Fracture toughness of glass

Abstract

A method of making glass is provided. The method comprises preparing a dispersion of a nano-material. A slurry of a glass matrix material is prepared. The nano-dispersion is mixed with the matrix slurry to form a nano-dispersion/slurry mixture. The nano-dispersion/slurry mixture is dried. The nano-dispersion/slurry mixture is pressed into a final manufacture comprising a molecular structure including the nano-material bonded within and uniformly distributed throughout the molecular structure. The manufacture comprises an increased fracture toughness compared with a conventional manufacture produced without bonding the nano-material within the molecular structure. The nano-material has a size on the order of tens of nanometers. The matrix material has a size on the order of several micrometers. Five percent of the nano-dispersion/slurry mixture comprises the nano-material dispersion. Sintering is performed on the final form using a sintering process following the pressing step. The sintering process includes a hot isostatic pressing process.

Description

FIELD OF THE INVENTION

The present invention relates to the field of materials science. More particularly, the present invention relates to glass manufactures and a novel method of making

BACKGROUND

In many applications, glass is utilized because of the desired properties such as transparency and light transmission. Many household products are made of glass and glass has many decorative functions. Glass is also used widely in buildings and automobiles just to name a few more applications. Glass can be reinforced with some kind of particulate matter. Composite glass is desirable since in addition to their high hardness the composite can also possess a greater fracture toughness, which includes the ability to resist fracture. Present methods used to produce composite glass are costly, inefficient and complicated.

Accordingly, it is desirable to create an efficient and inexpensive method to produce glass having improve material characteristics, and especially fracture toughness.

SUMMARY OF THE INVENTION

Other features of the present invention will become apparent from consideration of the following description taken in conjunction with the accompanying drawings.

A first aspect of the present invention is for a method of making glass is provided. The method comprises preparing a dispersion of a nano-material. A slurry of a glass matrix material is prepared. The nano-dispersion is mixed with the matrix slurry to form a nano-dispersion/slurry mixture. In one embodiment, the mixing includes pouring the matrix slurry into the nano-dispersion while agitating. Alternative, the mixing includes pouring the nano-dispersion into the matrix slurry while agitating. The nano-dispersion/slurry mixture is dried. The nano-dispersion/slurry mixture is pressed into a final manufacture comprising a molecular structure including the nano-material bonded within and uniformly distributed throughout the molecular structure. The manufacture comprises an increased fracture toughness compared with a conventional manufacture produced without bonding the nano-material within the molecular structure.

The method includes providing the nano-material with a size on the order of tens of nanometers before the dispersion preparing step. A micron sized matrix material is provided on the order of several micrometers before the slurry preparing step. One percent of the nano-dispersion/slurry mixture comprises the nano-material dispersion. Alternatively, 0.5-10.0 percent of the nano-dispersion/slurry mixture comprises the nano-material dispersion. In yet another alternative, 0.5-20.0 percent of the nano-dispersion/slurry mixture comprises the nano-material dispersion. Sintering is performed on the final form using a sintering process following the pressing step. The sintering process includes a hot isostatic pressing process. The manufacture includes the nano-material bonded at triple points of the molecular structure. The drying of the nano-dispersion/slurry mixture includes a spray drying process.

Other features of the present invention will become apparent from consideration of the following description taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The novel features of the invention are set forth in the appended claims. However, for purposes of explanation, several embodiments of the invention are set forth in the following figures.

FIG. 1 illustrates a plot of fracture toughness of a glass compared with a metal in accordance with an embodiment of the invention.

FIG. 2 illustrates a partial of a manufacture with improved fracture toughness in accordance with an embodiment of the invention.

FIG. 3 illustrates a method of making a glass with improved fracture toughness in accordance with an embodiment of the invention.

DETAILED DESCRIPTION

In the following description, numerous details and alternatives are set forth for the purpose of explanation. However, one of ordinary skill in the art will realize that the invention can be practiced without the use of these specific details. In other instances, well-known structures and devices are shown in block diagram form in order not to obscure the description of the invention with unnecessary detail.

