0



ZnO
0-5





Na2O
0-5


1.4


K2O
0-5





Cs2O
0-2
0.3




Rb2O
0-2

0.1



Al2O3
0-5
0.6
0.6



B7O3
0-5





Y2O3
0-3





La2O3
0-3





In2O3
0-1





Ga2O3
0-1





Bl2O3
0-1





ZrO2
 5-10
8.0
8.0
7.9


TiO2
0-2





CeO7
0-1





SnO2
0-2





MnO2
0-2





P7O5
0-5
1.5
1.5
1.4


Nb2O5
0-1





Ta2O5
0-1





V2O5

0-0.5






MoO3
0-2





WO3
0-2





GeO2
0-5


4.5


F-
0-1





Σ
  100
100.0
100.0
100.0


SiO2/Li2O
1.8-3
2.11
2.11
1.86


Tg/° C.
450-600
525
529
510


Tmelt/° C.
1200-1600
1450
1450
1450


tmelt/min.
 5-120
120
120
120


Tnucleation/° C.
450-600
550
550
530


tnucleation/min
 5-120
30
30
30


TC1/° C.
800-900

820
850


tC1/min
 5-120

60
30


heating rate K/min
 5-140

30
30


RI-XRD






main cryst. phase
Li2Si2O5

Li2Si2O5
Li2SiO3


other cryst. phase
t-ZrO2, Li3PO4

Zektzerite, m-ZrO2, t-
t-ZrO2, Li3PO4





ZrO2, Li2SiO3, Li3PO4,






Cristobalite



t-ZrO2 crystal size
≤2 μm





TSinter/° C.






tSinter/min.






main cryst. phase






other cryst. phase






Tpress/° C.






tpress/° C.






heating rate K/min






main cryst. phase






other cryst. phase






σB/Mpa
 >300





L*
60-95





a*
−1-12





b*
 1-35





CR
65-85





Klc (SEVNB)
>2





Klc (Vickers)
>2





Klc (Chevron notch)
≥3





CTE/1*10−6K−1(25° C.-500° C.)
 8-13





chem. Solubility (acetic
 0-99





acid)/μg*cm−2














Example No.
Ideal range
13
14
15





Oxide mol %






SiO2
55-65
60.1
59.9
60.3


Li2O
22-32
28.8
28.8
28.8


CaO
 0-10





MgO
 0-10
1.0




SrO
0-5





ZnO
0-5





Na2O
0-5
0.6
1.0
1.4


K2O
0-5

0.4



Cs2O
0-2





Rb2O
0-2





Al2O3
0-5





B7O3
0-5





Y2O3
0-3





La2O3
0-3





In2O3
0-1





Ga7O3
0-1





Bi2O3
0-1





ZrO2
 5-10
7.0
8.0
8.0


TiO2
0-2
1.0




CeO7
0-1

0.3



SnO2
0-2





MnO2
0-2





P7O3
0-5
1.5
1.5
1.5


Nb2O5
0-1





Ta2O5
0-1





V2O5

0-0.5


0.1



MoO3
0-2





WO3
0-2





GeO2
0-5





F-
0-1





Σ
  100
100.0
100.0
100.0


SiO2/Li2O
1.8-3
2.09
2.08
2.09


Tg/° C.
450-600
522
526
525.3


Tmelt/° C.
1200-1600
1450
1450
1500


tmelt/min.
 5-120
120
120
120


Tnucleation/° C.
450-600
550
550
550


tnucleation/min
 5-120
30
10
60


TC1/° C.
800-900
820
870



tC1/min
 5-120
30
30



heating rate K/min
 5-140
30
30



RT-XRD






main cryst. phase
Li2Si2O5
Li2Si2O5
Li2Si2O5



other cryst. phase
t-ZrO2, Li3PO4
t-ZrO2, Li3PO4,
t-ZrO2, Tridymite,






Li3PO4,



t-ZrO2 crystal size
≤2 μm





TSinter/° C.



900


tSinter/min.



30


main cryst. phase



Li2Si2O5


other cryst. phase



m-ZrO2, t-ZrO2, Zektzerite,






Tridymite, Li3PO4,






Cristobalite


Tpress/° C.






tpress/° C.






heating rate K/min






main cryst. phase






other cryst. phase






σB/Mpa
 >300





L*
60-95
94.6




a*
−1-12
0.38




b*
 1-35
1.69




CR
65-85
95




Klc (SEVNB)
>2





Klc (Vickers)
>2





Klc (Chevron notch)
≥3





CTE/1*10−6K−1(25° C.-500° C.)
 8-13





chem. Solubility (acetic
 0-99





acid)/μg*cm−2














Example No.
Ideal range
16
17
18





Oxide mol %






SiO2
55-65
58.6
58.6
60.1


Li2O
22-32
27.8
27.8
28.8


CaO
 0-10





MgO
 0-10
3.5
3.5
1.0


SrO
0-5





ZnO
0-5





Na2O
0-5


0.6


K2O
0-5





Cs2O
0-2





Rb2O
0-2





Al2O3
0-5
0.6
0.6



B7O3
0-5





Y2O3
0-3





La2O3
0-3





In2O3
0-1





Ga2O3
0-1





Bl2O3
0-1





ZrO2
 5-10
8.0
8.0
7.0


TiO2
0-2


1.0


CeO7
0-1





SnO2
0-2





MnO2
0-2





P2O5
0-5
1.5
1.5
1.5


Nb2O5
0-1





Ta2O5
0-1





V2O5

0-0.5






MoO3
0-2





WO3
0-2





GeO2
0-5





F-
0-1





Σ
  100
100.0
100.0
100.0


SiO2/Li2O
1.8-3
2.11
2.11
2.09


Tg/° C.
450-600
532.8
532.8



Tmelt/° C.
1200-1600
1450
1450



tmelt/min.
 5-120
120
120



Tnucleation/° C.
450-600
550
550



tnucleation/min
 5-120
30
30



TC1/° C.
800-900

820



tC1/min
 5-120

60



heating rate K/min
 5-140

30



RT-XRD






main cryst. phase
Li2Si2O5

Li2SiO3, Li2Si2O5



other cryst. phase
t-ZrO2, Li3PO4

t-ZrO2, Li3PO4



t-ZrO2 crystal size
≤2 μm





TSinter/° C.






tSinter/min.






main cryst. phase






other cryst. phase






Tpress/° C.

870




tpress/° C.

