Vanadium-based frit materials, and/or methods of making the same

Abstract

Certain example embodiments relate to improved seals for glass articles. Certain example embodiments relate to a composition used for sealing an insulted glass unit. In certain example embodiments the composition includes vanadium oxide, barium oxide, zinc oxide, and at least one additional additive. For instance, another additive that is a different metal oxide or different metal chloride may be provided. In certain example embodiments, a vacuum insulated glass unit includes first and second glass substrates that are sealed together with a seal that includes the above-described composition.

Description

FIELD OF THE INVENTION

Certain example embodiments of this invention relate to improved frit materials for glass articles (e.g., for use in vacuum insulated glass or VIG units), and/or methods of making the same, as well as articles including such improved frit materials and/or methods of making the same. More particularly, certain example embodiments relate to vanadium-based frit materials having a reduced melting point, and/or methods of making the same. In certain example embodiments, the improved insulated seals are used in connection with vacuum insulated glass (VIG) units, and/or a method is provided for sealing VIG units with the improved seals.

BACKGROUND AND SUMMARY OF EXAMPLE EMBODIMENTS OF THE INVENTION

Vacuum IG units are known in the art. For example, see U.S. Pat. Nos. 5,664,395, 5,657,607, and 5,902,652, the disclosures of which are all hereby incorporated herein by reference.

FIGS. 1-2 illustrate a conventional vacuum IG unit (vacuum IG unit or VIG unit). Vacuum IG unit 1 includes two spaced apart glass substrates 2 and 3, which enclose an evacuated or low pressure space 6 there between. Glass sheets/substrates 2 and 3 are interconnected by peripheral or edge seal of fused solder glass 4 and an array of support pillars or spacers 5.

Pump out tube 8 is hermetically sealed by solder glass 9 to an aperture or hole 10 which passes from an interior surface of glass sheet 2 to the bottom of recess 11 in the exterior face of sheet 2. A vacuum is attached to pump out tube 8 so that the interior cavity between substrates 2 and 3 can be evacuated to create a low pressure area or space 6. After evacuation, tube 8 is melted to seal the vacuum. Recess 11 retains sealed tube 8. Optionally, a chemical getter 12 may be included within recess 13.

Conventional vacuum IG units, with their fused solder glass peripheral seals 4, have been manufactured as follows. Glass frit in a solution (ultimately to form solder glass edge seal 4) is initially deposited around the periphery of substrate 2. The other substrate 3 is brought down over top of substrate 2 so as to sandwich spacers 5 and the glass frit/solution there between. The entire assembly including sheets 2, 3, the spacers, and the seal material is then heated to a temperature of approximately 500° C., at which point the glass frit melts, wets the surfaces of the glass sheets 2, 3, and ultimately forms hermetic peripheral or edge seal 4. This approximately 500° C. temperature is maintained for from about one to eight hours. After formation of the peripheral/edge seal 4 and the seal around tube 8, the assembly is cooled to room temperature. It is noted that column 2 of U.S. Pat. No. 5,664,395 states that a conventional vacuum IG processing temperature is approximately 500° C. for one hour. Inventors Lenzen, Turner and Collins of the '395 patent have stated that “the edge seal process is currently quite slow: typically the temperature of the sample is increased at 200° C. per hour, and held for one hour at a constant value ranging from 430° C. and 530° C. depending on the solder glass composition.” After formation of edge seal 4, a vacuum is drawn via the tube to form low pressure space 6.

The composition of conventional edge seals are known in the art. See, for example, U.S. Pat. Nos. 3,837,866; 4,256,495; 4,743,302; 5,051,381; 5,188,990; 5,336,644; 5,534,469; 7,425,518, and U.S. Publication No. 2005/0233885, the disclosures of which are all hereby incorporated herein by reference.

Unfortunately, the aforesaid high temperatures and long heating times of the entire assembly utilized in the formulation of edge seal 4 are undesirable. This is especially the case when it is desired to use a heat strengthened or tempered glass substrate(s) 2, 3 in the vacuum IG unit. As shown in FIGS. 3-4, tempered glass loses temper strength upon exposure to high temperatures as a function of heating time. Moreover, such high processing temperatures may adversely affect certain low-E coating(s) that may be applied to one or both of the glass substrates in certain instances.

FIG. 3 is a graph illustrating how fully thermally tempered plate glass loses original temper upon exposure to different temperatures for different periods of time, where the original center tension stress is 3,200 MU per inch. The x-axis in FIG. 3 is exponentially representative of time in hours (from 1 to 1,000 hours), while the y-axis is indicative of the percentage of original temper strength remaining after heat exposure. FIG. 4 is a graph similar to FIG. 3, except that the x-axis in FIG. 4 extends from zero to one hour exponentially.

Seven different curves are illustrated in FIG. 3, each indicative of a different temperature exposure in degrees Fahrenheit (° F.). The different curves/lines are 400° F. (across the top of the FIG. 3 graph), 500° F., 600° F., 700° F., 800° F., 900° F., and 950° F. (the bottom curve of the FIG. 3 graph). A temperature of 900° F. is equivalent to approximately 482° C., which is within the range utilized for forming the aforesaid conventional solder glass peripheral seal 4 in FIGS. 1-2. Thus, attention is drawn to the 900° F. curve in FIG. 3, labeled by reference number 18. As shown, only 20% of the original temper strength remains after one hour at this temperature (900° F. or 482° C.). Such a significant loss (i.e., 80% loss) of temper strength may be undesirable.

As seen in FIGS. 3-4, the percentage of remaining tempering strength varies based on the temperature that is exposed to, the tempered glass. For example, at 900° F. only about 20% of the original temper strength remains. When the temperature that the sheet is exposed to is reduced to 800° F., about 428° C., the amount of strength remaining is about 70%. Finally, a reduction in temperature to about 600° F., about 315° C., results in about 95% of the original temper strength of the sheet remaining. As will be appreciated, it is desirable to reduce any temper strength losses as a result of exposing a tempered sheet of glass to high temperatures.

As noted above, the creation of VIG units includes the creation of a hermetic seal that can withstand the pressure applied from the vacuum created on inside of the unit. As also discussed above, the creation of the seal may conventionally involve temperatures of at or above 500° C. These temperatures are required in order to obtain a high enough temperature in order for the frit material used for the seal to melt and form the required seal for the VIG units. As shown above, such a temperature can result in a strength reduction for VIG units using tempered glass.

One conventional solution to sealing glass substrates together is to use an epoxy. However, in the case of VIG units, epoxy compositions may be insufficient to hold a seal on a vacuum. Furthermore, epoxies may be susceptible to environmental factors that may further reduce their effectiveness when applied to VIG units.

Another conventional solution is to use a frit solution that contains lead. As is known, lead has a relatively low melting point. Accordingly, temperatures for sealing the VIG units may not need to be as high for other frit materials, and thus the tempering strength of tempered glass substrates may not be reduced by the same amount required for other frit based materials. However, while lead based frits may resolve the above structural issues, the usage of lead in the fit may create new problems. Specifically, the health consequences to the population for products that contain lead. Additionally, certain countries (e.g., in the European Union) may impose strict requirements on the amount of lead that can be contained in a given product. Indeed, some countries (or customers) may require products that are completely lead-free.

Thus, it will be appreciated that techniques for creating improved seals for glass articles are continuously sought after. It also will be appreciated that there exists a need in the art for improved seals and the like that can be integrated with tempered glass units, such as, for example, VIG units. The seals may be designed to allow for reduced temperature sealing such that annealed or tempered glass can be sealed without detrimental impact on the properties of the glass.

In certain example embodiments, a frit material may provide glass to frit bonding sufficient for VIG purposes (e.g., in terms of structural strength). In certain example embodiments, the provided frit may provide proper glass wetting properties. In certain example embodiments, the frit may seal and have structural strength and a homogenous glassy structure to provide an adequate barrier to prevent vacuum degradation in example VIG units over a period of time.