Turning to FIG. 1, a plot 10 of fracture toughness of a glass compared with a metal is shown in accordance with an embodiment of the invention. Fracture toughness is a term in the field of material science that describes the characteristic of a material that has a crack to resist fracture. More specifically, fracture toughness describes a resistance of a material to a brittle fracture when a crack is present in the material. Brittle fracture occurs when the material exhibits no apparent plastic deformation prior to the fracture, in contrast to a ductile fracture, which is when the material exhibits extensive plastic deformation prior to the fracture. A glass will exhibit a low fracture toughness 12A while a metal will exhibit a significantly higher fracture toughness 12B. A novel method of the invention as described below produces a glass having an increased fracture toughness 12A′.

Hardness is a quality also shown in the plot of FIG. 1. Hardness is a term that describes the characteristic of a solid material to resist deformation. A metal will exhibit a low hardness 14A while a glass will exhibit a significantly higher hardness 14B.

Turning to FIG. 2, a partial of a manufacture 200 with improved fracture toughness is shown in accordance with an embodiment of the invention. The manufacture 200 comprises a composite of a glass matrix material 201 and nanoparticles or nano-material 206. The glass material 201 can comprise any a number of suitable glass materials depending on a particular application. In an exemplary embodiment the glass material 201 comprises a material from a group of silicon dioxide composites. A person of skill will appreciate the many possible oxides capable of combining with silicon dioxide to form the glass material. In one embodiment, the silicon dioxide composite can comprise silicon dioxide combined with a mixture of sodium carbonate, and either calcium carbonate or calcium oxide. In an alternative embodiment, the silicon dioxide composite can comprise silicon dioxide combined with boric oxide. In yet another embodiment, the silicon dioxide composite can comprise silicon dioxide combined with lead oxide.

Alternatively, the glass material 201 can comprise pure Silica or silicon dioxide (SiO2). In still another embodiment, the glass material can comprise a metallic glass. Examples of metallic glass alloys include alloys based on zirconium or palladium. The method as described in detail below produces the manufacture 200 in a final form that includes a “granular” or a molecular structure 204 having an amorphous disordered structure propagated throughout the manufacture 200. The molecular structure 204 comprises an average molecular boundary distance or diameter 208 of one to several micrometers. Preferably, the average molecular diameter 208 equals approximately one micrometer.

The nano-material 206 can comprise any a number of suitable materials that are non-miscible with the glass material 201 depending on a particular application. In an exemplary embodiment, the nano-material 206 can comprise a metallic material or a nano-metal. Examples of suitable metallic materials can include copper, silver and gold. A person of skill can appreciate that other metallic materials can also be suitable for the nano-material 206. Alternatively, the suitable metallic material can comprise a metallic compound. In an alternative embodiment, the nano-material 206 comprises a material from a group of non-oxide ceramics. Examples of suitable non-oxide ceramics can include titanium carbide or titanium diboride. In yet another embodiment, the nano-material 206 can comprise an oxide ceramic material that is non-miscible with the glass matrix material 201, for example, alumina and zirconia. A person of skill will appreciate an effect of the nano-material 206 on a refractive index and a transparent quality of the manufacture 200. Thus the nano-material 206 can be chosen such that refractive indexes of the nano-material 206 and the glass matrix material 201 are equal.

The novel method of the invention produces the manufacture 200 having nanoparticles 206 bonded within the molecular structure 204. The nanoparticles 206 are bonded within the molecular structure 204 of the glass material 201. A surface 202 of the manufacture 200 reveals that the nanoparticles 206 are substantially uniformly distributed throughout the molecular structure 204. Additionally, the manufacture 200 includes the nanoparticles 206 substantially uniformly distributed throughout a three dimensional mass of the manufacture 200. A novel result of the method includes the nanoparticles 206 substantially uniformly distributed where three or more interfaces intersect or at triple points 210 of the glass material 201. Preferably, the nanoparticles 206 comprise an average diameter suitable for bonding within the molecular structure 204 of the glass material 201. In an exemplary embodiment, the nanoparticles 206 have an average diameter of approximately 1 to 40 nm. Preferably, the average diameter of the nanoparticles 206 is 20 nm+/−10 nm.