25




heating rate K/min

60




main cryst. phase

Li2Si2O5




other cryst. phase

m-ZrO2, t-ZrO2,






Zektzerite, Tridymite,






Li3PO4, Cristobalite




σB/Mpa
 >300





L*
60-95
94.47




a*
−1-12
0




b*
 1-35
1.67




CR
65-85
84.38
62.5



Klc (SEVNB)
>2





Klc (Vickers)
>2





Klc (Chevron notch)
≥3





CTE/1*10−6K−1(25° C.-500° C.)
 8-13





chem. Solubility (acetic
 0-99





acid)/μg*cm−2














Example No.
Ideal range
19
20
21





Oxide mol %






SiO2
55-65
60.3
60.3
60.2


Li2O
22-32
28.8
28.6
28.6


CaO
 0-10





MgO
 0-10
1.5




SrO
0-5





ZnO
0-5





Na2O
0-5
1.4
1.4
1.4


K2O
0-5





Cs2O
0-2





Rb2O
0-2





Al2O3
0-5





B7O3
0-5





Y2O3
0-3


0.3


La2O3
0-3

0.2



In2O3
0-1





Ga2O3
0-1





Bi2O3
0-1





ZrO2
 5-10
8.0
8.0
8.0


TiO2
0-2





CeO7
0-1





SnO2
0-2





MnO2
0-2





P2O5
0-5

1.5
1.5


Nb2O5
0-1





Ta2O5
0-1





V2O5

0-0.5






MoO3
0-2





WO3
0-2





GeO2
0-5





F-
0-1

0.1



Σ
  100
100.0
100.0
100.0


SiO2/Li2O
1.8-3
2.09
2.11
2.10


Tg/° C.
450-600
519
527
531


Tmelt/° C.
1200-1600
1450

1500


tmelt/min.
 5-120
120

60


Tnucleation/° C.
450-600





tnucleation/min
 5-120





TC1/° C.
800-900


870


tC1/min
 5-120


60


heating rate K/min
 5-140


30


RT-XRD






main cryst. phase
Li2Si2O5


Li2Si2O5


other cryst. phase
t-ZrO2, Li3PO4


t-ZrO2, Li3PO4


t-ZrO2 crystal size
≤2 μm





TSinter/° C.

850




tSinter/min.

30




main cryst. phase

Li2Si2O5, t-ZrO2




other cryst. phase

Zektzerite, Li2SiO3, m-






ZrO2,




Tpress/° C.






tpress/° C.






heating rate K/min






main cryst. phase






other cryst. phase






σB/Mpa
 >300





L*
60-95





a*
−1-12





b*
 1-35





CR
65-85





Klc (SEVNB)
>2





Klc (Vickers)
>2





Klc (Chevron notch)
≥3





CTE/1*10−6K−1(25° C.-500° C.)
 8-13





chem. Solubility (acetic
 0-99





acid)/μg*cm−2














Example No.
Ideal range
22
23
24





Oxide mol %






SiO7
55-65
59.3
60.3
58.6


Li2O
22-32
28.3
28.8
27.8


CaO
 0-10





MgO
 0-10


3.2


SrO
0-5





ZnO
0-5





Na2O
0-5
1.4
1.4



K2O
0-5





Cs2O
0-2





Rb2O
0-2





Al2O3
0-5
1.5

0.6


B7O3
0-5





Y2O3
0-3





La2O3
0-3





In2O3
0-1





Ga2O3
0-1





Bi2O3
0-1





ZrO2
 5-10
8.0
8.0
8.0


TiO2
0-2





CeO2
0-1





SnO2
0-2





MnO2
0-2





P2O5
0-5
1.5
1.5
1.5


Nb2O5
0-1





Ta2O5
0-1





V2O5

0-0.5






MoO3
0-2





WO3
0-2


0.3


GeO2
0-5





F-
0-1





Σ
  100
100.0
100.0
100.0


SiO2/Li2O
1.8-3
2.10
2.09
2.11


Tg/° C.
450-600
527
543
529


Tmelt/° C.
1200-1600
1450
1450
1450


tmelt/min.
 5-120
120
120
120


Tnucleation/° C
450-600
550
540
560


tnucleation/min
 5-120
30
30
30


TC1/° C.
800-900
820
820
850


tC1/min
 5-120
300
2880
60


heating rate K/min
 5-140
20
20
30


RT-XRD






main cryst. phase
Li2Si2O5
Li2Si2O5
Li2Si2O5
Li2Si2O5


other cryst. phase
t-ZrO2, Li3PO4
Li2SiO3, t-ZrO2, m-ZrO2,
t-ZrO2, m-ZrO2, Li3PO4,
Zektzerite, m-ZrO2, t-




Cristobalite, Li3PO4
Cristobalite
ZrO2, Li2SiO3, Li3PO4


t-ZrO2 crystal size
≤2 μm





TSinter/° C.






tSinter/min.






main cryst. phase






other cryst. phase






Tpress/° C.






tpress/° C.






heating rate K/min






main cryst. phase






other cryst. phase






σB/Mpa
 >300

777 ± 101



L*
60-95





a*
−1-12





b*
 1-35





CR
65-85





Klc (SEVNB)
>2





Klc (Vickers)
>2





Klc (Chevron notch)
≥3





CTE/1*10−6K−1(25° C.-500° C.)
 8-13





chem. Solubility (acetic
 0-99





acid/μg*cm−2














Example No.
Ideal range
25
26
27





Oxide mol %






SiO2
55-65
58.6
58.6
63.1


Li2O
22-32
27.8
27.8
30.0


CaO
 0-10





MgO
 0-10
3.0
3.0



SrO
0-5





ZnO
0-5





Na7O
0-5


1.4


K2O
0-5





Cs2O
0-2





Rb2O
0-2





Al2O3
0-5
0.6
0.6



B7O3
0-5





Y7O3
0-3





La2O3
0-3





In2O3
0-1





Ga2O3
0-1





Bi2O3
0-1





ZrO7
 5-10
8.0
8.0
4.0


TiO7
0-2





CeO2
0-1





SnO2
0-2





MnO2
0-2

0.5



P2O5
0-5
1.5
1.5
1.5


Nb7O5
0-1





Ta2O5
0-1





V2O5

0-0.5






MoO3
0-2
0.5




WO3
0-2





GeO2
0-5





F-
0-1





Σ
  100
100.0
100.0
100.0


SiO2/Li2O
1.8-3
2.11
2.11
2.10


Tg/° C.
450-600
533
518
477


Tmelt/° C.
1200-1600
1450
1450
1450


tmelt/min.
 5-120
120
120
120


Tnucleation/° C.
450-600
570
560
500


tnucleation/min
 5-120
30
30
30


TC1/° C.
800-900
800
870
880


tC1/min
 5-120
60
60
60


heating rate K/min
 5-140
30
30
30


RT-XRD






main cryst. phase
Li2Si2O5
Li2Si2O5
Li2Si2O5
Li2Si2O5


other cryst. phase
t-ZrO2, Li3PO4
t-ZrO2, m-ZrO2, Li3PO4
Zektzerite, m-ZrO2, t-
Li2SiO3, Li3PO4,