In certain instances, improvements in melt flow may enable improved fit matching to glass expansion and/or increase process tolerances to frit bead variations. Improved wetting and bonding properties of a frit material may increase VIG yield by reducing bonding failures of the frit to the glass. A reduction in crystallization may additionally or alternatively facilitate a selected composition to meeting different heating environments (e.g., an internal seal, an external seal, etc).

In certain example embodiments, a frit material having a composition is provided. The frit material may include vanadium oxide between about 50% and 60% weight, barium oxide between about 27% and 33% weight, and zinc oxide between about 9% and 12% weight. In certain example embodiments, the frit material may also include at least one additive selected from among: Ta₂O₅, Ti₂O₃, SrCl₂, GeO₂, CuO, AgO, Nb₂O₅, B₂O₃, MgO, SiO₂, TeO₂, Tl₂O₃, Y₂O₃, SnF2, SnO2, CuCl, SnCl₂, CeO₂, AgCl, In₂O₃, SnO, SrO, MgO, MoO₃, CsCO₃, CuCl₂, and Al₂O₃.

In certain example embodiments, a vacuum insulted glass (VIG) unit is provided. The VIG unit may include first and second substantially parallel, spaced apart glass substrates. An edge seal is provided around a periphery of the first and second substrates to form a hermetic seal there between and at least partially defining a gap between the first and second substrates. The gap defined between the first and second substrates is at a pressure less than atmospheric. The edge seal includes a frit material, e.g., as made from a base composition as described herein.

In certain example embodiments, a method of making a frit material is provided. A base composition is provided to a holder. The base composition includes vanadium oxide between about 50% and 60% weight, barium oxide between about 27% and 33% weight, zinc oxide between about 9% and 12% weight, and at least one additive selected from among: Ta₂O₅, Ti₂O₃, SrCl₂, GeO₂, CuO, AgO, Nb₂O₅, B₂O₃, MgO, SiO₂, TeO2, Tl2O3, Y2O3, SnF2, SnO2, CuCl, SnCl2, CeO2, AgCl, In2O3, SnO, SrO, MgO, MoO₃, CsCO₃, CuCl₂, and Al₂O₃. The base composition is melted. The base composition is cooled or allowed to cool, forming an intermediate glass article. The intermediate glass article is ground to make the frit material.

In certain example embodiments, a method of making a vacuum insulated glass (VIG) unit is provided. First and second glass substrates in substantially parallel, spaced apart relation to one another are provided. The first and second glass substrates using a frit material are sealed together, with a gap being defined between the first and second substrates. The sealing being performed by melting the frit material at a temperature of no more than about 400 degrees C. Where the frit material has been formed from a base composition including vanadium oxide between about 50% and 60% weight, barium oxide between about 27% and 33% weight, zinc oxide between about 9% and 12% weight, and at least one oxide or chloride-base additive.

In certain example embodiments, a frit material having a composition is provided. The frit material may include vanadium oxide between about 50% and 60% weight (40-55% molar, more preferably 45-50% molar), barium oxide (e.g., barium carbonate that converts in whole or in part to BaO) between about 23% and 33% weight (15-35% molar, more preferably 20-23% molar), and zinc oxide between about 9% and 12% weight (15-25% molar, more preferably 19-22% molar). The frit material includes at least a first and second additive selected from among SnCl₂, CuCl₂, MoO₃, TeO₂, Ta₂O₅, Nb₂O₅, Al₂O₃, SiO₂, and CsCO₃.

Certain example embodiments may include at least two additives. For example SnCl2 and SiO2. Certain example embodiments may include three or four additives selected from among SiO₂, SnCl₂, Al₂O₃, and TeO₂. Certain example embodiments may use between 5 and 10 different additives that are selected from among: SnCl₂, CuCl₂, MoO₃, TeO₂, Ta₂O₅, Nb₂O₅, Al₂O₃, SiO₃, and CsCO₃.

The features, aspects, advantages, and example embodiments described herein may be combined in any suitable combination or sub-combination to realize yet further embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features and advantages may be better and more completely understood by reference to the following detailed description of exemplary illustrative embodiments in conjunction with the drawings, of which:

FIG. 1 is a cross-sectional view of a conventional vacuum IG unit;

FIG. 2 is a top plan view of the bottom substrate, edge seal, and spacers of the FIG. 1 vacuum IG unit taken along the section line illustrated in FIG. 1;

FIG. 3 is a graph correlating time (hours) versus percent tempering strength remaining, illustrating the loss of original temper strength for a thermally tempered sheet of glass after exposure to different temperatures for different periods of time;

FIG. 4 is a graph correlating time versus percent tempering strength remaining similar to that of FIG. 3, except that a smaller time period is provided on the x-axis;

FIG. 5 is cross-sectional view of a vacuum insulated glass unit according to certain example embodiments;

FIG. 6 is a flowchart illustrating a process for making a vacuum insulated glass unit with a frit material according to certain example embodiments;

FIGS. 7A-7D are graphs summarizing properties of compositions according to certain example embodiments;

FIGS. 8A-8C are graphs summarizing the quality of compositions according to certain exemplary embodiments;

FIG. 9 is a graph showing results when additional elements are added to compositions according to certain example embodiments;

FIGS. 10A-10C show graphs summarizing impacts of additives being added to vanadium based frits according to certain example embodiments;

FIGS. 11A-11C show graphs summarizing absorption in the visible and infrared wavelengths for vanadium based frits according to certain example embodiments; and

FIGS. 12A-12C are graphs summarizing flow characteristics of example frit materials according to certain example embodiments.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS OF THE INVENTION

The following description is provided in relation to several example embodiments which may share common characteristics, features, etc. It is to be understood that one or more features of any one embodiment may be combinable with one or more features of other embodiments. In addition, single features or a combination of features may constitute an additional embodiment(s).

Certain example embodiments may relate to glass units (e.g., VIG units) that include two glass substrates sealed with an improved seal, e.g., of or including a vanadium-based frit material. In certain example embodiments an improved seal may include the following materials: vanadium oxide, barium oxide, and zinc oxide. In addition, certain example embodiments may include one or more of the following compounds: Ta₂O₅, Ti₂O₃, SrCl₂, GeO₂, CuO, AgO, Nb₂O₅, B₂O₃, MgO, SiO₂, TeO2, Tl2O3, Y2O3, SnF2, SnO2, CuCl, SnCl2, CeO2, AgCl, In2O3, SnO, SrO, MgO, MoO₃, CsCO₃, CuCl₂, and Al₂O₃.

FIG. 5 is cross-sectional view of a vacuum insulated glass unit according to certain example embodiments. VIG unit 500 may include first and second glass substrates 502a and 502b that are spaced apart and define a space therebetween. The glass substrates 502a and 502b may be connected via an improved seal 504, of or including a vanadium-based frit. Support pillars 506 may help maintain the first and second substrates 502a and 502b in substantially parallel spaced apart relation to one another. It will be appreciated that the CTE of the improved seal 504 and the glass substrates 502a and 502b may substantially match one another. This may be advantageous in terms of reducing the likelihood of the glass cracking, etc. Although FIG. 5 is described in relation to a VIG unit, it will be appreciated that the improved seal 504, of or including a vanadium-based frit may be used in connection with other articles and/or arrangements including, for example, insulating glass (IG) units and/or other articles.

FIG. 6 is a flowchart illustrating a process for preparing a frit material to be used in making a vacuum insulated glass unit according to certain example embodiments. In step 600, base compounds are combined and disposed into an appropriate container (e.g., a heat resistant container such as, for example, a ceramic container). In step 602, the combined compound is melted. Preferably, the temperature to melt the combined material may be at least 1000° C. In certain exemplary embodiments, the combined compound is melted at 1000° C. for between 30 to 60 minutes. In certain exemplary embodiments, the combined compound is melted at 1100° C. for 60 minutes. In certain exemplary embodiments, the combined compound is melted at 1200° C. for 60 minutes. In certain exemplary embodiments, the melting temperature is a cycle that includes 500° C. for 15 minutes, 550° C. for 15 minutes, 600° C. for 15 minutes, and a ramp up to 1000° C. for 60 minutes.

