阅读说明：本技术 一种无碱玻璃组合物、无碱玻璃及制备方法和应用 (Alkali-free glass composition, alkali-free glass, preparation method and application ) 是由 李青 李赫然 张广涛 胡恒广 史伟华 闫冬成 王俊峰 刘华东 于 2020-11-26 设计创作，主要内容包括：本公开涉及一种无碱玻璃组合物、无碱玻璃及其制备方法和应用。以组合物总重量为基准,该无碱玻璃组合物包含：58-63重量％的SiO_2、18-22重量％的Al_2O_3、1-4重量％的MgO、4-6重量％的CaO、0.1-2重量％的SrO、9-14重量％的BaO、0.4-1.5重量％的ZnO、0.2-0.3重量％的SnO_2、0.01-3重量％的NH_4Cl；其中,所述无碱玻璃组合物含或不含碱金属氧化物,所述碱金属氧化物包括Li_2O、Na_2O和K_2O中的一种或几种,所述碱金属氧化物的总含量小于0.05重量％,该无碱玻璃组合物实质上不含B_2O_3。本公开提供的无碱玻璃机械强度高、耐热稳定性高、易于均化澄清。(The disclosure relates to an alkali-free glass composition, alkali-free glass, and a preparation method and application thereof. The alkali-free glass composition comprises, based on the total weight of the composition: 58-63% by weight of SiO 2 18-22% by weight of Al 2 O 3 MgO in 1-4 wt%, CaO in 4-6 wt%, SrO in 0.1-2 wt%, BaO in 9-14 wt%, ZnO in 0.4-1.5 wt% and SnO in 0.2-0.3 wt% 2 0.01 to 3 wt% of NH 4 Cl; wherein the alkali-free glass composition contains or does not contain an alkali metal oxide including Li 2 O、Na 2 O and K 2 One or more of O, the total content of alkali metal oxides is less than 0.05 wt%, and the alkali-free glass composition does not substantially contain B 2 O 3 . The alkali-free glass provided by the disclosure has high mechanical strength, high heat-resistant stability and easy homogenization and clarification.)

1. An alkali-free glass composition, comprising, based on the total weight of the composition: 58-63% by weight of SiO₂18-22% by weight of Al₂O₃MgO in 1-4 wt%, CaO in 4-6 wt%, SrO in 0.1-2 wt%, BaO in 9-14 wt%, ZnO in 0.4-1.5 wt% and SnO in 0.2-0.3 wt%₂0.01 to 3 wt% of NH₄Cl; wherein the alkali-free glass composition contains or does not contain an alkali metal oxide including Li₂O、Na₂O and K₂One or more of O, the total content of alkali metal oxides is less than 0.05 wt%, and the alkali-free glass composition is substantially free of B₂O₃。

2. The alkali-free glass composition of claim 1, wherein the alkali-free glass composition comprises, based on the total weight of the composition: 59-62% by weight of SiO₂19-20% by weight of Al₂O₃1.8-3 wt% of MgO, 4.5-6 wt% of CaO, 0.3-1.2 wt% of SrO, 9.5-12 wt% of BaO, 0.5-1 wt% of ZnO, 0.21-0.27 wt% of SnO₂And 0.1 to 1.0 wt.% NH₄Cl。

3. The alkali-free glass composition of claim 1, wherein, in weight percent:

a value obtained by calculation according to formula (1) is 6.8 to 8.0, preferably 7.4 to 7.8, and further preferably 7.4 to 7.64;

A＝11.13×SiO₂+6.94×Al₂O₃-3.18×B₂O₃17.97 XMgO-12.86 XCaO-28.43 XSrO +6.52 XBaO-5.3 XZnO formula (1);

a B value obtained by calculation according to formula (2) is 12.0 to 35.0, preferably 13 to 18.6, and more preferably 13 to 16.5;

B＝6.25×SiO₂+14.8×Al₂O₃-402.3×B₂O₃+5.7×MgO+4.2×CaO-49.5×SrO+52.2×BaO+21.7×ZnO+803.4×NH₄cl formula (2);

in the formulae (1) and (2), SiO₂、Al₂O₃、MgO、CaO、SrO、BaO、ZnO、NH₄Each Cl represents the weight percent of the corresponding component in the alkali-free glass composition.

4. The alkali-free glass composition of claim 1, wherein the SiO in the alkali-free glass composition is based on the total weight of the composition₂With Al₂O₃The total content of (A) is 76 wt% or more; preferably from 79 to 83 wt%; more preferably 80 to 82 wt%;

optionally, the alkali-free glass composition has R' O not less than 16 wt% based on the total weight of the composition; preferably, R' O is greater than or equal to 17 wt%; more preferably, 18 wt% or more and R' O or less 22 wt% or less; more preferably, 18.5 wt% or more and 19.5 wt% or less of R' O; wherein, the R' O is the total content of MgO, CaO, SrO, BaO and ZnO.

5. A method of making alkali-free glass, comprising the steps of:

the alkali-free glass is obtained by carrying out melting treatment, clarification treatment, molding treatment, annealing treatment and mechanical processing treatment on the alkali-free glass composition according to any one of claims 1 to 4 in sequence.

6. The preparation method according to claim 5, characterized in that, in the melting treatment, the melting temperature is less than or equal to 1650 ℃, preferably, the melting temperature is less than or equal to 1610 ℃; the melting time is more than or equal to 1h, and preferably, the melting time is 2-8 h; the melt viscosity is more than or equal to 400 poise, preferably, the melt viscosity is 400 poise and 600 poise;

in the clarification treatment, the clarification temperature is less than or equal to 1640 ℃, preferably, the clarification temperature is 1600-; clear viscosity is more than or equal to 300 poise, preferably, clear viscosity is 300 poise and 500 poise;

in the annealing treatment, the annealing temperature is more than or equal to 750 ℃, and preferably, the annealing temperature is more than or equal to 805 ℃; the annealing time is more than or equal to 0.1h, and preferably, the annealing time is 0.5-4 h.