ZrO2, Li2SiO3, Li3PO4
Cristobalite


t-ZrO2 crystal size
≤2 μm





TSinter/° C.






tSinter/min.






main cryst. phase






other cryst. phase






Tpress/° C.






tpress/° C.






heating rate K/min






main cryst. phase






other cryst. phase






σB/Mpa
 >300





L*
60-95





a*
−1-12





b*
 1-35





CR
65-85





Klc (SEVNB)
>2





Klc (Vickers)
>2





Klc (Chevron notch)
≥3





CTE/1*10−6K−1(25° C.-500° C.)
 8-13





chem. Solubility (acetic
 0-99





acid)/μg*cm−2













Example No.
Ideal range
28
29





Oxide mol %





SiO2
55-65
59.4
63.5


Li2O
22-32
28.2
27.6


CaO
 0-10




MgO
 0-10




SrO
0-5




ZnO
0-5




Na2O
0-5
1.4
1.4


K2O
0-5




Cs2O
0-2




Rb2O
0-2




Al2O3
0-5




B7O3
0-5




Y2O3
0-3




La2O3
0-3




In2O3
0-1




Ga7O3
0-1




Bi2O3
0-1




ZrO2
 5-10
9.5
6.0


TiO2
0-2




CeO2
0-1




SnO2
0-2




MnO2
0-2




P7O5
0-5
1.5
1.5


Nb2O5
0-1




Ta2O5
0-1




V2O5

0-0.5





MoO3
0-2




WO3
0-2




GeO2
0-5




F-
0-1




Σ
  100
100.0
100.0


SiO2/Li2O
1.8-3
2.11
2.30


Tg/° C.
450-600
536
512


Tmelt/° C.
1200-1600
1450
1450


tmelt/min.
 5-120
120
120


Tnucleation/° C.
450-600
560
530


tnucleation/min
 5-120
30
30


TC1/° C.
800-900
960
800


tC1/min
 5-120
60
60


heating rate K/min
 5-140
30
30


RT-XRD





main cryst. phase
Li2Si2O5
Zektzerite
Li2Si2O5


other cryst. phase
t-ZrO2, Li3PO4
Li2SiO3, Li3PO4, t-ZrO2,
Li3PO4, Cristobalite




m-ZrO2



t-ZrO2 crystal size
≤2 μm




TSinter/° C.





tSinter/min.





main cryst. phase





other cryst. phase





Tpress/° C.





tpress/° C.





heating rate K/min





main cryst. phase





other cryst. phase





σB/Mpa
 >300




L*
60-95




a*
−1-12




b*
 1-35




CR
65-85




Klc (SEVNB)
>2




Klc (Vickers)
>2




Klc (Chevron notch)
≥3




CTE/1*10−1K−1(25° C.-500° C.)
 8-13




chem. Solubility (acetic
 0-99




acid)/μg*cm−2
























TABLE 3





Example No.
ideal range
H1
H2
H3
H4
H5
H6
H7























Oxide mol %










SiO2
55-65
60.0
60.0
61.0
60.5
64.2
60.0
58.0


Li2O
22-32
28.5
28.5
28.5
28.0
24.0
28.0
28.0


CaO
 0-10






1.8


MgO
 0-10
1.5
1.5
2.0
3.0





SrO
0-5









ZnO
0-5









Na2O
0-5




1.0

1.0


K2O
0-5






0.3


Cs2O
0-2




1.5




Rb2O
0-2





1.5



Al2O3
0-5


0.6
0.6

0.6
0.5


B2O3
0-5









Y2O3
0-3






0.2


La7O3
0-3



0.1





In2O2
0-1









Ga2O3
0-1









Bi2O3
0-1









ZrO2
 5-10
8.0
8.0
6.0
6.0
7.5
7.0
8.0


TiO2
0-2









CeO2
0-1









SnO2
0-2









MnO2
0-2









P2O5
0-5
1.5
1.5
1.6
1.6
1.8
1.6
2.0


Nb2O5
0-1





0.3



Ta2O5
0-1
0.5
0.5
0.3
0.2


0.2


V2O5

0-0.5










MoO3
0-2









WO3
0-2









GeO2
0-5





1.0



F-
0-1









Σ
100
100.0
100.0
100.0
100.0
100.0
100.0
100.0


SiO2/Li2O
1.8-3
2.11
2.11
2.14
2.16
2.68
2.14
2.07


Tg/° C.
450-600









Tmelt/° C.
1200-1600
1450
1450
1450
1450
1450
1450
1450


tmelt/min.
 5-120
120
120
120
120
120
120
120


Tnucleation/° C.
450-600
560
560
550
550
560
550
550


tnucleation/min
 5-120
30
30
20
20
30
20
20


TC1/° C.
800-900
840
850
830
850
850
830
820


tC1/min
 5-120
60
120
40
15
90
40
60


heating rate K/min
 5-140
30
30
30
30
30
30
30


RT-XRD










main cryst. phase
Li2Si2O5
Li2Si2O5
Li2Si2O5
Li2Si2O5
Li2Si2O5
Li2Si2O5
Li2Si2O5
Li2Si2O5,










Li2SiO3


other cryst. phase
  t-ZrO2,
m-ZrO2,
m-ZrO2,
t-ZrO2,
t-ZrO2,
t-ZrO2,
t-ZrO2,
t-ZrO2,



Li3PO4
t-ZrO2,
t-ZrO2,
Li3PO4
Li3PO4
Li3PO4,
Li3PO4
Li3PO4




Li3PO4,
Li3PO4,







σg/Mpa
 >300
>400
>400
>400
>400
>400
>400
>400


L*
60-95









a*
−1-12









b*
 1-35









CR
65-85
80

76
70
82
78
90


Klc (SEVNB)
>2


>2.5
>2
3
>2.5
>2


Klc (Vickers)
>2




3.5
3.0
>2.5


Klc (Chevron notch)
≥3 
≥3
≥4
≥3
≥3
≥4
≥3.5
≥3


CTE/1*10−6K−1(25° C.-500° C.)
 8-13
8-13
8-13
8-13
8-13
8-13
8-13
8-13


chem. Solubility (acetic
 0-99
<100
<100
<100
<100
<100
<100
<100


acid)/μg*cm3









In some embodiments, the glass precursor and/or the glass ceramic can be strengthened to include compressive stress (CS) that extends from a surface thereof to a depth of compression (DOC). The compressive stress regions are balanced by a central portion exhibiting a tensile stress. At the DOC, the stress crosses from a positive (compressive) stress to a negative (tensile) stress. In one or more embodiments, the glass article may be chemically strengthened by ion exchange or other methods known in the art. In some embodiments, the residual glass phase or the glass precursor to the glass ceramic comprises at least one of lithium, sodium or potassium, which enables ion exchange. Ion exchange is commonly used to chemically strengthen glasses. In one particular example, alkali cations within a source of such cations (e.g., a molten salt, or “ion exchange,” bath) are exchanged with smaller alkali cations within the glass to achieve a layer under a compressive stress (CS) extending from the surface of the glass to a depth of compression (DOC) within the glass phase. For example, potassium ions from the cation source are often exchanged with sodium and/or lithium ions within the glass phase, and the K+ concentration profile correlates with the compressive stress and depth of layer.