Turning to FIG. 3, a method is shown for making a glass with improved fracture toughness in accordance with an embodiment of the invention. The method step 310 comprises providing a quantity of nanoparticles 206 which are suitable for bonding with glass material. The nanoparticles 206 preferably comprise an average diameter of 5-15 nm+/−4 nm. The nanoparticles 206 can be in the form of a powder. Any suitable method of providing the nanoparticles 206 known to a person of skill can be used. Such methods can include attrition of some kind. For example, ball milling or feeding micron sized material into a plasma process such as described and claimed in the co-owned and co-pending application Ser. No. 11/110,341, filed Apr. 19, 2005, and titled “High Throughput Discovery of Materials Through Vapor Phase Synthesis,” which is incorporated herein by reference. The method step 320 comprises providing a quantity of glass matrix material 201. The matrix material 201 comprises an average grain diameter of 500-600 nm. Alternatively, the matrix material 201 can comprise an average grain diameter of one micrometer. The matrix material 201 typically comprises a powered substance. The matrix material 201 can comprise a form of miniature beads or spheres.

The method step 330 comprises preparing a dispersion 332 of the nanoparticles 206 of the step 310. The dispersion 332 comprises a suspension of the nanoparticles 206 in a suitable liquid or suspension liquid. The nanoparticles 206 can comprise a nano-metal with an average diameter of 5-15 nm+/−4 nm. The nanoparticles 206 can comprise 0.5-20% of the dispersion 332. Alternatively, the nanoparticles 206 can comprise 0.5-10% of the dispersion 332. In another alternative, the nanoparticles 206 can comprise approximately 1.0% of the dispersion 332. In an exemplary embodiment, the suspension liquid comprises water and a surfactant. The surfactant can comprise ten percent of the suspension liquid. Any suitable surfactant can be used. Such surfactants are manufactured by Lubrizol Corporation. In an alternative embodiment, a wetting agent can also be included in the suspension liquid. The wetting agent can be five percent relative to water of the suspension liquid. Alternatively, the suspension liquid comprises an alcohol. Other liquids known to a person of skill can also be utilized. The dispersion 332 comprises a pH suitable for best mixing results with a slurry 342 of the step 340. In an exemplary embodiment, the pH of the dispersion 332 comprises a base. In another embodiment, the base pH comprises a 7.5 pH.

A feature of the method of the invention contemplates that the dispersion 332 comprises a substantially uniform distribution of the nanoparticles 206 within the liquid. The uniform dispersion 332 facilitates a uniform diameter of the nanoparticles 206 in the suspension and prevents a forming of large aggregations of the nanoparticles 206. A high concentration of large aggregations of nanoparticles 206 inhibit the desired uniform distribution of the nanoparticles 206 within the molecular structure 204 of the manufacture 200.

The method step 340 comprises preparing a slurry 342 of the glass matrix material 201 of the step 320. The slurry 342 preferably comprises a viscous suspension of the glass matrix material 201 in a suitable liquid. The glass matrix material 201 can comprise SiO2 with an average diameter of 500-600 nm. The glass matrix material 201 can comprise 50% of the slurry 342. In an exemplary embodiment, the suspension liquid comprises water. Other liquids known to a person of skill can also be utilized. The slurry 342 can include various additives or binders that facilitate a mixing, a drying, a melting and a sintering step described later below. The slurry 342 comprises a pH suitable for best mixing results with the dispersion 332. In an exemplary embodiment, the pH of the slurry 342 comprises a base. In one embodiment, the base pH comprises an 8.0-9.0 pH. In another embodiment, the base pH comprises an 11.0 pH.

The method step 350 comprises mixing the nano-dispersion 332 with the matrix slurry 342 to form a nano-dispersion/slurry mixture 352. The mixing of the nano-dispersion/slurry mixture 352 can comprise suitable agitation methods known to a person of skill. The mixing of the nano-dispersion/slurry mixture 352 produces a dispersion of the nanoparticles 206 within the matrix slurry so that the nanoparticles 206 are uniformly distributed throughout the nano-dispersion/slurry mixture 352. In an exemplary embodiment, the mixing comprises slowly pouring the slurry 342 into the dispersion 332. Preferably, the nano-dispersion/slurry mixture 352 is sonicated during the pouring of the slurry 342. A sonicating horn can be dipped in the dispersion 332 while pouring the slurry 342. A stir bar can optionally be placed in the dispersion 332 during the pouring of the slurry 342. The stir bar can be used to agitate the nano-dispersion/slurry mixture 352 while pouring the slurry 342. The percentage of the nano-dispersion/slurry mixture 352 that comprises the nano-dispersion 332 can vary between 0.5% to 20%. Alternatively, the nano-dispersion/slurry mixture 352 comprises 0.5% to 10% of the nano-dispersion 332. In another alternative, the nano-dispersion/slurry mixture 352 comprises 0.5% to 3.0% of the nano-dispersion 332.

In an alternative embodiment, the mixing comprises slowly pouring the dispersion 332 into the slurry 342. The nano-dispersion/slurry mixture 352 is sonicated during the pouring of the dispersion 332. A sonicating horn can be dipped in the slurry 342 while pouring the dispersion 332. A stir bar can be placed in the slurry 342 during the pouring of the dispersion 332. The stir bar can be used to agitate the nano-dispersion/slurry mixture 352 while pouring the dispersion 332. Other mixing techniques known to a person of skill the art can be substituted for the mixing and agitation described above.

In one embodiment, the various additives or binders that facilitate mixing, drying and sintering can be added to the slurry 342 before the mixing step of step 350. Alternatively, the additives or binders can be added to the nano-dispersion/slurry mixture 352 after the mixing step 350.

The method step 360 comprises drying the nano-dispersion/slurry mixture 352. In an exemplary embodiment, a spray drying process is utilized to dry the nano-dispersion/slurry mixture 352. The spray drying process comprises loading a spray gun and spraying the nano-dispersion/slurry mixture 352 into a closed compartment, for example, a glove box. The nano-dispersion/slurry mixture 352 is sprayed within the compartment and then allowed to dry. As the drying process proceeds, appreciable amounts of the liquid of the nano-dispersion/slurry mixture 352 evaporate to result in a powdered form or a premanufacture 368. In an alternative embodiment, the method step 360 comprises a freeze drying process. Freeze drying comprises placing the nano-dispersion/slurry mixture 352 into a freeze dryer and allowing the liquid of the nano-dispersion/slurry mixture 352 to evaporate until what results comprises the powdered form or the premanufacture 368.

The process step 365 comprises the premanufacture 368 which is the result of the drying step 360. The premanufacture 368 comprises the nanoparticles 206 uniformly distributed throughout the glass matrix material 201.

The method step 370 comprises a process to make the powdered premanufacture 368 a melt. Making the powdered premanufacture 368 a melt comprises placing the powdered premanufacture 368 of the method step 365 into a mold and pressing the powdered premanufacture 368 to form a molded premanufacture 372. Heat is also applied to the molded premanufacture 372 sufficient to liquify and integrate the nanoparticles 206 with the matrix material 201. A person of skill will choose any suitable method of heating the molded premanufacture 372 to cause liquidisation. The molded premanufacture 372 is allowed to cool.

The method step 380 comprises a process of sintering the molded premanufacture 372. The sintering process comprises using any of a variety of sintering processes. In an exemplary embodiment, the sintering process comprises a hot isostatic pressing (HIP) process. The hot isostatic pressing comprises placing the molded premanufacture 372 into a HIP furnace where the molded premanufacture 372 is heated under pressure. The HIP process facilitates a removal of porosity within the molded premanufacture 372. In an alternative embodiment, a liquid phase sintering process as practiced in the art can be used for the method step 380. In yet another embodiment, a simple hot pressing process as practiced in the art can be used.

Referring back to FIG. 2, a result of the method 300 comprises the manufacture 200 with improved fracture toughness in accordance with an embodiment of the invention. The manufacture 200 comprises a composite of a glass material 201 and nanoparticles or nano-material 206. The novel feature of the method 300 produces the manufacture 200 comprising the nanoparticles 206 uniformly distributed throughout the glass material 201.