7. The alkali-free glass produced by the method of claim 5 or 6.

8. The alkali-free glass according to claim 7, wherein the content of chlorine in the alkali-free glass is 0.05 wt% or more, preferably 0.1 to 0.4 wt%.

9. The alkali-free glass of claim 7, wherein the alkali-free glass has a density of less than 2.65g/cm³A coefficient of thermal expansion in the range of 20 to 300 ℃ of less than 40 x 10^-7V DEG C, Young's modulus of more than 82GPa, strain point temperature T_stAt a temperature of 750 ℃ or more and an annealing point temperature T_aIs above 800 ℃; liquidus temperature T_LBelow 1200 ℃; liquidus viscosity η_LIs more than 350 kpoise; a temperature T corresponding to a viscosity of 200 poise₂₀₀Is below 1680 ℃; temperature T corresponding to viscosity of 35000 poise₃₅₀₀₀Below 1330 ℃; transmittance at wavelength of 308nm is above 70%; the corrosion rate of the hydrofluoric acid CHF is 7.0mg/cm²The following; stress test maximum stress sigma_maxIs below 110 psi; a standard deviation of the stress test STDEV of 30psi or less; the content of gaseous inclusions with the equivalent spherical diameter (D.EQ.) larger than 0.02mm is less than 0.5 inclusions/Kg of glass;

preferably, the alkali-free glass has a density of less than 2.62g/cm³(ii) a A coefficient of thermal expansion of less than 38.5 x 10 in the range of 20-300 DEG C^-7/° c; young's modulus of 83.4GPa or more; strain point temperature T_stIs 754 ℃ or higher; annealing point temperature T_aAbove 805 ℃; liquidus temperature T_LIs 1180 ℃ or lower; liquidus viscosity η_LMore than 385 kpoise; a temperature T corresponding to a viscosity of 200 poise₂₀₀Below 1670 deg.C; temperature T corresponding to viscosity of 35000 poise₃₅₀₀₀Below 1290 ℃; transmittance at wavelength of 308nm is over 74.8%; the corrosion rate of the hydrofluoric acid CHF is 6.2mg/cm²The following; stress test maximum stress sigma_maxBelow 80 psi; a standard deviation of the stress test STDEV of 15psi or less; the content of gaseous inclusions with equivalent spherical diameter (D.EQ.) larger than 0.02mm is less than 0.2 per Kg of glass.

10. Use of the alkali-free glass of any one of claims 7 to 9 in the manufacture of a display device or a solar cell.

Technical Field

The disclosure relates to the field of glass, in particular to an alkali-free glass composition, alkali-free glass, a preparation method and application.

Background

A glass substrate for TFT display panel manufacture needs to form transparent conductive film, insulating film, semiconductor (polysilicon, amorphous silicon, etc.) film and metal film on the glass surface of the substrate by sputtering, Chemical Vapor Deposition (CVD), etc., and then form various circuits and patterns by Photo-etching (Photo-etching) technique if the glass contains alkali metal oxide (Na)₂O，K₂O，Li₂O), alkali metal ions diffusing into the deposited semiconductor material during heat treatment, impairing the semiconductor film characteristics, and therefore the glass should be free of alkali metal oxides, and alkali-free glasses, preferably SiO, must be used₂、Al₂O₃、B₂O₃And alkali-free boroaluminosilicate glasses containing an alkaline earth metal oxide RO (RO ═ Mg, Ca, Sr, Ba) as a main component. At present, with the rapid popularization of portable electronic equipment (such as notebook computers, smart phones and PDAs), higher requirements are put on the light weight of accessories. Therefore, higher requirements are put on the components of the glass substrate so as to ensure the glass substrate to meet the requirements of modern liquid crystal displays. The glass substrate must have the followingThe characteristics are as follows: contains less than l000ppm of alkali metal oxide; has chemical resistance; the thermal expansion coefficient is close to that of silicon of the thin film transistor, and the linear thermal expansion coefficient of 20-300 ℃ is generally required to be (30-40) × 10^-7Between/° c, too high or too low expansion coefficient is not beneficial to improving the yield of the panel manufacturing process; the strain point of the glass is improved to reduce the heat shrinkage; has small density, and is convenient for carrying and holding.

With the popularization of smart phones and tablet computers, an era of intelligent movement is opened. The existing mobile phones are limited to communication functions, but the performance of the existing intelligent devices including the smart phones and the tablet computers is close to that of the notebook computers, so that people can execute and enjoy higher-level business and entertainment activities all the time by virtue of the convenience of wireless communication. Under such a trend, the demand for the performance of the display is increasing, and particularly, the demand for the picture quality of the mobile smart device and the outdoor visibility is also increasing, and the weight is becoming lighter and the thickness is becoming thinner, which is an inevitable trend in order to reduce the burden of using the handheld device. Under the guidance of such development trend, the display panel is developing towards light, thin and ultra-high definition display, and on one hand, the glass substrate is required to have smaller density; on the other hand, the panel process is developing to a higher processing temperature; meanwhile, the thickness of the single glass sheet is treated by the process, and the thickness of the single glass sheet reaches 0.25mm, 0.2mm, 0.1mm and 0.05mm or even thinner. The method for thinning glass mainly comprises chemical thinning, specifically, a hydrofluoric acid or hydrofluoric acid buffer solution is used for corroding a glass substrate, and the thinning principle is as follows:

the main chemical reactions are as follows: 4HF + SiO₂＝SiF₄+2H₂O；

Secondary chemical reaction: RO +2H⁺＝R²⁺+H₂O (R represents an alkaline earth metal or the like).

The chemical thinning process and the surface quality of the thinned glass substrate have a certain relation with the composition of basic glass, and poor points such as pits, concave-convex points and the like frequently appear in the conventional TFT-LCD substrate glass in the chemical thinning process, so that the display device after thinning has more failures in the Bending test (for example, 4-Point Bending test) process, and the specific expression is that the Bending stress and the Bending strain can not meet the index requirements. The glass with high chemical stability has better surface quality after being thinned, so that the development of the TFT-LCD substrate glass with high chemical stability can reduce the production cost of secondary polishing and the like, improve the product quality and the yield, and has great benefits for large-scale industrial production. However, too slow a hydrofluoric acid or hydrofluoric acid buffer etch rate may reduce thinning plant production efficiency.