After the combined compounds are melted, the material may be cooled in step 604, e.g., to form a glass sheet. After cooling, the glass may be crushed or ground into fine particulates in step 606. In certain example embodiments, the size of the particulates may be no larger than about 100 mesh. Once the glass is ground into a powder, it may be disposed between the substrates in step 608. In certain example embodiments, the powder may be dispensed as a paste with a binder. Heat may then be applied in step 610 to the glass substrate and the powder. In certain example embodiments, the heat may be between 300° C. and 400° C., or more preferably between 325° C. and 375° C. It will be appreciated that when heat of the above temperatures is applied to tempered glass that the tempered glass may lose a reduced amount of strength versus when heat of in excess of 350° C. is applied to the tempered glass. Thus, certain example embodiments preferably involve a frit melting temperature of less than 500° C., more preferably less than 425° C., and sometimes less than 350° C.

In certain example embodiments, the combined compounds include the following materials: vanadium oxide, barium oxide, and zinc oxide.

FIGS. 7A-7D show graphs summarizing properties of compositions according to certain example embodiments.

The table below corresponds to the data shown in FIG. 7A with those compositions with a melt quality of less than 4 (on a scale of 0 to 5) omitted from the table.

TABLE 1
Normalized Moles of Batch Composition
V2O5	BaO	ZnO	BaO/ZnO	Bi2O3	B2O3	Tg (C.)	Tx1 (C.)	Rating
43.66%	9.87%	46.47%	0.21			320	410	4
39.01%	13.25%	37.37%	.35	2.18%	8.20%	312	430	4
47.33%	12.96%	24.41%	0.53	9.95%	5.53%	305	380	4
50.24%	23.38%	21.39%	1.33			320	425	4
51.54%	26.26%	16.46%	1.60	5.75%		320	410	4.5

The melts shown in FIG. 7A were applied to a microscope glass slide with a temperature of 375° C. applied for 15 minutes. FIG. 7B shows a graph that includes the crystallization temperature (first crystallization peak—Tx1—of the above table) of the above melts. According to certain exemplary embodiments, a preferred temperature for Tx1 may be between about 375° C. and 425° C., preferably about 400° C.

FIG. 7C shows the transition glass temperatures, Tg, compared the above melts. The graph showing exemplary data shows that Tg values between about 290 C and 335 C may be preferred for the above compositions.

FIG. 7D includes the above melts in a graph showing the melt quality versus the barium/zinc ratio.

FIGS. 8A-8C show graphs that summarize the quality of compositions according to certain exemplary embodiments. FIG. 8A summarizes the V₂O₅ percentage used in certain exemplary compositions. FIG. 8B summarizes the BaO percentage used in certain exemplary compositions. FIG. 8C summarizes the ZnO percentage used in certain exemplary compositions. As shown in the illustrative graphs, a vanadium percentage of between about 51% and 53% may be preferable according to certain example embodiments.

Below, tables 2A-2C show exemplary compositions according to certain example embodiments. Additionally, examples 7-15 in the tables correspond to graphs 8A-8C. For the compositions shown in the below tables, BaCO₃ factor of 1.287027979 was used to convert to a BaO resulting compound.

	TABLE 2A
			Weights of Batch
	Weight		Composition	Normalized Weight
	Percentage		for 25 grams	Percentage
Ex.	V2O5	BaO	ZnO	Weight Normal	V2O5	BaO	ZnO	V2O5	BaO	ZnO
1	60	30	10	0.23	13.800	8.880	2.300	55.24	35.55	9.21
2	52.5	25	10	0.27	14.175	8.687	2.700	55.45	33.99	10.56
3	45	20	10	0.31	13.950	7.980	3.100	55.73	31.88	12.39
4	45	10	20	0.32	14.400	4.118	6.400	57.79	16.53	25.68
5	52.5	10	25	0.28	14.700	3.604	7.000	58.09	14.24	27.66
6	60	10	30	0.25	15.000	3.218	7.500	58.33	12.51	29.16
7	52.5	25	10	0.24	12.600	7.722	2.400	55.45	33.99	10.56
8	57.5	25	10	0.25	14.375	8.044	2.500	57.69	32.28	10.03
9	47.5	25	10	0.28	13.300	9.009	2.800	52.97	35.88	11.15
10	52.5	27.5	10	0.26	13.650	9.202	2.600	53.63	36.15	10.22
11	57.5	27.5	10	0.25	14.375	8.848	2.500	55.88	34.40	9.72
12	47.5	27.5	10	0.27	12.825	9.556	2.700	51.13	38.10	10.77
13	52.5	22.5	10	0.28	14.700	8.108	2.800	57.40	31.66	10.93
14	57.5	22.5	10	0.26	14.950	7.529	2.600	59.61	30.02	10.37
15	47.5	22.5	10	0.29	13.775	8.398	2.900	54.94	33.49	11.57

	TABLE 2B
	Moles of Batch	Normalized Moles	Glass
Ex.	V2O5	BaO	ZnO	V2O5	BaO	ZnO	Type
1	0.3037	0.1801	0.1132	50.87%	30.17%	18.95%	amor-
							phous
2	0.3049	0.1722	0.1298	50.24%	28.38%	21.39%	glassy
3	0.3064	0.1616	0.1522	49.41%	26.05%	24.54%	amor-
							phous
4	0.3177	0.0838	0.3156	44.31%	11.68%	44.01%	amor-
							phous
5	0.3194	0.0722	0.3400	43.66%	9.87%	46.47%	amor-
							phous
6	0.3207	0.0634	0.3584	43.19%	8.54%	48.27%	amor-
							phous
7	0.3049	0.1722	0.1298	50.24%	28.38%	21.39%	glassy
8	0.3172	0.1636	0.1233	52.51%	27.08%	20.41%	glassy
9	0.2912	0.1818	0.1370	47.74%	29.80%	22.46%	glassy
10	0.2949	0.1832	0.1255	48.85%	30.35%	20.80%	glassy
11	0.3073	0.1743	0.1194	51.12%	29.00%	19.87%	glassy
12	0.2811	0.1931	0.1323	46.35%	31.83%	21.81%	glassy
13	0.3156	0.1604	0.1344	51.70%	26.28%	22.01%	glassy
14	0.3278	0.1521	0.1274	53.97%	25.05%	20.98%	glassy
15	0.3021	0.1697	0.1421	49.20%	27.65%	23.15%	glassy

The rating shown in Table 2C is based off of deposing the ground composition on a microscope glass slide and heating the composition at about 375° C. for between 10 and 30 minutes.

TABLE 2C
Example	Tg (C. °)	Tx2 (C. °)	Tx2 (C. °)	Tx1 − Tg	Rating
1	280	330	540	50	0.0
2	320	425	525	105	4.0
3	280	430	550	150	0.0
4	280	320	365	40	0.0
5	320	410	560	90	4.0
6	285	425	560	140	0.0
7	315	390	530	75	4.5
8	295, 325	415	535	90	5.0
9	320	420	525	100	4.5
10	325	410	540	85	4.5
11	315	395	530	80	4.5
12	330	415	560	85	4.0
13	315	400	530	85	5.0
14	305	395	530	90	4.0
15	320	395	525	75	4.5

FIG. 9 shows a graph with results of adding additional elements (e.g., Bi₂O₃ and B₂O₃) to a vanadium based frit. Corresponding data shown in FIG. 9 is also displayed below in Table 3.