While the invention has been described with reference to numerous specific details, one of ordinary skill in the art will recognize that the invention can be embodied in other specific forms without departing from the spirit of the invention. Thus, one of ordinary skill in the art will understand that the invention is not to be limited by the foregoing illustrative details, but rather is to be defined by the appended claims.

Claims

1. A method of making glass comprising: providing a plasma created nano-material with an average diameter of 1-15 nanometers;preparing a dispersion of the nano-material;preparing a slurry of a glass matrix material;mixing the nano-dispersion with the matrix slurry to form a nano-dispersion/slurry mixture;drying the nano-dispersion/slurry mixture; andpressing the nano-dispersion/slurry mixture into a final manufacture comprising a molecular structure including the nano-material bonded within and uniformly distributed throughout the molecular structure.

2. The method of claim 1, wherein the mixing comprises pouring the slurry into the dispersion while agitating the nano-dispersion/slurry mixture.

3. The method of claim 1, wherein the mixing comprises pouring the dispersion into the slurry while agitating the nano-dispersion/slurry mixture.

4. The method of claim 1, further comprising providing a micron sized matrix material having an average grain size greater than or equal to 1 micrometer before the slurry preparing step.

5. The method of claim 1, wherein one percent of the nano-dispersion/slurry mixture comprises the nano-material dispersion.

6. The method of claim 1, wherein 0.5-10.0 percent of the nano-dispersion/slurry mixture comprises the nano-material dispersion.

7. The method of claim 1, wherein 0.5-20.0 percent of the nano-dispersion/slurry mixture comprises the nano-material dispersion.

8. The method of claim 1, further comprising sintering the final form using a sintering process following the pressing step.

9. The method of claim 8, wherein the sintering process comprises a hot isostatic pressing process.

10. The method of claim 1, wherein the manufacture includes the nano-material bonded at triple points of the molecular structure.

11. The method of claim 1, wherein the drying of the nano-dispersion/slurry mixture comprises a spray drying process.

12. The method of claim 1, wherein the drying of the nano-dispersion/slurry mixture comprises a freeze drying process.

13. The method of claim 1, wherein the nano-material comprises a non-oxide ceramic material.

14. The method of claim 1, wherein the nano-material comprises an oxide ceramic material that is nonmiscible with the glass matrix material.

15. A method of making glass comprising: providing a plasma created metallic nano-material with an average diameter of 1-15 nanometers;preparing a dispersion of the metallic nano-material;preparing a slurry of a glass matrix material;mixing the nano-dispersion with the matrix slurry to form a nano-dispersion/slurry mixture;drying the nano-dispersion/slurry mixture; andpressing the nano-dispersion/slurry mixture into a final manufacture comprising a molecular structure including the nano-material bonded within and uniformly distributed throughout the molecular structure.

16. The method of claim 15, wherein the mixing comprises pouring the slurry into the dispersion while agitating the nano-dispersion/slurry mixture.

17. The method of claim 15, wherein the mixing comprises pouring the dispersion into the slurry while agitating the nano-dispersion/slurry mixture.

18. The method of claim 15, further comprising providing a micron sized matrix material having an average grain size greater than or equal to 1 micrometer before the slurry preparing step.

19. The method of claim 15, wherein one percent of the nano-dispersion/slurry mixture comprises the nano-material dispersion.

20. The method of claim 15, wherein 0.5-10.0 percent of the nano-dispersion/slurry mixture comprises the nano-material dispersion.

21. The method of claim 15, wherein 0.5-20.0 percent of the nano-dispersion/slurry mixture comprises the nano-material dispersion.

22. The method of claim 15, further comprising sintering the final form using a sintering process following the pressing step.

23. The method of claim 22, wherein the sintering process comprises a hot isostatic pressing process.

24. The method of claim 15, wherein the manufacture includes the nano-material bonded at triple points of the molecular structure.

25. The method of claim 15, wherein the drying of the nano-dispersion/slurry mixture comprises a spray drying process.

26. The method of claim 15, wherein the drying of the nano-dispersion/slurry mixture comprises a freeze drying process.