The glass ceramic or precursor glass may be ion exchanged by immersion in at least one ion exchange bath containing molten salts (e.g., nitrates, sulfides, halides, or the like) of at least one alkali metal such as lithium, sodium, or potassium. The ion exchange bath may contain a salt (or salts) of a single alkali metal (e.g., sulfides, nitrates, or halides of Li, Na, or K) or salts of two or more alkali metals (e.g., sulfides, nitrates, or halides of Li and Na, or sulfides, nitrates, or halides of Na and K). Ion exchange is carried out in the ion exchange bath at temperatures ranging from about 390° C. to about 550° C. for times ranging from about 0.5 hour to about 24 hours


The precursor glass or glass ceramic, in some embodiments, is ion exchanged and has a compressive layer extending from a surface to a depth of compression (DOC) of at least about 10 μm or, in some embodiments, at least about 30 μm into the glass ceramic. In some embodiments, the compressive layer extends from the surface of the precursor glass or glass ceramic to a depth of up to about 20% of the longest dimension of the glass ceramic. In some embodiments, the precursor glass or glass ceramic may be strengthened to exhibit a surface compressive stress in a range from about 250 MPa to about 800 MPa.


In the strengthened glass ceramic, the depth of the compressive layer may be determined by electron microprobe, glow-discharge optical emission spectroscopy (GDOES), which is a technique for measuring depth profiles of constituent elements in a solid sample by detecting emissions from atoms accommodated in plasma by sputtering), or similar techniques that can provide composition data as a function of depth, where data would show incorporation of Na (where Na+ replaces Li+ in the glass phase) and/or K at the surfaces. The DOC of a precursor glass may be measured by surface stress meter (FSM) using commercially available instruments such as the FSM-6000, manufactured by Orihara Industrial Co., Ltd. (Japan). Surface stress measurements rely upon the accurate measurement of the stress optical coefficient (SOC), which is related to the birefringence of the glass. SOC in turn is measured by those methods that are known in the art, such as fiber and four point bend methods, both of which are described in ASTM standard C770-98 (2013), entitled “Standard Test Method for Measurement of Glass Stress-Optical Coefficient,” the contents of which are incorporated herein by reference in their entirety, and a bulk cylinder method. CS may also be measured by FSM. As used herein CS may be the “maximum compressive stress” which is the highest compressive stress value measured within the compressive stress layer. In some embodiments, the maximum compressive stress is located at the surface of the precursor glass or glass ceramic. In other embodiments, the maximum compressive stress may occur at a depth below the surface, giving the compressive profile the appearance of a “buried peak.”


The ZrO2-toughened glass-ceramic materials described herein have fracture toughness values, as measured by Chevron notch short bar methods known in the art and described in ASTM procedure E1304-97, of at least about 2 MPa·m1/2, in some embodiments, at least about 3 MPa·m1/2, and in still other embodiments, at least about 4 MPa·m1/2. In some embodiments, the fracture toughness is equal to or greater than 3.5 MPa·m1/2. In some embodiments, the fracture toughness is between about 5 to 10 MPa·m1/2. In some embodiments, the fracture toughness is between about 2 to 10 MPa·m1/2. In some embodiments, the fracture toughness is in a range from about 2 MPa·m1/2, or from about 3 MPa·m1/2, or from about 4 MPa·m1/2 to about 10 MPa·M1/2 or any range there between and, in other embodiments, from about 2 MPa·m1/2, or from about 3 MPa·m1/2, or from about 4 MPa·m1/2 to about 8 MPa·m1/2, or any range there between. Results of fracture toughness and flex strength measurements for selected samples are provided in Table 1-3. Examples 5-12 in Table 1-3 illustrate the increase in fracture toughness with increasing amounts of ZrO2.


In some embodiments, the glass ceramics have a biaxial flexural strength of at least 700 MPa. In some embodiments, the glass ceramics have a biaxial flexural strength equal to or greater than 300 MPa. In some embodiments, the glass ceramics have a biaxial flexural strength equal to or greater than 500 MPa. The biaxial flexural strength can be measured by methods known in the art. In an embodiment, the biaxial flexural strength is measured according to ISO 6872.


In some embodiments, the glass ceramics above further comprise a coloring component. The coloring component may comprise, for example, V2O5, Cr2O3, TiO2, CeO2, MnO2, NiO, CuO, Co3O4, rare earth oxides, and combinations thereof. In some cases, the total wt % of coloring component is from >0 to about 4 wt %.


The glass ceramics of one or more embodiments may exhibit a substantially white, “pearl,” milky, or white-translucent color. In some embodiments, the glass ceramics exhibit a color presented in CIELAB color space coordinates determined from reflectance spectra measurements using a spectrophotometer, with illuminant D65 and specular reflectance excluded, of the following ranges: a*=from about −1 to about +3; b*=from about −7 to about +3; and L*>85.


The glass ceramics of one or more embodiments may exhibit a contrast ratio (CR) of 60 to 95. In some embodiments, the glass ceramics exhibit a contrast ratio of 70 to 85, 70 to 90, 75 to 85, 75 to 90, 75 to 95, 80 to 90, or 80 to 95. In an embodiment, the glass ceramics exhibit a contrast ratio of 75. The contrast ratio can be measured by methods known in the art. In an embodiment, the contrast ratio is measured according to British Standard BS6512 using samples of 2 mm thickness.


The glass ceramics may have a desirable chemical solubility. In some embodiments, the glass ceramics have a chemical solubility of equal to or less than 100 μg/cm2. In some embodiments, the glass ceramics have a chemical solubility of equal to or less than 2000 μg/cm2, which particularly well suited for dental articles that are frameworks for a dental restoration. Chemical solubility can be measured by methods known in the art. In an embodiment, chemical solubility is measured according to dental standard ISO6872-2015.