TABLE 3
Ex.	V2O5	BaO	ZnO	Bi2O3	B2O3	Tg (C.)	Tx1 (C.)	DSC Responses
1	65.39%	14.87%	12.46%	0.00%	7.28%	320	430	medium weak
2	60.96%	13.86%	11.61%	0.00%	13.57%	240	415	very weak
3	69.71%	15.85%	13.28%	1.16%	0.00%	315	405	strong peaks
4	64.69%	14.71%	12.32%	1.08%	7.20%	325	440	very weak
5	68.91%	15.67%	13.13%	2.29%	0.00%	320	410	medium weak
6	64.00%	14.56%	12.19%	2.13%	7.12%	320	425	very weak
7	59.74%	13.59%	11.38%	1.99%	13.30%	315	410	very weak
8	60.34%	13.72%	11.49%	1.00%	13.43%	315	400	very weak
9	70.53%	16.04%	13.43%	0.00%	0.00%	315	380	strong peaks

In certain example embodiments, a strong DSC response may correspond to a good remelt quality. In certain example embodiments, the addition of bismuth in concentrations of between about 0% and 3% may result in increased remelt flow quality.

In certain example embodiments, a frit that includes V₂O₅, BaO, and ZnO may further include one or more additives. In certain example embodiments, the additives may be between about 0.5% and 15% weight. According to certain example embodiments, the additives may be added to a base composition that includes between about 50% and 60% weight V₂O₅, 27% and 33% weight BaO, and 9% and 12% weight ZnO.

Below, Tables 4A-4D show results of including additives to the base composition of V₂O₅, BaO, and ZnO. Table 4D shows the melt quality on a scale of about 0 to 5 for each of the compositions. FIGS. 10A-10C show graphs corresponding to the data shown in the below tables. A BaCO3 factor of 1.2870 was used to form the BaO used for the following examples.

	TABLE 4A
	Weights (gm)	Normalized Weights
Ex	V2O5	BaO	ZnO	Additive Type	Amount	V2O5	BaO	ZnO	Additive
1	52.5	22.5	10	TeO2	2	14.175	7.819	2.700	0.540
2	52.5	22.5	10	TeO2	4	13.650	7.529	2.600	1.040
3	52.5	22.5	10	Ta2O5	5	13.650	7.529	2.600	1.300
4	52.5	22.5	10	Ta2O5	10	13.125	7.240	2.500	2.500
5	52.5	22.5	10	Ti2O3	5	13.650	7.529	2.600	1.300
6	52.5	22.5	10	Ti2O3	10	13.125	7.240	2.500	2.500
7	52.5	22.5	10	SrCl2	2	14.175	7.819	2.700	0.540
8	52.5	22.5	10	SrCl2	4	13.650	7.529	2.600	1.040
9	52.5	22.5	10	GeO2	1	14.175	7.819	2.700	0.270
10	52.5	22.5	10	GeO2	2	14.175	7.819	2.700	0.540
11	52.5	22.5	10	CuO	1	14.175	7.819	2.700	0.270
12	52.5	22.5	10	CuO	2	14.175	7.819	2.700	0.540
13	52.5	22.5	10	AgO	1.5	14.175	7.819	2.700	0.405
14	52.5	22.5	10	AgO	3	14.175	7.819	2.700	0.810
15	52.5	22.5	10	Nb2O5	3	14.175	7.819	2.700	0.810
16	52.5	22.5	10	Nb2O5	6	13.650	7.529	2.600	1.560
17	52.5	22.5	10	B2O3	.8	14.175	7.819	2.700	0.216
18	52.5	22.5	10	B2O3	1.6	14.175	7.819	2.700	0.432

	TABLE 4B
	Moles of Batch Composition
	Normalized Weight Percentage		Addi-
Ex	V2O5	BaO	ZnO	Additive	V2O5	BaO	ZnO	tive
1	56.17	30.99	10.70	2.14	0.309	0.157	0.131	0.013
2	55.00	30.34	10.48	4.19	0.302	0.154	0.129	0.026
3	54.43	30.02	10.37	5.18	0.299	0.152	0.127	0.012
4	51.75	28.54	9.86	9.86	0.285	0.145	0.121	0.022
5	54.43	30.02	10.37	5.18	0.299	0.152	0.127	0.011
6	51.75	28.54	9.86	9.86	0.285	0.145	0.121	0.022
7	56.17	30.99	10.70	2.14	0.309	0.157	0.131	0.013
8	55.00	30.34	10.48	4.19	0.302	0.154	0.129	0.026
9	56.78	31.32	10.82	1.08	0.312	0.159	0.133	0.010
10	56.17	30.99	10.70	2.14	0.309	0.157	0.131	0.020
11	56.78	31.32	10.82	1.08	0.312	0.159	0.133	0.014
12	56.17	30.99	10.70	2.14	0.309	0.157	0.131	0.027
13	56.48	31.15	10.76	1.61	0.311	0.158	0.132	0.013
14	55.58	30.66	10.59	3.18	0.306	0.155	0.130	0.026
15	55.58	30.66	10.59	3.18	0.306	0.155	0.130	0.012
16	53.87	29.71	10.26	6.16	0.296	0.151	0.126	0.023
17	56.91	31.39	10.84	0.87	0.313	0.159	0.133	0.012
18	56.42	31.12	10.75	1.72	0.310	0.158	0.132	0.025

	TABLE 4C
	Normalized Moles
				Addi-	Tg	(Tx1	Tx2	Tx1 −
Ex	V2O5	BaO	ZnO	tive	(C.)	(C.)	(C.)	Tg
1	50.57%	25.71%	21.53%	2.20%	315	400	525	85
2	49.48%	25.16%	21.07%	4.30%	315	420	530	105
3	50.68%	25.76%	21.58%	1.99%	320	450		130
4	49.69%	25.26%	21.16%	3.90%	320	450	530	130
5	50.71%	25.78%	21.59%	1.92%	305	390	495	85
6	49.75%	25.29%	21.18%	3.77%	295	390	470	95
7	50.56%	25.70%	21.53%	2.21%	315	405	530	90
8	49.47%	25.15%	21.06%	4.32%	315	400	530	85
9	50.83%	25.84%	21.64%	1.68%	315	395	530	80
10	49.99%	25.41%	21.28%	3.31%	315	400	530	85
11	50.56%	25.71%	21.53%	2.20%	315	385	525	70
12	49.47%	25.15%	21.06%	4.31%	320	395	545	75
13	50.61%	25.73%	21.55%	2.12%	305	390	525	85
14	49.55%	25.19%	21.10%	4.16%	300	380		80
15	50.68%	25.76%	21.58%	1.98%	315	425	550	110
16	49.69%	25.26%	21.16%	3.89%	325	440	465	115
17	50.66%	25.75%	21.57%	2.02%	315	410	540	95
18	49.66%	25.25%	21.14%	3.95%	320	405	545	85

TABLE 4D
	Melt Quality @	Melt Quality at
Example	375 C., 15 min	350 C., 15 min
1	5.0	4.0
2	4.5	4.0
3	4.5	2.0
4	5.0	2.0
5	4.5	4.5
6	5.0	5.0
7	5.5+	5.0
8	5.0	4.5
9	4.5	4.5
10	4.5	4.5
11	4.5	2.0
12	4.0	2.0
13	4.0	5.0
14	3.5	4.0
15	4.5	2.0
16	5.0	2.0
17	4.0	4.5
18	3.5	2.0

In certain example embodiments, the molar composition of an additive to a base composition higher than is shown in tables 4A-4D. Table 5A shows additives with an increased additive amount (on a % mole basis). The base composition used with the additive amount may be based on, for example, the base composition shown in Row 1 of Tables 4A-4D. The additives shown in Table 5, in the selected quantities displayed, may improve melt quality when compared to the above base composition. A melt type of Glassy indicates that a “button” of the compound melted onto a glass plate, forming a homogenous glassy structure. Sinter indicates that the compound (in a powder form) fused together, but remained in a powder form.