In the field of flat panel displays, handheld display devices and fixed display devices are developing towards high definition. Handheld display devices, such as mobile phones, etc., have mainstream pixel densities in excess of 200ppi, 300ppi, and even 400 ppi; stationary display devices, such as liquid crystal televisions, have resolutions exceeding 2K, 4K, and even 8K. The trend of high definition has raised the requirements for the fineness of the panel process, and further has raised the requirements for the thermal stability and quality of the matching substrate glass. The glass suitable for the display substrate belongs to an alkali-free high-aluminosilicate glass system, has the characteristics of high strain point, high-temperature viscosity and large surface tension, is obviously higher than common soda-lime glass in manufacturing difficulty, is difficult to reach an ideal level in high-temperature homogenization, and is easy to form glassy inclusions which appear in strips with different thicknesses and depths and influence the terminal display effect; on the other hand, the stress dispersion of the test sample is found to be large in the stress test process, and the quality guarantee of batch supply is influenced.

There are various methods in the prior art for improving the high temperature homogenization of high viscosity glass. One approach is to reduce the viscosity of the high temperature glass melt. In the method, the glass melt with lower viscosity has higher temperature, which is beneficial to reducing viscous resistance in the homogenization process, thereby being beneficial to ion diffusion and obtaining a glass homogeneous body with good homogenization degree; however, the method has some defects, on one hand, the substrate glass has the characteristics of high-temperature viscosity and large surface tension, the viscosity of the glass melt for removing residual gaseous inclusions in the glass melt in the prior art is about 100 poise generally, the corresponding melt temperature under the viscosity is usually 1650 ℃, 1700 ℃ or even above 1750 ℃, and the high-temperature is continuously reducedThe viscosity of the glass melt can cause further temperature rise, so that the reaction between the glass and the refractory material is aggravated, and further great challenges are brought to the temperature resistance and the service life of the matched refractory material; on the other hand, the melting vessel of the above glass melt is often made of ZrO₂High-zirconium bricks with a content of more than 80% constitute a potential risk source for high-temperature erosion and spalling of the refractory material (for example, zirconia) to create defects inside the glass.

Another approach is to extend the holding time of the glass melt at low viscosity. The method is beneficial to the ion diffusion in the glass melt for a longer time, but the method has the problems of higher cost and lower manufacturing yield. On one hand, the heat preservation time under low viscosity is prolonged, the length of process hardware needs to be increased or the glass melt advancing speed needs to be reduced, and the two modes bring adverse effects on the service life of the hardware and the manufacturing efficiency; on the other hand, the erosion reaction between the glass melt and the refractory material and precious metal in the low viscosity (high temperature) state is intensified, and becomes a potential risk source for the generation of solid inclusions in the glass.

Another method is mechanical agitation. The glass melt is forced to be alternately diffused by mechanical stirring, so as to achieve the purpose of homogenization. The method is one of the currently used homogenization methods, but the problem of undesirable homogenization degree still exists in the aspect of homogenization effect, and meanwhile, the erosion reaction among refractory materials, precious metals and glass melt is also accelerated, and the method becomes a potential risk source for generating solid inclusions in glass.

Disclosure of Invention

The purpose of the disclosure is to provide an alkali-free glass composition, alkali-free glass, a preparation method and application. The alkali-free glass provided by the present disclosure has low density, low coefficient of thermal expansion, high mechanical strength, low high temperature viscosity and is easy to homogenize and clarify.

In order to achieve the above object, a first aspect of the present disclosure provides an alkali-free glass composition comprising, based on the total weight of the composition: 58-63% by weight of SiO₂18-22% by weight of Al₂O₃1-4 wt% of MgO, 4-6 wt% of CaO, 0.1-2 wt% of% SrO, 9-14 wt.% BaO, 0.4-1.5 wt.% ZnO, 0.2-0.3 wt.% SnO₂0.01 to 3 wt% of NH₄Cl; wherein the alkali-free glass composition contains or does not contain an alkali metal oxide including Li₂O、Na₂O and K₂One or more of O, the total content of alkali metal oxides is less than 0.05 wt%, and the alkali-free glass composition is substantially free of B₂O₃。

Optionally, the alkali-free glass composition comprises, based on the total weight of the composition: 59-62% by weight of SiO₂19-20% by weight of Al₂O₃1.8-3 wt% of MgO, 4.5-6 wt% of CaO, 0.3-1.2 wt% of SrO, 9.5-12 wt% of BaO, 0.5-1 wt% of ZnO, 0.21-0.27 wt% of SnO₂And 0.1 to 1.0 wt.% NH₄Cl。

Optionally, in weight percent:

a value obtained by calculation according to formula (1) is 6.8 to 8.0, preferably 7.4 to 7.8, and further preferably 7.4 to 7.64;

A＝11.13×SiO₂+6.94×Al₂O₃-3.18×B₂O₃17.97 XMgO-12.86 XCaO-28.43 XSrO +6.52 XBaO-5.3 XZnO formula (1);

a B value obtained by calculation according to formula (2) is 12.0 to 35.0, preferably 13 to 18.6, and more preferably 13 to 16.5;

B＝6.25×SiO₂+14.8×Al₂O₃-402.3×B₂O₃+5.7×MgO+4.2×CaO-49.5×SrO+52.2×BaO+21.7×ZnO+803.4×NH₄cl formula (2);

in the formulae (1) and (2), SiO₂、Al₂O₃、MgO、CaO、SrO、BaO、ZnO、NH₄Each Cl represents the weight percent of the corresponding component in the alkali-free glass composition.