The materials described herein are particularly useful because of the ability to partially ceram to the metasilicate phase, machine and/or finish and then ceram to the full high fracture toughness material. When ceramming, metasilicate comes out first allowing for shaping or machining, then further ceramming to get t-ZrO2/LDS phases. In some embodiments, the ZrO2-toughened glass ceramic described herein is used in applications such as, but not limited to valves, blades, cutting tools, knives, components for semiconductor manufacturing (cover rings, etch nozzles, RF shields, etc.), oil and gas drilling components (downhole pump plungers, control valves, etc.), and ferrules for optical fiber connectors, where high resistance to mechanical wear is desired.


In some embodiments, the ZrO2-toughened glass ceramic described herein is used in dental composites, restorative materials, and articles such as, but not limited to, fillings, bridges, splints, crowns, partial crowns, dentures, teeth, jackets, inlays, onlays, facings, veneers, facets, implants, cylinders, abutments and connectors. In addition to the glass ceramic, such dental composites, restorative materials, and articles may also include further additives such as, but not limited to, stabilizers, flavorings, colorants (e.g., Mn, V, Ti, Fe, Er, Co, Pr, Tb, Cr, Nd, Ce, V, Eu, Ho, Ni, and Cu, oxides and sulfides thereof, and combinations thereof), microbiocidal active ingredients, fluoride ion-releasing additives, optical brighteners, plasticizers, UV absorbers, and/or solvents such as water, ethanol, or corresponding solvent mixtures. The glass ceramic may be processed into the dental article using various methods including, but not limited to, injection molding, gel-casting, slip casting, or electroforming, hand forming, CAD/CAM methods, 3d printing, and other various rapid prototyping methods that are known in the art. The glass ceramic may, in some embodiments, be ground to powder, which may be then formed into a suspension, pellet, feedstock material or a pre-sintered blank prior being formed into the dental article.


In some embodiments, the glass ceramic or precursor glass is a pressable ingot suitable for forming a dental restoration. In some embodiments, the glass ceramic is in the form of a millable dental blank or disk.


Processes for Making Glass Ceramics and Glass Ceramic Precursors

Precursor glasses having the oxide contents in Tables 1-3 were formulated as follows. The batch materials were thoroughly mixed (for example, using a turbular mixer) in order to secure a homogeneous melt, and subsequently placed into silica and/or platinum crucibles. The crucibles were placed into a furnace and the glass batch was then melted and maintained at temperatures ranging from 1250−1650° C. for times ranging from about 1-16 hours. The melts were thereafter poured into steel molds to yield glass slabs having dimensions of approximately 7″×11″×½″. Subsequently, those slabs were transferred immediately to an annealer operating at about 450-650° C. Samples were held at this temperature for about 20-90 mins and subsequently cooled overnight. This step is a heat treatment for relaxation and parallel nucleation. In one non-limiting example, precursor glasses were prepared by dry blending the appropriate oxides, carbonates, and mineral sources for a time sufficient to thoroughly mix the ingredients. The glasses were melted in platinum crucibles at temperatures ranging from about 1100° C. to about 1650° C. and held at temperature for about 16 hours. The resulting glass melts was then poured onto a steel table to cool. The precursor glasses were then annealed at appropriate temperatures.


In one embodiment, glasses were melted (in platinum crucibles) at temperatures ranging from about 1100° C. to about 1650° C. and held at temperature for about 1 to about 16 hours. The resulting glass was poured into molds and subsequently, that molded glass was transferred immediately to an annealing furnace operating at about 450-650° C. Samples were held at this temperature for about 20-90 mins and subsequently cooled overnight. In some embodiments, the heating step between 450-650° C. is a heat treatment for relaxation of the glass ceramic. In some embodiments, the heating step between 450-650° C. is a heat treatment for nucleation of the glass ceramic. In some embodiments, the heating step between 450-650° C. is a heat treatment for relaxation and nucleation of the glass ceramic.


Once the glass compositions were made, the resulting precursor glasses were cerammed by heat treating. Heat treating is carried out under conditions that lead to crystallization of the glass composition to make a ceramic. Generally, this is done via a two-phase heating process wherein the glass is first heated to a lower temperature to induce nucleation, and then heated to a higher temperature to induce crystallization. Non-limiting conditions include first heating to 600° C. to 850° C., 635° C. to 800° C., or 650° C. to 750° C. for from 0.1 to 10 hours or from 2 to 8 hours (called a nucleation step), followed by heating at 725° C. to 1000° C., 725° C. to 950° C., 725° C. to 900° C., or 750° C. to 850° C. for 0.1 to 8 hours or 2 to 4 hours (a crystal growth step).


For example, a precursor glass comprising at least about 18 wt % Li2O, up to about 5 wt % Al2O3, and at least about 4 wt % ZrO2 is first provided. In some embodiments, the precursor material may comprise a precursor glass and a ceramic powder, wherein the ceramic powder comprises ZrO2. In this embodiment, the precursor glass may be ground to a powder having an average grain size of less than about 10 μm and then mixed with the ceramic powder. The glass ceramic may then, in some embodiments, be sintered at temperatures ranging from about 650° C. to about 800° C. for a time ranging from about 0.5 hour up to about 4 hours. In other embodiments, the glass ceramic may be hot pressed to form a near-net shape.


The precursor material is next heat-treated or “cerammed” to form the glass ceramic. The ceramming step comprises first heating the precursor material at a first temperature in a range from about 600° C. to about 750° C. for a first time period ranging from about 15 minutes to about 2.5 hours or, in some embodiments, from about 15 minutes to about one hour or, in other embodiments, from about 1.5 hours to about 2.5 hours. Following the first heating step, the material is heated at a second temperature in a range from about 775° C. to about 1125° C. for a second time period ranging from about 0.5 hour to about 5 hours, or, in some embodiments, from about 0.5 hour to about 5 hours or, in other embodiments, from about 3 hours to about 5 hours to form the glass ceramic.


In some embodiments, the ceramming step comprises first heating the precursor material at a first temperature in a range from about 600° C. to about 750° C. for a first time period ranging from about 15 minutes to about 2.5 hours or, in some embodiments, from about 15 minutes to about one hour or, in other embodiments, from about 1.5 hours to about 2.5 hours. Following the first heating step, the material is heated at a second temperature in a range from about 820° C. to about 900° C. or 840° C. to about 900° C. for a second time period ranging from about 0.5 hour to about 5 hours, or, in some embodiments, from about 0.5 hour to about 5 hours or, in other embodiments, from about 3 hours to about 5 hours to form the glass ceramic.