TABLE 5
			Melt Type	Adhesion
	Additive		(350 C. for	to glass
Example	Type	Amount	20 minutes)	substrate.
1	CuCl	4.00%	Glassy	No Stick
2	SnCl2	3.99%	Glassy	No Stick
3	SnCl2	5.99%	Glassy, Slight Flow	Slight stick
4	SiO2	6.02%	More Glassy	No Stick
5	Al2O3	6.00%	Glassy	No Stick
6	CeO2	4.00%	Sinter	No Stick
7	TeO2	3.99%	Glassy	Slight stick
8	TeO2	6.01%	Glassy	Slight stick
9	Tl2O3	3.99%	Glassy, Slight Flow	No Stick
10	Tl2O3	6.01%	Glassy, Slight Flow	No Stick

Accordingly, in certain example embodiments, additives of a relatively increased amount (e.g., versus those shown in FIG. 4) may be added to a base composition. In certain example embodiments, the additives may include, for example, CuCl, SnCl, SnCl₂, SiO₂, Al₂O₃, and TeO₂. It will be appreciated that toxic nature of thallium oxide (Tl₂O₃) may preclude its use in certain instances.

In certain example embodiments, two or more additives may be included in a base compound. Table 6 shows the results of adding two additives to an exemplary base composition. Table 6 includes example melts at 375 and 350. Additionally, 13 mm buttons of the exemplary compounds were tested on a glass plate. The structural strength of the resulting exemplary compound are also shown in the far right column.

TABLE 6
					Melt	Melt	13 mm
					Quality	Quality	Button
			Amount 1	Amount 2	(375 C.	(350 C.	350 C.
Ex	Add 1	Add 2	(Mole %)	(Mole %)	15-20 Min)	15-20 Min)	20 Min	Strength
1	TeO2	Al2O3	3.01	3.01	4.5	5.5	glassy	Fractures
2	TeO2	Al2O3	2.99	5.01	5	4	glassy	Fractures
3	TeO2	Al2O3	4.02	3.01	6	5.5	glassy	Fractures
4	TeO2	Al2O3	3.99	5.00	5	4.5	glassy	Fractures
5	TeO2	Al2O3	5.01	2.99	4.5	4.5	glassy	Fractures
6	TeO2	Al2O3	5.00	5.00	5	4.5	glassy	Fractures
7	TeO2	SiO2	3.01	3.00	5	5.5	glassy	Fractures
8	TeO2	SiO2	2.99	5.02	5	4.5	glassy	Fractures
9	TeO2	SiO2	4.00	2.99	5	4	glassy	Fractures
10	TeO2	SiO2	3.99	4.99	5	4.5	Less	Fractures
							glassy
11	TeO2	SiO2	5.00	2.99	4.5	4.5	Less	Hard
							glassy
12	TeO2	SiO2	5.00	4.99	4.5	4.5	Less	Hard
							glassy
13	SnCl2	Al2O3	3.01	3.01	5	6	more	Hard
							glassy
14	SnCl2	Al2O3	3.00	5.01	5	5.5	glassy	Hard
15	SnCl2	Al2O3	4.01	3.01	4.5	6	glassy	Hard
16	SnCl2	Al2O3	4.00	4.99	5.5	6	glassy	Hard
17	SnCl2	Al2O3	5.00	2.99	5.5	5.5	glassy	Fractures
18	SnCl2	Al2O3	5.00	5.00	5.5	5.5	more	Hard
							glassy
19	SnCl2	SiO2	3.00	3.00	4.5	4.5	glassy	Hard
20	SnCl2	SiO2	3.00	4.99	5	6	glassy	Hard
21	SnCl2	SiO2	4.00	2.99	6	6	glassy	Fractures
22	SnCl2	SiO2	4.01	4.99	5.5	5.5	glassy	Fractures
23	SnCl2	SiO2	5.00	2.99	5	5.5	glassy	Hard
24	SnCl2	SiO2	5.00	4.99	5.5	5.5	glassy	Fractures
25	Al2O3	SiO2	3.01	3.00	4.5	4	less	Hard
							glassy
26	Al2O3	SiO2	2.99	4.99	5	5.5	less	Hard
							glassy
27	Al2O3	SiO2	4.00	2.99	4.5	4.5	less	Hard
							glassy
28	Al2O3	SiO2	4.00	4.99	5	4.5	less	Hard
							glassy
29	Al2O3	SiO2	5.01	2.99	5	4.5	less	Hard
							glassy
30	Al2O3	SiO2	5.01	4.99	4	2	less	Hard
							glassy

Accordingly, certain example may include two additives similar to those found in examples 3, 16, and 21 as shown in Table 6 (e.g., TeO2 with SiO2, SnCl2 with Al2O3, and SnCl2 with SiO2). In certain example embodiments, the addition of two or more additives may have beneficial results on an exemplary base composition. For example the addition of SiO2 to another additive may increase the strength of the overall frit. Alternatively, or in addition, TeO2 combined with other additives may increase the melt flow and glass wetting qualities of the frit when compared to a base frit.

In certain example embodiments, the combination of SnCl2 with SiO2 and/or Al2O3 may result in an increase in structural strength for the resulting frit material.

In certain example embodiments, one or more additives may be added to a base composition where the amount is between 1% and 10% by weight or between about 1% and 6% normalized moles for a batch. In certain example embodiments, additives may be added in a smaller amount, for example between about 0.1% and 1% by weight. In certain example embodiments a batch for a base composition (in grams) may include V₂O₅ at 52.5, BaO at 22.5, ZnO at 10. In certain example embodiments, additives added to the above base composition may include: 1) TeO2 at 3.85 gm and Al2O3 at 1.84 gm; 2) SnCl2 at 4.65 gm and Al2O3 at 3.12 gm; 3) SnCl2 at 4.55 gm and SiO2 at 1.08 gm. Correspondingly, the additives may then have a normalize weight percentage of: 1) TeO2 at 1.00 and Al2O3 at 0.48; 2) SnCl2 at 1.21 and Al2O3 at 0.81; 3) SnCl2 at 1.18 and SiO2 at 0.28. These examples may correspond to examples 3, 16, and 21 in the above table 6.

FIGS. 11A-11C show graphs illustrating absorption in the visible and infrared wavelengths for vanadium based frits according to certain example embodiments. As shown in the graphs, example vanadium based frits may have absorption of at least 90% across a substantial breath of the visible and IR spectrum. In certain example embodiments the absorption may be about 95%. As discussed in co-pending application Ser. No. 12/929,874, filed on Feb. 22, 2011, entitled “IMPROVED FRIT MATERIALS AND/OR METHOD OF MAKING VACUUM INSULATING GLASS UNITS INCLUDING THE SAME”, the entire contents of which are incorporated herein by reference, frit materials with high visible/IR absorption may be advantageous.

FIG. 11A shows the absorption properties of a vanadium based frit with TeO₂ and Al₂O₃ used as additives (e.g., Ex. 3 of Table 6). FIG. 11B shows the absorption properties of a vanadium based frit with SnCl₂ and Al₂O₃ used as additives (e.g., Ex. 16 of Table 6). FIG. 11C shows the absorption properties of a vanadium based frit with SnCl₂ and SiO₂ used as additives (e.g., Ex. 21 of Table 6).

In certain example embodiments, the application of IR energy to a frit material may be based on a heating profile where the IR energy applied to the frit varies over time. Exemplary heating profiles may be found in co-pending application Ser. No. 12/929,874, the entire contents of which are incorporated herein by reference.