Optionally, the SiO in the alkali-free glass composition is based on the total weight of the composition₂With Al₂O₃The total content of (A) is 76 wt% or more; preferably from 79 to 83 wt%; more preferably 80 to 82Amount%;

optionally, the alkali-free glass composition has R' O not less than 16 wt% based on the total weight of the composition; preferably, R' O is greater than or equal to 17 wt%; more preferably, 18 wt% or more and R' O or less 22 wt% or less; more preferably, 18.5 wt% or more and 19.5 wt% or less of R' O; wherein, the R' O is the total content of MgO, CaO, SrO, BaO and ZnO.

A second aspect of the present disclosure provides a method of making an alkali-free glass, the method comprising the steps of:

the alkali-free glass composition provided by the first aspect of the disclosure is subjected to melting treatment, clarification treatment, molding treatment, annealing treatment and machining treatment in sequence to obtain the alkali-free glass.

Optionally, in the melting treatment, the melting temperature is less than or equal to 1650 ℃, preferably, the melting temperature is less than or equal to 1610 ℃; the melting time is more than or equal to 1h, and preferably, the melting time is 2-8 h; the melt viscosity is more than or equal to 400 poise, preferably, the melt viscosity is 400 poise and 600 poise;

in the clarification treatment, the clarification temperature is less than or equal to 1640 ℃, preferably, the clarification temperature is 1600-; clear viscosity is more than or equal to 300 poise, preferably, clear viscosity is 300 poise and 500 poise;

in the annealing treatment, the annealing temperature is more than or equal to 750 ℃, and preferably, the annealing temperature is more than or equal to 805 ℃; the annealing time is more than or equal to 0.1h, and preferably, the annealing time is 0.5-4 h.

A third aspect of the present disclosure provides alkali-free glass made by the method provided by the second aspect of the present disclosure.

Optionally, the alkali-free glass has a chlorine content of 0.05 wt% or more, preferably 0.1 to 0.4 wt%.

Optionally, the alkali-free glass has a density of less than 2.65g/cm³A coefficient of thermal expansion in the range of 20 to 300 ℃ of less than 40 x 10^-7V DEG C, Young's modulus of more than 82GPa, strain point temperature T_stAt a temperature of 750 ℃ or more and an annealing point temperature T_aIs above 800 ℃; liquidus temperature T_LBelow 1200 ℃; liquidus viscosity η_LIs more than 350 kpoise; a temperature T corresponding to a viscosity of 200 poise₂₀₀Is 168 ofBelow 0 ℃; temperature T corresponding to viscosity of 35000 poise₃₅₀₀₀Below 1330 ℃; transmittance at wavelength of 308nm is above 70%; the corrosion rate of the hydrofluoric acid CHF is 7.0mg/cm²The following; stress test maximum stress sigma_maxIs below 110 psi; a standard deviation of the stress test STDEV of 30psi or less; the content of gaseous inclusions with the equivalent spherical diameter (D.EQ.) larger than 0.02mm is less than 0.5 inclusions/Kg of glass;

preferably, the alkali-free glass has a density of less than 2.62g/cm³(ii) a A coefficient of thermal expansion of less than 38.5 x 10 in the range of 20-300 DEG C^-7/° c; young's modulus of 83.4GPa or more; strain point temperature T_stIs 754 ℃ or higher; annealing point temperature T_aAbove 805 ℃; liquidus temperature T_LIs 1180 ℃ or lower; liquidus viscosity η_LMore than 385 kpoise; a temperature T corresponding to a viscosity of 200 poise₂₀₀Below 1670 deg.C; temperature T corresponding to viscosity of 35000 poise₃₅₀₀₀Below 1290 ℃; transmittance at wavelength of 308nm is over 74.8%; the corrosion rate of the hydrofluoric acid CHF is 6.2mg/cm²The following; stress test maximum stress sigma_maxBelow 80 psi; a standard deviation of the stress test STDEV of 15psi or less; the content of gaseous inclusions with equivalent spherical diameter (D.EQ.) larger than 0.02mm is less than 0.2 per Kg of glass.

A fourth aspect of the present disclosure provides a use of the alkali-free glass of the third aspect in the manufacture of a display device or a solar cell.

By the technical scheme, the alkali-free glass composition is provided, and the alkali-free glass obtained by the alkali-free glass composition has the excellent performances of low density, low thermal expansion coefficient, high mechanical strength, low high-temperature viscosity, easiness in homogenization and clarification and the like. The alkali-free glass provided by the disclosure can be applied to the preparation of substrate glass substrate materials of flat panel display products or glass film layer materials for screen surface protection, substrate glass substrate materials of flexible display products or surface packaging glass materials or glass film layer materials for screen surface protection, substrate glass substrate materials of flexible solar cells, safety glass, bulletproof glass, intelligent automobile glass, intelligent traffic display screens, intelligent show windows and intelligent card tickets and other application fields requiring glass materials with high thermal stability and mechanical stability.

Additional features and advantages of the disclosure will be set forth in the detailed description which follows.

Detailed Description

The endpoints and any values disclosed in the present disclosure are not limited to the precise range or value, and such ranges or values should be understood to encompass values close to those ranges or values. For ranges of values, one or more new ranges of values may be obtained from combinations of values between the endpoints of each range, the endpoints of each range and the individual values, and these ranges of values should be considered as specifically disclosed herein.

In a first aspect, the present disclosure provides an alkali-free glass composition comprising, based on the total weight of the composition: 58-63% by weight of SiO₂18-22% by weight of Al₂O₃MgO in 1-4 wt%, CaO in 4-6 wt%, SrO in 0.1-2 wt%, BaO in 9-14 wt%, ZnO in 0.4-1.5 wt% and SnO in 0.2-0.3 wt%₂0.01 to 3 wt% of NH₄Cl; wherein the alkali-free glass composition contains or does not contain an alkali metal oxide, the alkali metal oxide including Li₂O、Na₂O and K₂One or more of O, a total content of alkali metal oxides of less than 0.05 wt.%, and the alkali-free glass composition being substantially free of B₂O₃。

In the present disclosure, "the alkali-free glass composition does not substantially contain B₂O₃"means that: in the alkali-free glass composition provided by the present disclosure, except for B inevitably introduced in the form of impurities₂O₃The present disclosure does not actively add B in any form₂O₃. The alkali-free glass composition provided by the present disclosure avoids the introduction of B₂O₃The phase separation of the glass is promoted, and the phenomena that the homogenization difficulty of the glass is increased and the low-temperature viscosity of the glass is greatly reduced are caused.