In some embodiments, the method of making a glass ceramic with a residual glass phase, a tetragonal ZrO2 phase dispersed throughout the residual glass phase, and at least one of a crystalline lithium disilicate phase comprises the steps of providing a precursor material, ceramming the precursor material to form the glass ceramic, wherein ceramming comprises heating the precursor material at a first temperature for a first time period of from about 5 minutes to about 2 hours, followed by heating to a second temperature for a second time period of from about 5 minutes to 2 hours, where the first temperature is in a range from about 450° C. to about 750° C. and the second temperature is in a range from about 800° C. to about 900° C. In some embodiments, the first time period is from about 15 minutes to about 1 hour. In some embodiments, the second time period is from about 15 minutes to about 1 hour. In some embodiments, the second temperature is in a range from about 820° C. to about 870° C.


In some embodiments, the method described are used to make a glass ceramic powder, glass ceramic ingot, glass ceramic block, glass ceramic disk, or glass ceramic block.


While in some embodiments ZrO2-toughened glass-ceramics have been made by adding ZrO2 particles to a powdered glass-ceramic precursor glass, with subsequent sintering, such methods involve mixing of two dissimilar powders, which can lead inhomogeneity in the final ZrO2-glass-ceramic product. In addition, the sintering times and temperatures that are used may promote more grain growth than desired or may have other detrimental effects on microstructure. In the sintering method, nucleation and growth of the desired phases may be a mixture of surface and bulk nucleation, thereby resulting in microstructures that are difficult to control or repeat. All of these experimental challenges could result in compromised strength and/or fracture toughness values of the final material. Furthermore, sintering is often done at elevated pressures in an attempt to reach full density of the final product. Achieving full density may or may not be achieved and porosity may be an issue for realizing high strength and fracture toughness materials. Producing ZrO2-containing glass ceramics from homogeneous (i.e., statistically isotropic distribution of the glass components) glass precursors, as described herein, addresses many of the above experimental issues. The glasses may be homogeneously nucleated and the nucleation and growth steps can be further controlled to yield final products with optimized microstructures and phase assemblages. Full density is achieved through the ceramming of the dense precursor glass without the use of elevated pressure. Precursor glasses are produced by conventional glass melting and forming techniques. Whereas some glass compositions containing high amounts of ZrO2 must be melted at high temperature, many of the Li2O and MgO-containing compositions described herein are easily melted at low temperatures (e.g., <1650° C.).


Additional phases, previously described hereinabove such as lithium metasilicate, lithium disilicate, β-quartz solid solution, β-spodumene solid solution, may also be precipitated in the glass ceramic. In some embodiments, these microstructures and phase assemblages are not easily obtainable using ceramic processing routes.


In some instances, the glass ceramic may be difficult to machine or otherwise form into a finished or near-net shape once cerammed. Thus the method described herein may also include machining and/or otherwise shaping (e.g., molding or casting) the glass ceramic prior to ceramming or, in some embodiments, after partial ceramming; i.e., following ceramming at the first temperature and prior to ceramming at the second temperature. Benefits in manufacturing may be realized where the precursor glasses can be made using conventional glass melting and forming techniques. Heat treatments of the glasses are accomplished at modest temperatures that are consistent with typical glass-ceramic manufacturing techniques. Large amounts of the desired tetragonal ZrO2 phase may repeatably be formed, since the ZrO2 is dissolved in the glass phase and the heat treatments that precipitate the ZrO2 are performed at temperatures that do not cause significant formation of the monoclinic ZrO2 phase, thereby enabling the toughening described herein.


The glass ceramics and precursor glasses described herein are easily cast or rolled as homogeneous glasses, and final geometries such as sheets or boules are obtainable. The resultant glass ceramic can be provided as a sheet, which can then be reformed by pressing, blowing, bending, sagging, vacuum forming, or other means into curved or bent pieces of uniform thickness. Reforming can be done before thermally treating or the forming step can also serve as a thermal treatment step where both forming and thermally treating are performed substantially simultaneously.


The following examples are presented to illustrate the present disclosure. They are not intended to limiting in any matter.


Example 1


FIGS. 1A and 1B are scanning electron microscopy (SEM) images showing embodied glass ceramics having ZrO2 and other phases present in samples. FIG. 1a is an image of a glass ceramic material (composition example 6 in Table 1) that was cerammed by first heating at 750° C. for 2 hours and then heating at 900° C. for 4 hours, and FIG. 1b is an image of a glass ceramic material (composition example 10 in Table 1) that was cerammed by first heating at 800° C. for 2 hours and then heating at 900° C. for 4 hours. The microstructure of the materials in both images is homogeneous. The dark gray rods 120 in FIGS. 1A and 1B are lithium disilicate and the white phases 110 in FIGS. 1a and 1b are ZrO2. The ZrO2 grains 110 are on the order of about 1 μm in size. X-Ray diffraction studies of these samples reveals that the zirconia phase is primarily tetragonal ZrO2. The sample that was cerammed at 900° C. (FIG. 1B) appears by SEM to contain a higher amount of the tetragonal ZrO2 phase than the sample cerammed at 800° C. for 4 hours (FIG. 1A).


Example 2


FIGS. 2A-D are SEM images of an indented area on the surface of a glass ceramic (composition example 6 in Table 1) that was cerammed by first heating at 700° C. for 2 hours and then heating at 900° C. for 4 hours, showing a crack (area 100 in FIGS. 2A-D) at different magnifications (FIG. 2A at 500× magnification; FIG. 2B at 1000×; FIG. 2C at 10,000×; FIG. 2D at 50,000×). Under indentation load of 50 kgf, the sample exhibited crack deflection and tortuous crack path which are indicative of toughening mechanisms.


Example 3


FIG. 3 is a plot in which ring-on-ring (ROR) data obtained for 1 mm-thick samples of a ZrO2-toughened glass ceramic (composition sample 8 in Table 1, cerammed by first heating at 700° C. for 2 hours and then heating at 850° C. for 4 hours) of the present disclosure are compared to that of a glass ceramic comprised of mostly β-spodumene with a fracture toughness of 0.88 MPa*m1/2 and of the same thickness. The ring-on-ring test is a flexural strength measurement known in the art for testing flat glass and glass ceramic specimens and is described in ASTM C1499-09(2013), entitled “Standard Test Method for Monotonic Equibiaxial Flexural Strength of Advanced Ceramics at Ambient Temperature.” ASTM C1499-09(2013) serves as the basis for the ring-on-ring test methodology described herein. In some instances, the glass ceramic samples were abraded prior to ring-on-ring testing with 15 grit silicon carbide (SiC) particles that are delivered to the glass sample using the method and apparatus described in Annex A2, entitled “abrasion Procedures,” of ASTM C158-02 (2012), entitled “Standard Test Methods for Strength of Glass by Flexure (Determination of Modulus of Rupture). The contents of ASTM C1499-09(2013) and ASTM C158-02(2012), Annex 2, are incorporated herein by reference in their entirety. As seen in FIG. 3, the ZrO2-toughened glass ceramic (A in FIG. 3) exhibits a higher load-to-failure than the β-spodumene glass ceramic (B in FIG. 3).


Example 4


FIG. 4 is a Weibull plot in which abraded and non-abraded ring-on-ring (ROR) data obtained for 1 mm-thick ion-exchanged ZrO2-toughened glass ceramic samples (composition sample 8 in Table 1, which was cerammed by first heating at 700° C. for 2 hours and then heating at 850° C. for 4 hours) of the present disclosure are compared to that of a β-spodumene glass-ceramic of the same thickness. The samples included: non-abraded composition sample 8 in Table 1 that was ion-exchanged at 470° C. for 4 hours in an ion exchange bath containing 60% KNO3 and 40% NaNO3 by weight (D2 in FIG. 4); abraded composition sample 8 in Table 1 that was ion-exchanged ion-exchanged at 470° C. for 4 hours in an ion exchange bath containing 60% KNO3 and 40% NaNO3 by weight, abraded at 15 psi (D1 in FIG. 4); non-abraded β-spodumene glass ceramic samples that were ion-exchanged at 430° C. for 4 hours in a NaNO3 ion exchange bath (C1 in FIG. 4); and β-spodumene glass ceramic samples that were ion-exchanged at 430° C. for 4 hours in a NaNO3 ion exchange bath, abraded at 15 psi (C2 in FIG. 4). As seen in FIG. 4, the load-to-failure observed for ion-exchanged ZrO2-toughened glass ceramic samples was less than that observed for the ion-exchanged β-spodumene glass ceramic samples.


The glass ceramic materials in Table 2-3 were prepared and characterized as follows:


A) Examples (1-14, 17, 18, 20-22, 24): crystal phase analysis


1. Melting glass from raw materials in Pt—Rh crucible


2. Casting glass-melt into water (glass frit)


3. Drying glass-frit at approx. 150° C. for approx. 60 min


4. DSC measurement of the glass granules


5. remelting glass frit and casting glass melt into graphite mold


6. transferring glass block into pre-heated muffle furnace: relaxation and nucleation heat treatment (Tnucleation/tnucleation)


7. preparing small disc shaped glass samples from the glass block (sawing)


8. crystallization heat treatment of the base glass samples in Programat furnace (TC,tc)


9. removing the surface layer of the crystallized glass-ceramic samples by means of grinding


10. XRD analysis


B) Examples 3, 13, 17: color and translucency


1. Melting glass from raw materials in Pt—Rh crucible


2. Casting glass-melt into water (glass frit)


3. Drying glass-frit at approx. 150° C. for approx. 60 min


4. DSC measurement of the glass granules


5. remelting glass frit and casting glass melt into graphite mold


6. transferring glass block into pre-heated muffle furnace: relaxation and nucleation heat treatment (Tnucleation-tnucleation)


7. preparing small disc shaped glass samples from the glass block (sawing)


8. crystallization heat treatment of the base glass samples in Programat furnace (TC,tc)


9. preparation of the crystallized glass-ceramic for CR/color measurement according to British Standard BS5612


C) Example 16: hot molding (pressing)


1. Melting glass from raw materials in Pt—Rh crucible


2. Casting glass-melt into water (glass frit)


3. Drying glass-frit at approx. 150° C. for approx. 60 min


4. DSC measurement of the glass granules


5. remelting glass frit and casting glass melt into steel mold


6. transferring glass ingots into pre-heated muffle furnace: relaxation and nucleation heat treatment (Tnucleation/tnucleation)


7. processing glass ingots via Ivoclar pressing technology: Tpress/tpress

8. preparation of pressed glass-ceramic for CR/color measurement according to BS5612


9. CR/color measurement


10. XRD analysis


D) Examples 1, 3, 4: KIc

1. Melting glass from raw materials in Pt—Rh crucible


2. Casting glass-melt into water (glass frit)


3. Drying glass-frit at approx. 150° C. for approx. 60 min


4. DSC measurement of the glass granules


5. remelting glass frit and casting glass melt into graphite mold


6. transferring glass blocks into pre-heated muffle furnace: relaxation and nucleation heat treatment (Tnucleation/tnucleation)


7. processing glass ingots via Ivoclar pressing technology: Tpress/tpress

8. crystallization heat treatment of the base glass samples in Programat furnace (TC,tc)


9. Preparation of samples for KIc test (SEVNB method) according to dental standard ISO6872-2015


10. KIc measurement


E) Examples 3, 6: chemical solubility


1. Melting glass from raw materials in Pt—Rh crucible


2. Casting glass-melt into water (glass frit)


3. Drying glass-frit at approx. 150° C. for approx. 60 min


4. DSC measurement of the glass granules


5. remelting glass frit and casting glass melt into graphite mold


6. transferring glass block into pre-heated muffle furnace: relaxation and nucleation heat treatment (Tnucleation-tnucleation)


7. preparing disc shaped test specimen for biaxial strength measurements via wet milling (CAD/CAM)


8. crystallization heat treatment of the base glass samples in Programat furnace (TC,tc)


9. preparation of the sample surface for chemical solubility test according to dental standard ISO6872-2015


10. measurement of chemical solubility in acetic acid


F) Example 23: biaxial flexural strength


1. Melting glass from raw materials in Pt—Rh crucible


2. Casting glass-melt into water (glass frit)


3. Drying glass-frit at approx. 150° C. for approx. 60 min


4. DSC measurement of the glass granules


5. remelting glass frit and casting glass melt into graphite mold


6. transferring glass block into pre-heated muffle furnace: relaxation and nucleation heat treatment (Tnucleation-tnucleation)


7. preparing disc shaped test specimen for biaxial strength measurements via wet milling (CAD/CAM)


8. crystallization heat treatment of the base glass samples in muffle furnace (TC,tc)


9. preparation of the sample surface for biaxial flexural test according to dental standard ISO6872-2015


10. measurement of biaxial flexural strength


G) Examples 15, 19: sintering


1. Melting glass from raw materials in Pt—Rh crucible


2. Casting glass-melt into water (glass frit)


3. Drying glass-frit at approx. 150° C. for approx. 60 min


4. DSC measurement of the glass granules


5. Production of glass powder using a mortar mill (grain size <45 μm)


6. Production of a powder compact via pressing of glass powder


7. Sintering (including parallel nucleation and crystallization heat treatment) of the powder compact in a Programat furnace (TC,tc)


8. XRD analysis


While typical embodiments have been set forth for the purpose of illustration, the foregoing description should not be deemed to be a limitation on the scope of the disclosure or appended claims. Accordingly, various modifications, adaptations, and alternatives may occur to one skilled in the art without departing from the spirit and scope of the present disclosure or appended claims.

Claims
  • 1. A glass ceramic or precursor glass comprising at least about 50 mol % SiO2, at least about 20 mol % Li2O, up to about 5 mol % Al2O3, and at least about 4 mol % ZrO2, wherein the glass ceramic comprises a tetragonal ZrO2 phase, a crystalline lithium disilicate phase, and a residual glass phase, and wherein the glass ceramic has a contrast ratio of at least 60, and the lithium disilicate is the predominant crystalline phase and the tetragonal ZrO2 phase is a minor crystalline phase.
  • 2. (canceled)
  • 3. (canceled)
  • 4. (canceled)
  • 5. (canceled)
  • 6. The glass ceramic of claim 1, wherein the glass ceramic comprises about 5 to 60 vol % lithium disilicate and 1 to 20 vol % tetragonal ZrO2 phase.
  • 7. (canceled)
  • 8. (canceled)
  • 9. (canceled)
  • 10. (canceled)
  • 11. The glass ceramic of claim 1, wherein the crystal size of the tetragonal ZrO2 phase is between 0.1 to 10 μm
  • 12-19. (canceled)
  • 20. The glass ceramic of claim 1, wherein the glass ceramic has a contrast ratio of 60 to 90.
  • 21. The glass ceramic of claim 1, wherein the glass ceramic has a fracture toughness of at least 3 MPa·m1/2.
  • 22. (canceled)
  • 23. (canceled)
  • 24. (canceled)
  • 25. The glass ceramic of claim 1, wherein the glass ceramic has a biaxial flexural strength equal to or greater than 300 MPa.
  • 26. (canceled)
  • 27. (canceled)
  • 28. The glass ceramic of claim 1, wherein the glass ceramic has a chemical solubility equal to or less than 2000 μg/cm2.
  • 29. (canceled)
  • 30. The glass ceramic of claim 1, wherein the glass ceramic comprises 5.5-8.5 mol % ZrO2.
  • 31. (canceled)
  • 32. (canceled)
  • 33. (canceled)
  • 34. The glass ceramic of claim 1, wherein the SiO2:Li2O ratio is between about 1.8 to 3.0.
  • 35. (canceled)
  • 36. (canceled)
  • 37. (canceled)
  • 38. (canceled)
  • 39. The glass ceramic of claim 1, wherein the glass ceramic comprises: from about 50 mol % to about 75 mol % SiO2; from 0 mol % to about 5 mol % Al2O3; from about 20 mol % to about 40 mol % Li2O; from 0 mol % to about 5 mol % Na2O; from 0 mol % to about 5 mol % of at least one alkaline earth oxide; from 0 mol % to about 5 mol % of at least one rare earth oxide; from about 4 mol % to about 15 mol % ZrO2.
  • 40. The glass ceramic of claim 39, wherein the glass ceramic comprises at least one of: from 0 mol % to about 5 mol % MgO; from 0 mol % to about 1 mol % Y2O3; from 0 mol % to about 5 mol % CeO2; and from 0 mol % to about 10 mol % TiO2.
  • 41. The glass ceramic of claim 1, wherein the glass ceramic comprises less than 2 mol % Al2O3.
  • 42. The glass ceramic of claim 1, wherein the wherein the glass ceramic further comprises at least one of a monoclinic ZrO2 phase and a cubic ZrO2 phase.
  • 43. The glass ceramic of claim 1, wherein the glass ceramic further comprises a monoclinic ZrO2 phase, and wherein (tetragonal-ZrO2 (wt %)/monclinic-ZrO2 (wt %))≥2.
  • 44-50. (canceled)
  • 51. A glass ceramic comprising a tetragonal ZrO2 phase, a crystalline lithium disilicate phase, and a residual glass phase, wherein the glass ceramic comprises: from about 50 mol % to about 75 mol % SiO2; from 0 mol % to about 5 mol % Al2O3; from about 20 mol % to about 40 mol % Li2O; from 0 mol % to about 5 mol % Na2O; from 0 mol % to about 5 mol % of at least one alkaline earth oxide; from 0 mol % to about 5 mol % of at least one rare earth oxide; from about 4 mol % to about 15 mol % ZrO2.
  • 52-71. (canceled)
  • 72. The glass ceramic of claim 51, wherein the glass ceramic forms at least a portion of a dental composite, a dental restorative, or a dental article.
  • 73. The glass ceramic of claim 51, wherein the dental article is one of a filling, a bridge, a splint, a crown, a partial a crown, a denture, a tooth, a jacket, an inlay, an onlay, a facing, a veneer, a facet, an implant, a cylinder, an abutment, framework or a connector.
  • 74. A method of making a glass ceramic, the glass ceramic comprising a residual glass phase, a tetragonal ZrO2 phase dispersed throughout the residual glass phase, and at least one of a crystalline lithium disilicate phase, the method comprising the steps of: a. providing a precursor material, the precursor material comprising at least about 20 mol % Li2O, between about 55-65 mol % SiO2, and at least about 5 mol % ZrO2,b. ceramming the precursor material to form the glass ceramic, wherein ceramming comprises heating the precursor material at a first temperature for a first time period of from about 5 minutes to about 2 hours, followed by heating to a second temperature for a second time period of from about 5 minutes to 2 hours, wherein the first temperature is in a range from about 450° C. to about 750° C. and the second temperature is in a range from about 800° C. to about 900° C.
  • 75-81. (canceled)
  • 82. The method of claim 74, further comprising the steps nucleation, crystallization and sintering of the precursor glass powder.
  • 83. (canceled)
  • 84. (canceled)
  • 85. (canceled)
  • 86. The method of claim 74, further comprising machining or shaping the glass precursor material following heating the precursor material at the first temperature and prior to heating the precursor material at the second temperature.
  • 87. (canceled)
CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Application Nos. 62/512,418 filed on May 30, 2017, 62/361,210 filed on Jul. 12, 2016, and 62/354,271 filed on Jun. 24, 2016, the entire disclosures of which applications are hereby incorporated herein by reference.

PCT Information
Filing Document Filing Date Country Kind
PCT/US2017/039281 6/26/2017 WO 00
Provisional Applications (3)
Number Date Country
62354271 Jun 2016 US
62361210 Jul 2016 US
62512418 May 2017 US