In certain example embodiments, a base composition may be augmented by 3 or 4 additives. For example, a batch for a base composition (in grams) may include V₂O₅ at 52.5, BaO at 22.5, ZnO at 10. Accordingly, three and/or more additives from among TeO2, SnCl2, Al2O3, and SiO2 may be selected to augment the base composition. The ranges (in grams) for the additives may vary between 0 to 7.5 grams per additive. Thus, on a normalized molar percentage the above additives may be included at between 0% and 6%. Thus, the normalized molar percentage of a base composition may be V₂O₅ at between about 43% and 50%, BaO between about 22% and 26%, ZnO between about 18% and 22%. In certain example embodiments, additives (on a normalized molar basis) of TeO2 at around 2%, SnCl2 around 2%, Al2O3 around 2%, and SiO2 around 4% may be added to the base composition.

The techniques, compositions, etc. disclosed herein may be used other methods and/or systems for forming a VIG unit. For example, a vanadium based frit may be used to form an edge seal of a VIG unit. Systems, apparatuses, and/or methods used for creating a VIG unit may be described in co-pending application Ser. No. 12/929,876, filed on Feb. 22, 2011, entitled “LOCALIZED HEATING TECHNIQUES INCORPORATING TUNABLE INFRARED ELEMENT(S) FOR VACUUM INSULATING GLASS UNITS, AND/OR APPARATUSES FOR THE SAME”, the entire contents of which are hereby incorporated by reference.

Certain example embodiments may include three or more additives to a base composition that includes vanadium pentaoxide; barium carbonate that coverts in whole or in part to barium oxide; and zinc oxide. The above three “base” frit elements may be included at 35-55% molar for V₂O₅, 15-35% for BaO, and 15-25% molar for ZnO or, more preferably, 40-50% molar for V₂O₅, 20-30% for BaO, and 18-22% molar for ZnO.

Along with an example base frit composition, one or more additives may be added. The additives may include, for example:

• 1) SnCl₂ at between 1-10% molar, which may help reduce glass softening temperatures and/or reduce crystallization in certain example embodiments;
• 2) CuCl₂ at between 1-5% molar, which may help reduce glass softening temperature in certain example embodiments;
• 3) MoO₃ at between 1-6% molar, which may help reduce glass softening temperatures in certain example embodiments;
• 4) TeO₂ at between 1-10% molar, which may help increase glass flow ability and/or wetting to a substrate glass in certain example embodiments;
• 5) Ta₂O₅ at between 0.5-5% molar, which may help increase softening temperature and/or increase crystallization temperature in certain example embodiments;
• 6) Nb₂O₅ at between 0.5-6% molar, which may help increase softening temperature and/or increase crystallization temperature in certain example embodiments;
• 7) Al₂O₃ at between 0.5-5% molar, which may help increase softening, weathering ability, chemical durability, and/or mechanical strength in certain example embodiments;
• 8) SiO₂ at between 0.5-5% molar, which may help increase softening, weathering ability, chemical durability, and/or mechanical strength in certain example embodiments; and
• 9) CsCO₃ at between 0.5-4% molar, which may help increase melt flow and/or reduce wetting ability in certain example embodiments.

In certain example embodiments, four or more additives, more preferably six or more additives may be added to the above base composition. It will be appreciated that as the number of the additives increases, the interactions between the various additives may produce different results based on the relative weighting of one or more additives (or the base composition). It also will be appreciated that the increased number of additives may create synergistic effects (e.g., in terms of glass softening temperature, flowability, and/or other adjustments) that otherwise might not be observable.

In certain example embodiments, one or more additives may be introduced through the frit creation process rather than being expressly introduced. For example, additive ingredients may be introduced into a frit material as a result of firing the frit material in a crucible. For instance, some ingredients may be “leached” from the crucible and into the frit material. In certain example embodiments, Al₂O₃ and SiO₂ may be leached by this process.

Tables 7-10 show example frit compositions according to certain example embodiments. The different tables each include one or more additives that are varied while the other ingredients are kept substantially the same between the example compounds of the give table.

In tables 7A-7C, molybdenum oxide is varied between the example compounds; in tables 8A-8C tellurium oxide is varied between the example compounds; in tables 9A-9C cesium carbonate is varied between the example compounds; and in tables 10A-10D tantalum oxide and niobium oxide are varied between the example compounds.

Tables 7A, 8A, 9A, and 10A show the example frit compositions by normalized weight percentage. Tables 7B, 8B, 9B, and 10B show the example frit compositions by normalized mole percent. The values given in tables 7-10 A and B are normalized to approximately 100% for shown compositions. For example, V₂O₅ from example 1 in table 7A is 54.88% by weight of the frit composition for the frit composition. Similarly, V₂O₅ for the same example frit composition is shown as 49.76% mole of the resulting frit composition (e.g., from Table 7B). Thus, the normalized weight and mole percentages may add up to about 100% for the example frit compositions shown in the various tables herein. Tables 7C, 8C, 9C, 10C, and 10D show exemplary results for the example frit compositions. As can be seen in the results of the above noted tables (e.g., tables 7-10), performance of one or more of the above examples may be improved over a base frit material, or a frit material with only one additive as discussed above. For example, example frit materials 9 and 11 shown in Table 8 show good flow at 375 degrees C. (5 and 6.5, respectively).

TABLE 7A
MoO3 Examples
	Normalized Weight Percentage
Example	V2O5	BaO	ZnO	MoO3	TeO2	Ta2O5	Al2O3	SiO2	Nb2O5
1	54.88	26.61	10.45	0.87	4.15	1.38	0.00	0.00	1.65
2	54.64	26.49	10.41	1.31	4.13	1.37	0.00	0.00	1.64
3	54.39	26.38	10.36	1.75	4.11	1.37	0.00	0.00	1.64
4	54.15	26.26	10.31	2.19	4.10	1.36	0.00	0.00	1.63
5	53.91	26.14	10.27	2.63	4.08	1.36	0.00	0.00	1.62
6	53.67	26.02	10.22	3.07	4.06	1.35	0.00	0.00	1.62

TABLE 7B
MoO3 Examples
	Normalized Moles of Batch Composition
Ex.	V2O5	BaO	ZnO	MoO3	TeO2	Ta2O5	Al2O3	SiO2	Nb2O5
1	49.76%	22.24%	21.18%	0.99%	4.29%	0.51%	0.00%	0.00%	1.02%
2	49.50%	22.12%	21.08%	1.50%	4.27%	0.51%	0.00%	0.00%	1.02%
3	49.25%	22.01%	20.97%	2.00%	4.24%	0.51%	0.00%	0.00%	1.01%
4	49.00%	21.90%	20.86%	2.50%	4.22%	0.51%	0.00%	0.00%	1.01%
5	48.75%	21.79%	20.75%	3.00%	4.20%	0.50%	0.00%	0.00%	1.00%
6	48.50%	21.67%	20.65%	3.50%	4.18%	0.50%	0.00%	0.00%	1.00%

TABLE 7C
MoO3 Examples
	Test Results
			375 C.		400 C.
	Slides	Slides	13 mm		13 mm
	350 C.	375 C.	button		button
Ex.	15 min	15 min	20 min	Results	20 min	Results
1	5.0	5.5	12.39	glass	13.76	light
						haze
2	3.0	4.5	12.80	glass	14.06	light
						haze
3	4.0	5.5	12.51	glass	14.14	light
						haze
4	4.5	5.0	13.08	glass	14.22	light
						haze
5	5.5	5.0	12.93	glass	14.26	light
						haze
6	5.5	5.5	12.88	glass	14.50	light
						haze