The present disclosure provides alkali-free glass compositions with or without alkali metal oxides, the alkali goldThe metal oxide includes Li₂O、Na₂O and K₂One or more of O, the total alkali metal oxide content in the alkali-free glass compositions provided by the present disclosure is less than 0.05 wt.%, which improves the chemical resistance properties of the alkali-free glass compositions.

The present disclosure provides an alkali-free glass composition, and the alkali-free glass prepared from the alkali-free glass composition has excellent properties of low density, low coefficient of thermal expansion, high mechanical strength, low high-temperature viscosity, and easy homogenization and clarification. The alkali-free glass provided by the disclosure can be applied to the preparation of substrate glass substrate materials of flat panel display products or glass film layer materials for screen surface protection, substrate glass substrate materials of flexible display products or surface packaging glass materials or glass film layer materials for screen surface protection, substrate glass substrate materials of flexible solar cells, safety glass, bulletproof glass, intelligent automobile glass, intelligent traffic display screens, intelligent show windows and intelligent card tickets and other application fields requiring glass materials with high thermal stability and mechanical stability.

In one embodiment, the alkali-free glass composition may comprise 58 wt.% SiO₂58.8% by weight of SiO₂59.3% by weight of SiO₂59.4% by weight of SiO₂59.7% by weight of SiO₂60.4% by weight of SiO₂60.9% by weight of SiO₂61% by weight of SiO₂61.1% by weight of SiO₂61.2% by weight of SiO₂61.3% by weight of SiO₂61.4% by weight and 61.5% by weight of SiO₂61.7% by weight of SiO₂61.8% by weight of SiO₂62.0% by weight of SiO₂62.4% by weight of SiO₂62.7% by weight of SiO₂63% by weight of SiO₂And any weight percent of SiO between any two adjacent weight percent₂。

The disclosure adopts the SiO provided by the above embodiment₂Content of SiO is avoided₂Too low a content is not good for enhancing the chemical resistance and corrosion resistance of the glass, resulting in too high an expansion coefficient, and thus leading to glassThe defect of easy devitrification; at the same time avoid SiO₂The content is too high, so that the high-temperature viscosity of the alkali-free glass substrate is increased, the melting temperature is increased, and the melting is not facilitated, so that the furnace in the common industry is difficult to meet the defects of batch melting, homogenization and clarification of materials by the conventional high-capacity melting technology.

In one embodiment, the alkali-free glass composition may include 18 wt.% Al₂O₃18.4% by weight of Al₂O₃18.8% by weight of Al₂O₃19.1% by weight of Al₂O₃19.2% by weight of Al₂O₃19.3% by weight of Al₂O₃19.4% by weight of Al₂O₃19.5% by weight of Al₂O₃19.6% by weight of Al₂O₃19.7% by weight of Al₂O₃19.8% by weight of Al₂O₃19.9% by weight of Al₂O₃20% by weight of Al₂O₃20.1% by weight of Al₂O₃20.3% by weight of Al₂O₃20.5% by weight of Al₂O₃20.8%, 20.9%, 22% by weight of Al₂O₃And any weight percent of Al between any two adjacent weight percent₂O₃。

The present disclosure adopts the Al provided by the above embodiments₂O₃In an amount of (1) avoiding Al₂O₃The content is too low, so that the heat resistance of the glass is difficult to improve and the glass is easy to be corroded by external moisture and chemical reagents; also avoid Al₂O₃The content is too high, which causes the glass to be easy to generate crystallization phenomenon and the defects that the glass is difficult to melt, homogenize and clarify.

In a specific embodiment, the alkali-free glass composition may comprise 0.4 wt.% ZnO, 0.5 wt.% ZnO, 0.6 wt.% ZnO, 0.7 wt.% ZnO, 0.8 wt.% ZnO, 0.9 wt.% ZnO, 1.0 wt.% ZnO, 1.1 wt.% ZnO, 1.2 wt.% ZnO, 1.3 wt.% ZnO, 1.4 wt.% ZnO, and 1.5 wt.% ZnO, as well as any weight percent of ZnO between any two adjacent weight percent.

The ZnO content provided by the embodiment reduces the crystallization temperature of an alkali-free glass system, inhibits crystallization, reduces the high-temperature viscosity of the glass, is beneficial to eliminating bubbles, and can improve the strength, hardness and chemical resistance of the glass below a softening point and reduce the thermal expansion coefficient of the glass. The phenomenon that the strain point of the glass is greatly reduced due to the excessive content of ZnO in the alkali-free glass, and the thermal stability of the glass substrate is not promoted is avoided.

In a specific embodiment, the alkali-free glass composition may include 1.0 wt.% MgO, 1.1 wt.% MgO, 1.2 wt.% MgO, 1.3 wt.% MgO, 1.4 wt.% MgO, 1.5 wt.% MgO, 1.6 wt.% MgO, 1.7 wt.% MgO, 1.8 wt.% MgO, 1.9 wt.% MgO, 2.0 wt.% MgO, 2.1 wt.% MgO, 2.2 wt.% MgO, 2.3 wt.% MgO, 2.4 wt.% MgO, 2.5 wt.% MgO, 2.7 wt.% MgO, 2.9 wt.% MgO, 3.1 wt.% MgO, 3.3 wt.% MgO, 3.6 wt.% MgO, 3.8 wt.% MgO, 3.9 wt.% MgO, and 4.0 wt.% MgO, and any weight percentage of MgO between any two adjacent weight percentages.

In a particular embodiment, the alkali-free glass composition may include 4.1 wt.% CaO, 4.2 wt.% CaO, 4.3 wt.% CaO, 4.4 wt.% CaO, 4.5 wt.% CaO, 4.6 wt.% CaO, 4.7 wt.% CaO, 4.8 wt.% CaO, 4.9 wt.% CaO, 5.0 wt.% CaO, 5.2 wt.% CaO, 5.4 wt.% CaO, 5.6 wt.% CaO, 5.8 wt.% CaO, 5.9 wt.% CaO, and 6.0 wt.% CaO, and any weight percent amount of CaO between any two adjacent weight percent amounts.

In a specific embodiment, the alkali-free glass composition may comprise 0.1 weight percent SrO, 0.2 weight percent SrO, 0.3 weight percent SrO, 0.4 weight percent SrO, 0.5 weight percent SrO, 0.6 weight percent SrO, 0.7 weight percent SrO, 0.8 weight percent SrO, 0.9 weight percent SrO, 1.0 weight percent SrO, 1.1 weight percent SrO, 1.2 weight percent SrO, 1.4 weight percent SrO, 1.5 weight percent SrO, 1.6 weight percent SrO, 1.7 weight percent SrO, 1.8 weight percent SrO, 1.9 weight percent SrO, 2.0 weight percent SrO, and any weight percent of SrO between any two adjacent weight percent.

In a specific embodiment, the alkali-free glass composition may include 9.0 wt.% BaO, 9.2 wt.% BaO, 9.4 wt.% BaO, 9.6 wt.% BaO, 9.7 wt.% BaO, 9.8 wt.% BaO, 9.9 wt.% BaO, 10.0 wt.% BaO, 10.1 wt.% BaO, 10.2 wt.% BaO, 10.3 wt.% BaO, 10.4 wt.% BaO, 10.5 wt.% BaO, 10.6 wt.% BaO, 10.7 wt.% BaO, 10.8 wt.% BaO, 10.9 wt.% BaO, 11.2 wt.% BaO, 11.4 wt.% BaO, 11.8 wt.% BaO, 12.3 wt.% BaO, 12.6 wt.% BaO, 13.0 wt.% BaO, 13.4 wt.% BaO, 13.0 wt.% BaO, 14.0 wt.% BaO, and any two or more of the adjacent components by weight.

The contents of MgO, CaO, SrO and BaO alkaline earth metals provided by the embodiment effectively reduce the high-temperature viscosity of the alkali-free glass, thereby improving the melting property and the forming property of the glass and improving the strain point of the glass; the chemical stability and mechanical stability of the alkali-free glass substrate are also improved. Meanwhile, the phenomena of increased density of the alkali-free glass substrate and increased incidence of cracks, devitrification and phase separation caused by excessive content of alkaline earth metal oxide are avoided.

In a preferred embodiment, the present disclosure provides an alkali-free glass composition comprising, based on the total weight of the composition: 59-62% by weight of SiO₂19-20% by weight of Al₂O₃1.8-3 wt% of MgO, 4.5-6 wt% of CaO, 0.3-1.2 wt% of SrO, 9.5-12 wt% of BaO, 0.5-1 wt% of ZnO, 0.21-0.27 wt% of SnO₂And 0.1 to 1.0 wt.% NH₄Cl。

The content of each component of the alkali-free glass composition provided by the preferred embodiment is adopted in the present disclosure59-62% by weight of SiO₂The alkali-free glass substrate is favorable for further considering the performances of chemical resistance, mechanical strength, high-temperature viscosity and the like of the alkali-free glass substrate; using 19-20% by weight of Al₂O₃The heat resistance, chemical resistance and mechanical strength of the alkali-free glass substrate are further optimized, and the crystallization performance and homogenization performance are improved; and 0.5-1.0 wt% of ZnO is adopted, so that the crystallization temperature of the alkali-free glass substrate is further reduced, and the uniform stress distribution of the alkali-free glass substrate is ensured. By NH₄Cl and SnO₂The degree of homogenization of the alkali-free glass can be improved.

In one embodiment, the SiO in the alkali-free glass composition is based on the total weight of the composition₂With Al₂O₃The total content of (A) is 76 wt% or more; preferably from 79 to 83 wt%; more preferably 80 to 82 wt%.

The disclosure provides SiO by the above embodiments₂With Al₂O₃The total content of (a) is effective to improve chemical resistance, corrosion resistance, heat resistance, meltability, homogeneity, workability, and mechanical strength of an alkali-free glass substrate produced from the alkali-free glass composition, and to reduce the probability of occurrence of devitrification of the alkali-free glass substrate.

In one embodiment, the alkali-free glass composition has R' O > 16 wt%, based on the total weight of the composition; preferably, R' O is greater than or equal to 17 wt%; more preferably, 18 wt% or more and R' O or less 22 wt% or less; more preferably, 18.5 wt% or more and 19.5 wt% or less of R' O; wherein, the R' O is the total content of MgO, CaO, SrO, BaO and ZnO. According to the invention, the content range of R' O in the embodiment can further improve the performance of the alkali-free glass, and reduce the occurrence rate of density increase, cracks, devitrification and phase separation of the alkali-free glass substrate.

In one embodiment, the present disclosure provides an alkali-free glass composition comprising, in weight percent:

a value obtained by calculation according to formula (1) is 6.8 to 8.0, preferably 7.4 to 7.8, and further preferably 7.4 to 7.64;

A＝11.13×SiO₂+6.94×Al₂O₃-3.18×B₂O₃17.97 XMgO-12.86 XCaO-28.43 XSrO +6.52 XBaO-5.3 XZnO formula (1);

a B value obtained by calculation according to formula (2) is 12.0 to 35.0, preferably 13 to 18.6, and more preferably 13 to 16.5;

B＝6.25×SiO₂+14.8×Al₂O₃-402.3×B₂O₃+5.7×MgO+4.2×CaO-49.5×SrO+52.2×BaO+21.7×ZnO+803.4×NH₄cl formula (2);

in the formulae (1) and (2), SiO₂、Al₂O₃、MgO、CaO、SrO、BaO、ZnO、NH₄Each Cl represents the weight percent of the corresponding component in the alkali-free glass composition.

In the above embodiment, the alkali-free glass composition having the component contents satisfying the ranges of the a value and the B value can give an alkali-free glass having more excellent properties, low density, low thermal expansion coefficient, high mechanical strength, low high-temperature viscosity, and easy homogenization and clarification.

In a second aspect of the present disclosure, there is provided a method of making an alkali-free glass, the method comprising the steps of:

the alkali-free glass composition provided by the first aspect of the disclosure is subjected to melting treatment, clarification treatment, molding treatment, annealing treatment and machining treatment in sequence to obtain the alkali-free glass.

The method for preparing the alkali-free glass provided by the disclosure is simple in process and easy to operate; and the prepared alkali-free glass has low density, low thermal expansion coefficient and high mechanical strength.

In one embodiment, the method of making alkali-free glass provided by the present disclosure has a melting temperature of 1650 ℃ or less, preferably 1610 ℃ or less in the melting process; the melting time is more than or equal to 1h, and preferably, the melting time is 2-8 h; the melt viscosity is more than or equal to 400 poise, preferably, the melt viscosity is 400 poise and 600 poise;

in the clarification treatment, the clarification temperature is less than or equal to 1640 ℃, preferably, the clarification temperature is 1600-; clear viscosity is more than or equal to 300 poise, preferably, clear viscosity is 300 poise and 500 poise;

in the annealing treatment, the annealing temperature is more than or equal to 750 ℃, and preferably, the annealing temperature is more than or equal to 805 ℃; the annealing time is more than or equal to 0.1h, and preferably, the annealing time is 0.5-4 h. In the embodiment, the preparation method disclosed by the invention is mild in process conditions and easy to implement.

In one embodiment, the means of machining comprises: cutting, grinding and polishing the glass product to obtain the glass product with the thickness less than 1 cm; preferably, a glass article having a thickness of 0.5mm or 0.8mm is produced.

In a third aspect of the present disclosure, there is provided an alkali-free glass prepared by the method provided in the second aspect of the present disclosure.

In one embodiment, the alkali-free glass has a chlorine content of 0.05 wt% or more, preferably 0.1 to 0.4 wt%.

In one embodiment, the present disclosure provides an alkali-free glass having a density of less than 2.65g/cm³A coefficient of thermal expansion in the range of 20 to 300 ℃ of less than 40 x 10^-7V DEG C, Young's modulus of more than 82GPa, strain point temperature T_stAt a temperature of 750 ℃ or more and an annealing point temperature T_aIs above 800 ℃; liquidus temperature T_LBelow 1200 ℃; liquidus viscosity η_LIs more than 350 kpoise; a temperature T corresponding to a viscosity of 200 poise₂₀₀Is below 1680 ℃; temperature T corresponding to viscosity of 35000 poise₃₅₀₀₀Below 1330 ℃; transmittance at wavelength of 308nm is above 70%; the corrosion rate of the hydrofluoric acid CHF is 7.0mg/cm²The following; stress test maximum stress sigma_maxIs below 110 psi; a standard deviation of the stress test STDEV of 30psi or less; the content of gaseous inclusions with equivalent spherical diameter (D.EQ.) larger than 0.02mm is less than 0.5 inclusions/Kg of glass.

In a preferred embodiment, the present disclosure provides alkali-free glasses having a density less than 2.62g/cm³(ii) a A coefficient of thermal expansion of less than 38.5 x 10 in the range of 20-300 DEG C^-7/° c; young's modulus of 83.4GPa or more; strain point temperature T_stIs 754 ℃ or higher; annealing point temperature T_aAbove 805 ℃; liquidus temperature T_LIs 1180 ℃ or lower; liquidus viscosity η_LIs 3More than 85 kpoise; a temperature T corresponding to a viscosity of 200 poise₂₀₀Below 1670 deg.C; temperature T corresponding to viscosity of 35000 poise₃₅₀₀₀Below 1290 ℃; transmittance at wavelength of 308nm is over 74.8%; the corrosion rate of the hydrofluoric acid CHF is 6.2mg/cm²The following; stress test maximum stress sigma_maxBelow 80 psi; a standard deviation of the stress test STDEV of 15psi or less; the content of gaseous inclusions with equivalent spherical diameter (D.EQ.) larger than 0.02mm is less than 0.2 per Kg of glass.

A fourth aspect of the present disclosure provides a use of the alkali-free glass provided by the third aspect of the present disclosure in the manufacture of a display device or a solar cell.

The alkali-free glass provided by the disclosure can be used for preparing display devices and solar cells, and is particularly suitable for preparing substrate glass substrate materials of flat panel display products, glass film layer materials for screen surface protection, substrate glass substrate materials of flexible display products, surface packaging glass materials, glass film layer materials for screen surface protection, substrate glass substrate materials of flexible solar cells, safety glass, bulletproof glass, intelligent automobile glass, intelligent traffic display screens, intelligent windows and intelligent card tickets, and other application fields requiring glass materials with high thermal stability and mechanical stability.

The present invention will be described in detail below by way of examples. In the following examples, each material used was commercially available unless otherwise specified, and the method used was a conventional method in the art unless otherwise specified.

Examples 1 to 16 and comparative examples 1 to 4

According to the raw material compositions of the examples and comparative examples shown in the following Table 1, the components were weighed, mixed uniformly, and then heated in a resistance furnace at 1600 ℃ for 10 hours, and slowly stirred at a constant speed using a platinum-rhodium alloy (80 wt% Pt +20 wt% Rh) stirrer, and the melt viscosity was 400-600 poise. Pouring the molten glass into a stainless steel cast iron mold, clarifying at the temperature of 1600-1635 ℃ and the viscosity of 300-500 poise, and then forming to obtain a block glass product; the glass article was then annealed in an annealing furnace at 785-815 ℃ for 2 hours. The power is turned off and the furnace is cooled to 25 ℃. And cutting, grinding and polishing the glass product, cleaning with deionized water and drying to obtain the glass product with the thickness of 0.5 mm.

The various properties of each glass article were measured and the results are shown in table 2. The test method comprises the following steps:

(1) glass Density is determined in g/cm according to ASTM C-693³。

(2) The coefficient of thermal expansion of the glass at 20-300 ℃ is measured in 10 units using a horizontal dilatometer with reference to ASTM E-228^-7/℃。

(3) The Young's modulus of the glass is measured in GPa according to ASTM C-623; the specific modulus is calculated from the ratio of Young's modulus and density, and the unit is GPa/g/cm³。

(4) Glass high temperature visco-temperature curve was determined using a rotary high temperature viscometer with reference to ASTM C-965, where 200P viscosity corresponds to temperature T₂₀₀In units of; 35000P viscosity temperature T₃₅₀₀₀In units of ℃.

(5) Determination of glass liquidus temperature T Using the ladder furnace method with reference to ASTM C-829_LIn units of; combining the high-temperature viscosity parameter to calculate and obtain the liquidus viscosity eta of the glass_LUnits are characterized in kilopoise (1000P).

(6) Determination of glass Strain Point temperature T Using an annealing Point Strain Point tester with reference to ASTM C-336_stIn units of; annealing point temperature T_aIn units of ℃.

(7) The transmittance of the glass is measured by using an ultraviolet-visible spectrophotometer, the thickness of the glass sample is 0.5mm, and the transmittance at 308nm is respectively taken, wherein the unit is percent.

(8) The hydrofluoric acid etching rate refers to the weight loss of an alkali-free glass substrate in a 10 wt% HF solution at 20 deg.C for 20min, and is denoted as CHF, in mg/cm²。

(9) The stress test refers to the stress distribution measurement of the glass using the birefringence (stress) measurement system EXICOR-GEN6 from Hinds instruments. Wherein, the length and the width of the glass sample are both more than or equal to 30mm, and the thickness of the glass plate is more than or equal to 0.1 mm. The distance between the measuring points is less than or equal to 10 mm.

Wherein, samples with length and width dimensions of more than or equal to 30mm prepared in examples 2, 7, 10, 1, 2 and 3 are subjected to stress test, and the maximum stress sigma of the corresponding glass samples is measured_maxA value and a STDEV value.

(10) Counting the number and the size of gaseous inclusions in the glass by using a polarization microscope (olympus, model BX51) multiplied by 200, converting the gaseous inclusions into an equivalent sphere on the basis of the equal volume if the gaseous inclusions are not spherical, calculating to obtain the equivalent spherical diameter (D.EQ.) in mm, and counting the gaseous inclusions with the equivalent spherical diameter (D.EQ.) larger than 0.02mm in unit/kg of the glass.

(11) And (3) detecting the content of chlorine: the content of chlorine element in the prepared alkali-free glass is measured by a fluorescence spectrometer, and the unit is weight percent.

TABLE 1

TABLE 2

The test results in table 2 show that: examples 1-16 of the present disclosure provide alkali-free glasses that simultaneously possess superior properties of higher strain point, higher young's modulus, higher chemical stability, higher glass formation stability, lower melting temperature, and lower liquidus temperature. Specifically, the density of the alkali-free glasses of examples 1-16 was less than 2.65g/cm³Heat in the range of 20-300 deg.CExpansion coefficient less than 40 x 10^-7V DEG C, Young's modulus of more than 82GPa, strain point temperature T_stAt a temperature of 750 ℃ or more and an annealing point temperature T_aIs above 800 ℃; liquidus temperature T_LBelow 1200 ℃; liquidus viscosity η_LIs more than 350 kpoise; a temperature T corresponding to a viscosity of 200 poise₂₀₀Is below 1680 ℃; temperature T corresponding to viscosity of 35000 poise₃₅₀₀₀Below 1330 ℃; transmittance at wavelength of 308nm is above 70%; the corrosion rate of the hydrofluoric acid CHF is 7.0mg/cm²The following; stress test maximum stress sigma_maxIs below 110 psi; a standard deviation of the stress test STDEV of 30psi or less; the content of gaseous inclusions with the equivalent spherical diameter (D.EQ.) larger than 0.02mm is less than 0.5 inclusions/Kg of glass; while only a portion of the properties of the glass samples provided in comparative examples 1-4 can reach the performance levels of the alkali-free glasses provided in examples 1-16 of the present disclosure, the alkali-free glasses provided in examples 1-16 of the present disclosure perform better than the products of comparative examples 1-4.

As can be seen from Table 2, comparing the data of examples 1-5 with the data of the remaining examples, the alkali-free glass compositions of the present disclosure include 59-62 wt% SiO₂19-20% by weight of Al₂O₃1.8-3 wt% of MgO, 4.5-6 wt% of CaO, 0.3-1.2 wt% of SrO, 9.5-12 wt% of BaO, 0.5-1 wt% of ZnO, 0.21-0.27 wt% of SnO₂And 0.1 to 1.0 wt.% NH₄Cl and the contents of the components are such that in the case where the A value calculated from the formulae (1) to (2) is from 7.4 to 7.64 and the B value is from 13 to 16.5, the alkali-free glasses produced from these alkali-free glass compositions have more excellent properties, the density, the thermal expansion coefficient, and the T of the alkali-free glasses₂₀₀、T₃₅₀₀₀、T_L、CHF、σ_maxSTDEV, and gaseous inclusions with an equivalent spherical diameter (D.EQ.) greater than 0.02mm, with lower Young's modulus, T_st、T_a、η_LAnd a higher transmittance at a wavelength of 308 nm.

The preferred embodiments of the present disclosure have been described in detail above, however, the present disclosure is not limited to the specific details of the above embodiments, and various simple modifications may be made to the technical solution of the present disclosure within the technical idea of the present disclosure, and these simple modifications all fall within the protection scope of the present disclosure.

It should be noted that the various features described in the above embodiments may be combined in any suitable manner without departing from the scope of the invention. In order to avoid unnecessary repetition, various possible combinations will not be separately described in this disclosure.

In addition, any combination of various embodiments of the present disclosure may be made, and the same should be considered as the disclosure of the present disclosure, as long as it does not depart from the spirit of the present disclosure.