TABLE 8A
TeO2 Examples
	Normalized Weight Percentage
Example	V2O5	BaO	ZnO	MoO3	TeO2	Ta2O5	Al2O3	SiO2	Nb2O5
7	54.84	26.59	10.45	2.67	2.42	1.38	0.00	0.00	1.65
8	54.56	26.46	10.39	2.66	2.91	1.37	0.00	0.00	1.64
9	54.29	26.33	10.34	2.65	3.39	1.37	0.00	0.00	1.63
10	54.02	26.19	10.29	2.63	3.88	1.36	0.00	0.00	1.63
11	53.74	26.06	10.24	2.62	4.37	1.35	0.00	0.00	1.62
12	53.47	25.93	10.18	2.61	4.86	1.34	0.00	0.00	1.61
13	53.20	25.80	10.13	2.59	5.34	1.34	0.00	0.00	1.60
14	52.92	25.66	10.08	2.58	5.83	1.33	0.00	0.00	1.59

TABLE 8B
TeO2 Examples
	Normalized Moles of Batch Composition
Ex.	V2O5	BaO	ZnO	MoO3	TeO2	Ta2O5	Al2O3	SiO2	Nb2O5
7	49.61%	22.17%	21.12%	3.06%	2.50%	0.51%	0.00%	0.00%	1.02%
8	49.36%	22.06%	21.01%	3.04%	3.00%	0.51%	0.00%	0.00%	1.02%
9	49.11%	21.95%	20.91%	3.03%	3.50%	0.51%	0.00%	0.00%	1.01%
10	48.85%	21.83%	20.80%	3.01%	4.00%	0.51%	0.00%	0.00%	1.01%
11	48.59%	21.72%	20.69%	2.99%	4.50%	0.50%	0.00%	0.00%	1.00%
12	48.34%	21.60%	20.58%	2.98%	5.00%	0.50%	0.00%	0.00%	1.00%
13	48.09%	21.49%	20.47%	2.96%	5.50%	0.50%	0.00%	0.00%	0.99%
14	47.83%	21.38%	20.36%	2.95%	6.00%	0.49%	0.00%	0.00%	0.98%

TABLE 8C
TeO2 Examples
	Test Results
			375 C.		400 C.
	Slides	Slides	13 mm		13 mm
	350 C.	375 C.	button		button
Ex.	15 min	15 min	20 min	Results	20 min	Results
7	5.5	6.0	12.89	glass	14.37	haze
8	3.0	6.5	13.08	glass	14.63	light
						haze
9	3.0	5.0	13.38	glass	14.93	light
						haze
10	6.5	5.0	13.17	glass	14.66	light
						haze
11	4.5	6.5	13.04	glass	14.72	glass
12	6.0	6.5	12.72	glass	14.53	light
						haze
13	5.5	5.0	12.94	glass	14.59	light
						haze
14	5.5	6.0	13.24	glass	14.92	light
						haze

TABLE 9A
CsCO3 Examples
	Normalized Weight Percentage
Example	V2O5	BaO	ZnO	MoO3	TeO2	Ta2O5	Al2O3	SiO2	Nb2O5	CsCO3
15	52.95	25.68	10.09	2.58	4.31	1.33	0.00	0.00	1.59	1.47
16	52.69	25.55	10.04	2.57	4.29	1.32	0.00	0.00	1.59	1.97
17	52.43	25.43	9.99	2.56	4.26	1.32	0.00	0.00	1.58	2.44
18	52.17	25.30	9.94	2.54	4.24	1.31	0.00	0.00	1.57	2.92
19	51.91	25.17	9.89	2.53	4.22	1.31	0.00	0.00	1.56	3.41
20	51.65	25.05	9.84	2.52	4.20	1.30	0.00	0.00	1.55	3.89

TABLE 9B
CsCO3 Examples
	Normalized Moles of Batch Composition (%)
Ex.	V2O5	BaO	ZnO	MoO3	TeO2	Ta2O5	Al2O3	SiO2	Nb2O5	CsCO3
15	48.23	21.55	20.53	2.97	4.47	0.50	0.00	0.00	0.99	0.75
16	48.11	21.50	20.48	2.96	4.46	0.50	0.00	0.00	0.99	1.00
17	47.99	21.45	20.43	2.96	4.45	0.50	0.00	0.00	0.99	1.25
18	47.87	21.39	20.38	2.95	4.44	0.50	0.00	0.00	0.99	1.50
19	47.74	21.34	20.33	2.94	4.43	0.49	0.00	0.00	0.98	1.75
20	47.62	21.28	20.27	2.93	4.41	0.49	0.00	0.00	0.98	2.00

TABLE 9C
CsCO3 Examples
	Test Results
			13 mm		13 mm
	Slide	Slide	button -		button -
	350 C. -	375 C. -	375 C.		400 C.
Ex.	15 min	15 min	20 min	Results	20 min	Results
15	5.5	6.5	13.40	glass	14.88	haze
16	5.5	5.5	13.05	glass	15.40	glass
17	4.0	6.5	13.60	glass	15.17	light
						haze
18	4.5	6.5	13.33	glass	14.81	haze
19	6.0	4.5	13.28	glass	14.59	haze
20	4.5	7.0	13.97	glass	16.36	light
						haze

TABLE 10A
Ta2O5 and Nb2O5 Examples
	Normalized Weight Percentage
Example	V2O5	BaO	ZnO	MoO3	TeO2	Ta2O5	Al2O3	SiO2	Nb2O5
21	53.87	26.12	10.26	2.63	3.37	1.34	0.00	0.00	2.41
22	53.42	25.90	10.18	2.60	3.34	1.34	0.00	0.00	3.22
23	52.98	25.69	10.09	2.58	3.31	1.33	0.00	0.00	4.01
24	53.59	25.99	10.21	2.61	3.35	2.65	0.00	0.00	1.60
25	53.15	25.77	10.12	2.59	3.32	2.65	0.00	0.00	2.39
26	52.71	25.56	10.04	2.57	3.29	2.65	0.00	0.00	3.18
27	52.28	25.35	9.96	2.55	3.27	2.63	0.00	0.00	3.97
28	52.86	25.63	10.07	2.58	3.30	3.97	0.00	0.00	1.59
29	52.43	25.43	9.99	2.56	3.28	3.94	0.00	0.00	2.38
30	52.00	25.21	9.90	2.54	3.25	3.94	0.00	0.00	3.16
31	51.57	25.01	9.82	2.51	3.22	3.93	0.00	0.00	3.93

TABLE 10B
Ta2O5 and Nb2O5 Examples
	Normalized Moles of Batch Composition
Ex.	V2O5	BaO	ZnO	MoO3	TeO2	Ta2O5	Al2O3	SiO2	Nb2O5
21	48.87%	21.84%	20.81%	3.01%	3.48%	0.50%	0.00%	0.00%	1.50%
22	48.61%	21.73%	20.70%	3.00%	3.46%	0.50%	0.00%	0.00%	2.00%
23	48.37%	21.62%	20.59%	2.98%	3.44%	0.50%	0.00%	0.00%	2.50%
24	48.87%	21.84%	20.81%	3.01%	3.48%	1.00%	0.00%	0.00%	1.00%
25	48.62%	21.73%	20.70%	3.00%	3.46%	1.00%	0.00%	0.00%	1.50%
26	48.37%	21.62%	20.59%	2.98%	3.44%	1.00%	0.00%	0.00%	2.00%
27	48.12%	21.51%	20.49%	2.96%	3.43%	1.00%	0.00%	0.00%	2.50%
28	48.62%	21.73%	20.70%	3.00%	3.46%	1.50%	0.00%	0.00%	1.00%
29	48.37%	21.62%	20.59%	2.98%	3.44%	1.50%	0.00%	0.00%	1.50%
30	48.12%	21.50%	20.49%	2.96%	3.43%	1.50%	0.00%	0.00%	2.00%
31	47.87%	21.39%	20.38%	2.95%	3.41%	1.50%	0.00%	0.00%	2.50%

TABLE 10C
Ta2O5 and Nb2O5 Examples
	Test Results
			13 mm		13 mm
	Slide	Slide	button -		button -
	350 C. -	375 C. -	375 C.		400 C.
Ex.	15 min	15 min	20 min	Results	20 min	Results
21	4.5	6.5	13.24	glass	15.21	glass
22	4.0	6.5	12.42	glass	14.50	glass
23	2.5	6.0	12.24	glass	14.55	glass
24	4.5	6.5	12.56	glass	14.47	glass
25	3.0	5.0	12.35	glass	14.16	glass
26	4.5	6.0	12.19	glass	14.88	glass
27	4.5	5.0	12.30	glass	14.48	glass
28	3.0	5.5	12.16	glass	14.34	glass
29	3.0	5.5	11.62	glass	14.07	glass
30	3.0	5.5	11.79	glass	14.20	glass
31	3.0	6.0	11.77	glass	13.96	glass

TABLE 10D
Ta2O5 and Nb2O5 Examples
	Test Results Continued
		13 mm button -
	Example	425 C. 20 min	Result
	21	16.07	Haze
	22	15.86	Haze
	23	16.08	light haze
	24	14.79	Haze
	25	15.99	Glass
	26	16.40	light haze
	27	16.15	light haze
	28	15.33	Haze
	29	15.55	Glass
	30	15.71	light haze
	31	14.57	Haze

In certain example embodiments, the use of Ta₂O₅ and/or Nb₂O₅ may help reduce the crystallization of the frit material. As the percentage of contribution by such additives increases, the softening temperature (e.g., a temperature at which the frit material may flow) may also increase. In certain example embodiments, such properties may be desirable for a tip off seal in a VIG unit (e.g., sealing the vacuum hole in a VIG unit).

Frit materials used for tipping off a vacuum hole may have different desirable properties than frit materials for a perimeter seal for a VIG unit. For example, a frit material used in a tip off seal may be completely or substantially exposed to IR and therefore may reach a higher temperature than that of a perimeter seal. Conversely, the perimeter seal may have the glass absorb some percentage of the SWIR directed at the frit of a perimeter seal (e.g., 10%-30% of the SWIR). Thus, an exemplary frit material (e.g., example 21) may be used for a perimeter seal while example 26 may be used for tip off seal.

As shown in Table 10D, the example frit compositions may provide increased resistance, or greater tolerance, to crystallization. The example compositions shown in Tables 7-10 were done in an alumina crucible. With such a crucible, a certain amount of Al₂O₃ and SiO₂ may be “leached” from the crucible during the frit preparation process. Thus, while Al₂O₃ and SiO₂ may not be shown in the above tables 7-10, these additives (or others depending on the crucible type) may yet be present in the frit composition due to the leaching process from the crucible. The leaching of Al₂O₃ and SiO₂ may be a result of melting or firing the frit compositions at certain temperatures (e.g., 800 C. degrees C., 1000 degrees C., etc). Different firing temperatures and/or different lengths of time of firing may affect the amount of material leached from the crucible. The variation of Al₂O₃ and SiO₂ may change the frit performance for sealing at 375 degrees C. and 400 degrees C.

In certain example embodiments, Al₂O₃ may be included in a frit material at between 0% and 2% normalized moles by composition, or at a normalized weight percentage between 0% and 1.2%, or more preferably about 0.8%. SiO₂ may be included at between 1 and 5% normalized mole by composition and/or between about 0.5 and 2% by weight, and more preferably about 1.2% by normalized weight. The inventor has determined that in certain instances, having SiO₂ or Al₂O₃ in amount greater than about 2-5%, resulted in undesirable flow qualities of the frit composition. In particular, when bonding to an example glass substrate, in certain instances, higher percentages of SiO₂ or Al₂O₃ (e.g., in excess of 2 or 4%) resulted in concrete like qualities for the final frit composition.

Table 11 shows example results in a platinum crucible. Such a crucible may reduce or even prevent the leaching of excess additives during the firing process of the frit material.

TABLE 11
Platinum Crucible - Normalized Moles (%)
V2O5	BaO	ZnO	CuCl	SnCl2	TeO2	Ta2O5	Al2O3	SiO2	Nb2O5
44.56	21.96%	18.21%	1.42%	4.66%	3.88%	0.47%	1.19%	2.73%	0.93%
44.25	21.81%	18.09%	1.41%	4.62%	3.85%	0.46%	1.20%	3.38%	0.92%
43.95	21.66%	17.96%	1.40%	4.59%	3.83%	0.46%	1.19%	4.05%	0.91%
44.38	21.87%	18.14%	1.41%	4.64%	3.86%	0.46%	1.60%	2.71%	0.92%
44.08	21.72%	18.02%	1.40%	4.61%	3.84%	0.46%	1.59%	3.36%	0.92%
43.78	21.57%	17.89%	1.39%	4.57%	3.81%	0.46%	1.58%	4.03%	0.91%
44.20	21.78%	18.07%	1.41%	4.62%	3.85%	0.46%	1.99%	2.70%	0.92%
43.89	21.63%	17.94%	1.40%	4.59%	3.82%	0.46%	1.99%	3.38%	0.91%
43.60	21.48%	17.82%	1.39%	4.56%	3.80%	0.46%	1.98%	4.01%	0.91%

FIGS. 12A-12C are graphs summarizing flow characteristics of example frit materials according to certain example embodiments.

FIG. 12A shows that, at 375 degees C., increasing TaO₂O₅ percentage may cause an increase in the initial softening temperature and resulting reduction in the flow (e.g., the diameter of the 1.3 mm button) for the example fit material. In certain example embodiments, increasing Nb₂O₅ percentage may provide less of a reduction in flow. As noted above, a frit (e.g., Ex. 21) with this composition may be used for a perimeter seal of a VIG unit.

FIG. 12B shows that, at 400 degrees C., Ex. 21 has improved flow characteristics. For example, with 1.0% Ta₂O₅, the frit flows well.

FIG. 12C shows, at 425 degrees C., Ex. 21 continuing to flow at higher temperatures, although, as shown above in Table 10D, the fit composition may become crystallized at such a temperature. However, Ex. 26 may continue to have good flow and has only a slight crystallization. Accordingly, Ex. 26 may continue to flow at higher temperatures.

It will be appreciated by those skilled in the art that CTE adjustments may be carried out on the overall frit material (e.g., the compound) for the glass wetting and bonding properties of the frit to cooperate with an underlying substrate (e.g., a glass substrate). In certain example embodiments, CTE matching compounds may be added for these and/or other purposes.

It will be appreciated that one or more metal oxide, chloride, and/or fluoride additives may be used as additives in different embodiments of this invention. Furthermore, in certain example implementations, the metal oxide, chloride, and/or fluoride additives may be stoichiometric or sub-stoichiometric.

As used herein, the terms “on,” “supported by,” and the like should not be interpreted to mean that two elements are directly adjacent to one another unless explicitly stated. In other words, a first layer may be said to be “on” or “supported by” a second layer, even if there are one or more layers there between.

While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not to be limited to the disclosed embodiment, but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.

Claims

1. A vacuum insulated glass (VIG) window unit, comprising: first and second substantially parallel, spaced apart thermally tempered glass substrates;an edge seal provided around a periphery of the first and second thermally tempered glass substrates to form a hermetic seal therebetween and at least partially defining a gap between the first and second thermally tempered glass substrates,wherein the gap of the vacuum insulated glass (VIG) window unit is provided at a pressure less than atmospheric,wherein the edge seal is formed from a frit material at least initially having a composition comprising zinc oxide and:

2. The VIG unit of claim 1, wherein the frit material has a melting temperature less than or equal to 400 degrees C.

3. A vacuum insulated glass (VIG) window unit, comprising: first and second substantially parallel, spaced apart glass substrates;an edge seal provided around a periphery of the first and second glass substrates to form a hermetic seal therebetween and at least partially defining a gap between the first and second glass substrates,wherein the gap of the vacuum insulated glass (VIG) window unit is provided at a pressure less than atmospheric,wherein the edge seal is formed from a frit material at least initially having a composition comprising zinc oxide and: