Alkali-free boroaluminosilicate glass having good thermal stability and high crystallization margin, and preparation method therefor

Abstract

The present invention relates to the technical field of electronic glass, and specifically relates to an alkali-free boroaluminosilicate glass having good thermal stability and a high crystallization margin, and a preparation method therefor. The alkali-free boroaluminosilicate glass having good thermal stability and a high crystallization margin comprises, in mole percent, the following raw materials: 68.54%–72.82% SiO2, 11.84%–13.5% Al2O3, ≤ 2.23% B2O3, 4.72%–6.6% MgO, 4.65%–5.8% CaO, 0.8%–1.5% SrO, 3.2%–3.79% BaO, and 0.1% SnO2, where SiO2 + Al2O3 is 81.63%–84.66%, and (MgO + CaO + SrO + BaO) / Al2O3 is 1.15-1.30. The alkali-free boroaluminosilicate glass obtained in the present application has a high strain point and a high crystallization margin, and achieves both high thermal stability and high devitrification resistance.

Description

Heat-resistant and stable high-crystallization-margin alkali-free boro-aluminosilicate glass and preparation method thereof TECHNICAL FIELD

[0001] The present application relates to the technical field of electronic glass, in particular to heat-resistant and stable high-crystallization-margin alkali-free boro-aluminosilicate glass and preparation method thereof. BACKGROUND

[0002] With the continuous development of display technology, people's demand for display devices gradually tends to large size, high resolution and high-definition screen. Compared with amorphous silicon thin film transistor display, polycrystalline silicon thin film transistor can transmit electrons faster and more effectively, and has higher electron mobility, so polycrystalline silicon can manufacture smaller and faster transistors, and ultimately produce brighter and faster displays. However, for polycrystalline silicon transistors, the substrate is heated to 450-600℃ during processing, which is a higher processing temperature than the 350℃ peak temperature used to manufacture amorphous silicon transistors. At such a temperature, the substrate glass is very easy to deform, and the heat resistance of the substrate glass can be improved by adjusting the composition of the substrate glass and the forming process, which is mainly because high heat-resistant glass (high strain point) can prevent deformation due to poor heat resistance of the glass during heat treatment in the panel manufacturing process.

[0003] At the same time, the entire production process of polycrystalline silicon substrate glass needs to be carried out at a higher temperature, and the production process temperature of the substrate glass is high. In the melting process, the materials in the furnace are more likely to erode the refractory materials in the production line, resulting in more internal stone defects in the glass, and high forming temperature will cause the creep of overflow bricks to intensify, seriously affecting the service life of the production line and increasing the production cost. At the same time, the liquidus temperature of the substrate glass is related to the forming production of the substrate glass and the product quality of the substrate glass. Only by controlling the liquidus temperature of the substrate glass below a certain temperature and expanding the difference between the forming temperature and the liquidus temperature (crystallization margin) can the normal forming production be ensured. The liquidus temperature of the substrate glass is related to the glass composition, glass structure and glass phase separation, etc. By testing the production process and liquidus temperature of different material sides, the material side can be optimized. Therefore, accurate testing of the melting temperature, forming temperature and liquidus temperature of different material sides of the substrate glass has certain practical significance for the formulation of liquid crystal substrate glass production process, the stability of forming process and the control of product quality.

[0004] The currently disclosed substrate glass has high crystallization margin and liquidus viscosity, which significantly reduces the risk of cold devitrification of the substrate glass in the forming equipment, but the heat resistance and stability of the substrate glass and the devitrification resistance are still insufficient, and high heat resistance and stability and devitrification resistance cannot be considered at the same time. SUMMARY

[0005] The application aims to provide an alkali-free boro-aluminosilicate glass with high crystallization margin and heat resistance, and solve the problem that the alkali-free boro-aluminosilicate glass in the prior art cannot simultaneously have high heat resistance and high resistance to devitrification.

[0006] The application also provides a preparation method of the alkali-free boro-aluminosilicate glass with high crystallization margin and heat resistance, and solves the problem that the alkali-free boro-aluminosilicate glass in the prior art cannot simultaneously have high heat resistance and high resistance to devitrification.

[0007] To solve the above problems, the application provides an alkali-free boro-aluminosilicate glass with high crystallization margin and heat resistance, and the technical scheme is as follows:

[0008] The alkali-free boro-aluminosilicate glass with high crystallization margin and heat resistance comprises the following raw materials in terms of mole percentage: 68.54-72.82% of SiO2, 11.84-13.5% of Al2O3, ≤2.23% of B2O3, 4.72-6.6% of MgO, 4.65-5.8% of CaO, 0.8-1.5% of SrO, 3.2-3.79% of BaO, and 0.1% of SnO2, wherein SiO2+Al2O3 is 81.63-84.66%, and (MgO+CaO+SrO+BaO) / Al2O3 is 1.15-1.30.

[0009] The beneficial effects of the present application are: SiO2 is a network former in glass, and the molar percentage of SiO2 is designed to be 68.54% to 72.82%, which is beneficial to reduce the thermal expansion coefficient of the alkali-free boro-alumino-silicate glass, improve the thermal stability, chemical stability, softening point, strain point, heat resistance, hardness, mechanical strength and other properties of the alkali-free boro-alumino-silicate glass; the molar percentage of Al2O3 is designed to be 11.84% to 13.5%, which is used to increase the stability of the alkali-free boro-alumino-silicate glass, reduce the thermal expansion coefficient and increase the hardness of the glass; the molar percentage of B2O3 is designed to be ≤2.23%, which is used to improve the viscosity of the alkali-free boro-alumino-silicate glass and reduce the liquidus temperature; the molar percentage of MgO is designed to be 4.72% to 6.6%, which is used to reduce the high-temperature viscosity of the alkali-free boro-alumino-silicate glass and improve the melting performance of the alkali-free boro-alumino-silicate glass; the molar percentage of CaO is designed to be 4.65% to 5.8%, which is also used to reduce the high-temperature viscosity of the alkali-free boro-alumino-silicate glass and significantly improve the melting performance of the alkali-free boro-alumino-silicate glass; the molar percentage of SrO is designed to be 0.8% to 1.5%, which is used to suppress the rise of the liquidus temperature of the alkali-free boro-alumino-silicate glass; the molar percentage of BaO is designed to be 3.2% to 3.79%, which is beneficial to reduce the liquidus temperature of the alkali-free boro-alumino-silicate glass; the molar percentage of SnO2 as a fining agent is designed to be 0.1%, which can promote the elimination or dissolution and absorption of bubbles in the molten alkali-free boro-alumino-silicate glass; wherein the molar percentage of SiO2+Al2O3 is designed to be 81.63% to 84.66%, which is beneficial to improve the strain point of the alkali-free boro-alumino-silicate glass; the design of (MgO+CaO+SrO+BaO) / Al2O3 is 1.15 to 1.30, so that the alkali-free boro-alumino-silicate glass has high specific modulus and high strain point at the same time, thereby improving the resistance to devitrification.

[0010] The alkali-free boro-alumino-silicate glass provided by the present application has high heat resistance and high crystallization margin, and through the control of components and molar percentages, the strain point of the alkali-free boro-alumino-silicate glass is improved, and the deformation amount thereof in the panel processing and manufacturing process is reduced; at the same time, the crystallization margin of the alkali-free boro-alumino-silicate glass in the overflow forming down-draw process is improved, the crystallization defect rate is reduced, the production line life is prolonged, the production cost of the glass is reduced, and the alkali-free boro-alumino-silicate glass with high heat resistance and high crystallization margin has high heat resistance and high resistance to devitrification at the same time.

[0011] To further improve the strain point, liquidus viscosity and crystallization margin of the glass, preferably, the raw materials thereof include, in terms of mole percent: 69.12% to 72.82% SiO2, 11.84% to 13.1% Al2O3, ≤2.23% B2O3, 5.28% to 6.59% MgO, 4.65% to 5.78% CaO, 0.8% to 1.5% SrO, 3.2% to 3.79% BaO, and 0.1% SnO2, wherein SiO2+Al2O3 is 81.63% to 84.66%, and (MgO+CaO+SrO+BaO) / Al2O3 is 1.15 to 1.30.

[0012] To further improve the strain point, liquidus viscosity and crystallization margin of the glass, preferably, the raw materials thereof include, in terms of mole percent: 69.33% to 72.82% SiO2, 11.84% to 13.1% Al2O3, ≤2.23% B2O3, 5.28% to 6.59% MgO, 4.65% to 5.52% CaO, 0.8% to 1.5% SrO, 3.2% to 3.79% BaO, and 0.1% SnO2, wherein SiO2+Al2O3 is 81.63% to 84.66%, and (MgO+CaO+SrO+BaO) / Al2O3 is 1.15 to 1.30.

[0013] To further improve the strain point, liquidus viscosity and crystallization margin of the glass, preferably, the raw materials thereof include, in terms of mole percent: 70.5% to 72.82% SiO2, 11.84% to 13.1% Al2O3, ≤1.23% B2O3, 5.28% to 6.29% MgO, 4.99% to 5.01% CaO, 0.8% to 1.1% SrO, 3.54% to 3.79% BaO, and 0.1% SnO2, wherein SiO2+Al2O3 is 83% to 84.66%, and (MgO+CaO+SrO+BaO) / Al2O3 is 1.15 to 1.29.

[0014] To further improve the strain point, liquidus viscosity and crystallization margin of the glass, preferably, the raw materials thereof include, in terms of mole percent: 72.82% SiO2, 11.84% Al2O3, 5.28% MgO, 5.32% CaO, 1.1% SrO, 3.54% BaO, and 0.1% SnO2, wherein SiO2+Al2O3 is 84.66%, and (MgO+CaO+SrO+BaO) / Al2O3 is 1.29.

[0015] In order to make the glass have high heat resistance stability in the processing process, preferably, the strain point temperature of the heat-resistant high-crystallization-margin alkali-free boro-aluminosilicate glass is above 735℃. The glass with high strain point temperature above 735℃ can inhibit the thermal deformation of the glass plate in the manufacture of the polysilicon transistor display, thereby improving the yield of the display manufacture.

[0016] In order to make the glass have high resistance to devitrification in the overflow down-draw forming process, preferably, the liquidus viscosity of the heat-resistant high-crystallization-margin alkali-free boro-aluminosilicate glass is above 203426P, and the crystallization margin is above 80℃. The liquidus viscosity is greater than 20 million poise, the forming performance is excellent, the glass plate can be easily formed by the overflow down-draw method, the surface quality of the glass plate can be improved, and the manufacturing cost of the glass plate is reduced.

[0017] Preferably, the strain point temperature of the alkali-free boro-aluminosilicate glass is 736-754.1℃, the liquidus viscosity is 211706.6-357812P, and the crystallization margin is 81.1-107.1℃.

[0018] Preferably, the strain point temperature of the alkali-free boro-aluminosilicate glass is 736-754.1℃, the liquidus viscosity is 211706.6-357812P, and the crystallization margin is 81.1-107.1℃.

[0019] Preferably, the strain point temperature of the alkali-free boro-aluminosilicate glass is 736-754.1℃, the liquidus viscosity is 211706.6-357812P, and the crystallization margin is 81.1-107.1℃.

[0020] Preferably, the strain point temperature of the alkali-free boro-aluminosilicate glass is 736-754.1℃, the liquidus viscosity is 211706.6-357812P, and the crystallization margin is 81.1-107.1℃.

[0021] The application also provides a preparation method of the heat-resistant high-crystallization-margin alkali-free boro-aluminosilicate glass.

[0022] The preparation method of the heat-resistant high-crystallization-margin alkali-free boro-aluminosilicate glass comprises the following steps: mixing the raw materials in sequence, melting, and clarifying to obtain a clarified glass melt, and then forming the clarified glass melt by the overflow down-draw method to obtain the heat-resistant high-crystallization-margin alkali-free boro-aluminosilicate glass.

[0023] The application has the advantages that the preparation method is stable in the forming process, the quality of the alkali-free boro-aluminosilicate glass product is controlled, the glass has a high strain point, the preparation method is safe, convenient to operate, and low in cost.

[0024] In order to make the glass melt completely and uniformly, preferably, the melting temperature is 1590-1630 DEG C.

[0025] In order to make the glass melt completely and uniformly, preferably, the melting temperature is 1590-1630 DEG C. DETAILED DESCRIPTION

[0026] The prior art alkali-free boro-aluminosilicate glass cannot simultaneously have high heat-resistant stability and resistance to devitrification. The present application provides an alkali-free boro-aluminosilicate glass with high heat-resistant stability and high crystallization margin, which comprises, in terms of mole percentage, 68.54-72.82% SiO2, 11.84-13.5% Al2O3, ≤2.23% B2O3, 4.72-6.6% MgO, 4.65-5.8% CaO, 0.8-1.5% SrO, 3.2-3.79% BaO and 0.1% SnO2, wherein SiO2+Al2O3 is 81.63-84.66% and (MgO+CaO+SrO+BaO) / Al2O3 is 1.15-1.30.

[0027] The technical concept of the present application is that, in the alkali-free boro-aluminosilicate glass with high heat-resistant stability and high crystallization margin, SiO2 is the network former in the glass, which forms an irregular continuous network in the structure of silicon-oxygen tetrahedron [SiO4] to form the glass framework, thereby reducing the thermal expansion coefficient of the glass and improving the heat stability, chemical stability, softening point, strain point, heat resistance, hardness, mechanical strength and other properties of the glass. If the mole percentage of SiO2 is lower than 68.54%, it is difficult to improve the strain point, and the density will also become too high. If the mole percentage of SiO2 is higher than 72.82%, in addition to the high-temperature viscosity being increased and the melting property being decreased, devitrification crystals are more likely to appear, and the liquidus temperature is increased. Therefore, in the present application, the mole percentage of SiO2 is 68.54-72.82%.

[0028] Al2O3 is the network former oxide. When there is insufficient oxygen atom in the glass, the coordination state of aluminum is aluminum-oxygen octahedron [AlO6] in the network gap. When there is excess oxygen atom in the glass, the coordination state of aluminum is aluminum-oxygen tetrahedron [AlO4] in the glass structure, which plays a role of network supplement, increases the stability of the glass, reduces the thermal expansion coefficient, increases the hardness of the glass, and increases the mole percentage of Al2O3 to improve the strain point temperature and elastic modulus of the glass. However, if the mole percentage of Al2O3 is higher than 13.5%, mullite and anorthite devitrification crystals are more likely to appear, and the liquidus temperature is increased. Therefore, in the present application, the mole percentage of Al2O3 is 11.84-13.5%.

[0029] B2O3 in the glass mainly at high temperature can reduce the viscosity of the glass, play a role in flux, and at low temperature can increase the viscosity of the glass, reduce the liquidus temperature. But its content is too much will make the glass expansion coefficient increases, the strain point temperature decreases, the elastic modulus decreases. Therefore, its mole percentage ≤2.23%. If the mole percentage is higher than 2.23%, the strain point of the glass will decrease significantly, resulting in a large thermal deformation during processing of the display. Therefore, the mole percentage of B2O3 in the present application is ≤2.23%.

[0030] MgO is used to reduce the high temperature viscosity and improve the melting performance of the glass. If the content of MgO is too high, the strain point will decrease significantly, and the liquidus temperature will increase, so that the resistance to devitrification is poor, which is not conducive to the forming process of overflow down-draw method. Therefore, the mole percentage of MgO in the present application is 4.72% to 6.6%.

[0031] CaO is a component that does not decrease the strain point but reduces the high temperature viscosity and significantly improves the melting performance. But if the content of CaO is too much, the glass is easy to devitrify, and the thermal expansion coefficient will be too high. Therefore, the mole percentage of CaO in the present application is 4.65% to 5.8%.

[0032] SrO and CaO are components that do not decrease the strain point but reduce the high temperature viscosity and significantly improve the melting performance. At the same time, SrO is also a component that inhibits phase separation and improves the resistance to devitrification, so it is also a component that inhibits the increase of the liquidus temperature. If the content of SrO is too low, it is difficult to inhibit phase separation and improve the resistance to devitrification, but if the content is too high, it is easy to appear strontium silicate series devitrification crystal, which reduces the resistance to devitrification. Therefore, the mole percentage of SrO in the present application is 0.8% to 1.5%.

[0033] Compared with SrO, BaO is a component that significantly improves the resistance to devitrification, which is beneficial to reduce the liquidus temperature of the glass. However, if BaO replaces other alkaline earth metal oxides or the content of BaO is too high, the melting temperature will increase, the high temperature viscosity will increase, and the melting performance will decrease. At the same time, as a divalent network external oxide, BaO is more serious in the erosion of refractory materials. Based on the environmental protection and light and thin development trend of the substrate glass, the addition amount of BaO must be controlled. Therefore, the mole percentage of BaO in the present application is 3.2% to 3.79%.

[0034] SnO2 is added to the base glass component as a fining agent, which can promote the elimination or dissolution and absorption of bubbles in the glass melting liquid. The mole percentage of SnO2 is designed to be 0.1%, which can promote the elimination or dissolution and absorption of bubbles in the glass melting liquid.

[0035] SiO2 and Al2O3 are both network forming oxide, both of which can increase the strain point, but when the content of SiO2 is too high, it is easy to precipitate cristobalite and other devitrification crystals; when the content of Al2O3 is too high, it is easy to precipitate mullite, anorthite and other alkaline earth metal aluminosilicate devitrification crystals. Therefore, the molar percentage of SiO2+Al2O3 in the present application is 81.63% to 84.66%.

[0036] RO represents alkaline earth metal oxide, which includes MgO, CaO, SrO and BaO in the present application. The ratio of the sum of the molar amount of alkaline earth metal oxide (MgO+CaO+SrO+BaO) to the molar amount of Al2O3 is designed to form new compounds with silicate in the glass, thereby reducing the melting point of the glass and improving the chemical stability of the glass. This ratio takes into account both high specific modulus and high strain point, thereby improving the devitrification resistance. However, if the ratio is too small, devitrification crystals may be caused by alkaline earth metal, and if the ratio is too large, devitrification crystals of anorthite and other alkaline earth metal aluminosilicate may be caused. Therefore, the ratio of (MgO+CaO+SrO+BaO) / Al2O3 in the present application is 1.15 to 1.30, so that the glass has high thermal stability, large crystallization margin (difference between forming temperature and liquidus temperature), and higher liquidus viscosity, which is beneficial to the stability of the overflow downdraw forming process.

[0037] The alkali-free boro-aluminosilicate glass with high crystallization margin and thermal stability provided by the present application has a high strain point, a small deformation amount in the panel processing and manufacturing process, a high crystallization margin in the overflow downdraw forming process, a low crystallization defect rate, a long production line life and a low glass production cost. The strain point temperature of the alkali-free boro-aluminosilicate glass with high crystallization margin and thermal stability is above 735.2℃, the liquidus viscosity is above 203426.2P, and the crystallization margin is above 80.2℃.

[0038] Specifically, the preparation method of the alkali-free boro-aluminosilicate glass with high crystallization margin and thermal stability comprises the following steps:

[0039] (1) The raw materials are weighed according to the molar percentage content, and the corresponding raw materials of each component are poured into a mixer to mix uniformly to obtain a mixture;

[0040] (2) The mixture is put into a glass kiln, heated and melted in the glass kiln to form a glass melt, and then the glass melt is flowed into a platinum channel for clarification to obtain a clarified glass melt;

[0041] (3) using overflow down-draw forming process to form the clarified glass melt to obtain sheet glass, that is, the heat-resistant and stable high-crystallization margin alkali-free boro-aluminosilicate glass.

[0042] Preferably, in step (2), the melting temperature is 1590-1630℃.

[0043] Preferably, in step (3), the forming temperature is 1270-1300℃, which is the temperature in the overflow down-draw forming process in the process of preparing the glass.

[0044] The implementation process of the present application will be described in detail below in combination with specific examples.

[0045] In the following examples and comparative examples, the raw materials used are all ordinary commercially available products that can be directly purchased or prepared according to conventional techniques in the art.

[0046] I. Examples of the method for preparing the heat-resistant and stable high-crystallization margin alkali-free boro-aluminosilicate glass according to the present application

[0047] Examples 1-20

[0048] Examples 1-20 all provide heat-resistant and stable high-crystallization margin alkali-free boro-aluminosilicate glass; wherein the method for preparing the heat-resistant and stable high-crystallization margin alkali-free boro-aluminosilicate glass comprises the following steps:

[0049] (1) according to the allocation ratio of each component in Table 1 and Table 2, calculate and weigh the corresponding raw materials of each component, pour the raw materials of each component into a mixer, and mix uniformly to obtain a mixture;

[0050] (2) put the mixture into a glass kiln, heat and melt in the glass kiln to form a glass melt, then flow the glass melt into a platinum channel for clarification to obtain a clarified glass melt, wherein the melting temperature is 1600℃;

[0051] (3) using overflow down-draw forming process to form the clarified glass melt to obtain sheet glass, that is, the heat-resistant and stable high-crystallization margin alkali-free boro-aluminosilicate glass, wherein the forming temperature is 1280℃.

[0052] In the present application, when the melting temperature is 1590℃ or 1630℃, the heat-resistant and stable high-crystallization margin alkali-free boro-aluminosilicate glass prepared thereby achieves the same technical effect as the above examples.

[0053] In the present application, when the forming temperature is 1270℃ or 1300℃, the heat-resistant and stable high-crystallization margin alkali-free boro-aluminosilicate glass prepared thereby achieves the same technical effect as the above examples.

[0054] Table 1. Component proportions of the alkali-free boro-aluminosilicate glasses of Examples 1-10

[0055] Table 2. Component proportions of the alkali-free boro-aluminosilicate glasses of Examples 11-20

[0056] II. Experimental Examples

[0057] The strain point temperature, forming temperature, liquidus temperature, liquidus viscosity and crystallization margin of the heat-resistant and stable high-crystallization-margin alkali-free boro-aluminosilicate glasses prepared in Examples 1-20 were tested and calculated. Specifically, the strain point temperature was tested by the standard method of ASTM C336, i.e. the glass was drawn into a glass filament as required in the standard, and the strain point temperature was detected in a special device; the liquidus viscosity was tested by first testing the viscosity-temperature curve of the glass, i.e. the glass particles of 10-30 mesh sieved from the broken glass sheet of Examples 1-20 were put into a corresponding container, the glass was melted into a glass liquid by heating, the spindle was then lowered and rotated at different speeds, and the torque at different speeds was read by a corresponding software, so as to calculate the viscosity of the molten glass at different temperatures, and finally the corresponding liquidus viscosity was calculated according to the viscosity-temperature curve obtained by the viscosity test; the forming temperature was the temperature corresponding to the viscosity on the viscosity-temperature curve obtained above; the liquidus temperature was obtained by crushing the glass particles of 10-30 mesh sieved from the glass sheet of Examples 1-20, putting them into a long container, and placing them in a furnace with a temperature gradient at a certain temperature for 24 hours, then taking them out and observing the position of the initial crystallization under a microscope after cooling, and calculating the corresponding temperature value; the crystallization margin was the difference between the forming temperature and the liquidus temperature. The specific test results are shown in Tables 3 and 4:

[0058] Table 3. Performance test results of the alkali-free boro-aluminosilicate glasses prepared in Examples 1-10

[0059] Table 4. Performance test results of the alkali-free boro-aluminosilicate glasses prepared in Examples 11-20

[0060] As can be seen from Table 3 and Table 4, the strain point temperature of the heat-resistant and stable high-crystallization-marginality alkali-free boro-aluminosilicate glass according to the present application is above 735.2℃, and can be as high as 754.1℃, the liquidus viscosity is above 203426.2P, and can be as high as 357812P, and the crystallization margin is above 80.2℃, and can be as high as 107.1℃. In Example 6, the strain point temperature, the liquidus viscosity and the crystallization margin of the heat-resistant and stable high-crystallization-marginality alkali-free boro-aluminosilicate glass are the highest. Thus, the heat-resistant and stable high-crystallization-marginality alkali-free boro-aluminosilicate glass according to the present application has a high strain point by controlling the molar percentage range of each raw material, reduces the deformation amount during the panel processing and manufacturing process, and improves the heat-resistant temperature. Meanwhile, the crystallization margin and the liquidus viscosity of the alkali-free boro-aluminosilicate glass during the overflow forming down-draw process are improved, the crystallization defect rate is reduced, the devitrification resistance is improved, the production line life is prolonged, and the glass production cost is reduced. The heat-resistant and stable high-crystallization-marginality alkali-free boro-aluminosilicate glass according to the present application has both high heat-resistant stability and high devitrification resistance.

[0061] The preferred embodiments of the present application have been described above with the preferred embodiments; however, the present application is not limited to the above examples. It will be appreciated by those skilled in the art that the present application can be variously changed and modified. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall fall within the scope of the present application.

Claims

1. A heat resistant, stable, high crystallization margin, alkali-free boro-aluminosilicate glass, characterized in that, The raw materials thereof include, in terms of mole percent: 68.54% to 72.82% SiO2, 11.84% to 13.5% Al2O3, ≤2.23% B2O3, 4.72% to 6.6% MgO, 4.65% to 5.8% CaO, 0.8% to 1.5% SrO, 3.2% to 3.79% BaO, and 0.1% SnO2, wherein SiO2+Al2O3 is 81.63% to 84.66%, and (MgO+CaO+SrO+BaO) / Al2O3 is 1.15 to 1.

30.

2. The heat resistant, stable high devitrification margin, alkali-free boro-aluminosilicate glass according to claim 1, wherein, The raw materials thereof include, in terms of mole percent: 69.12% to 72.82% SiO2, 11.84% to 13.1% Al2O3, ≤2.23% B2O3, 5.28% to 6.59% MgO, 4.65% to 5.78% CaO, 0.8% to 1.5% SrO, 3.2% to 3.79% BaO, and 0.1% SnO2, wherein SiO2+Al2O3 is 81.63% to 84.66%, and (MgO+CaO+SrO+BaO) / Al2O3 is 1.15 to 1.

30.

3. The heat resistant, stable high devitrification margin, alkali-free boro-aluminosilicate glass according to claim 1, wherein, The raw materials thereof include, in terms of mole percent: 69.33% to 72.82% SiO2, 11.84% to 13.1% Al2O3, ≤2.23% B2O3, 5.28% to 6.59% MgO, 4.65% to 5.52% CaO, 0.8% to 1.5% SrO, 3.2% to 3.79% BaO, and 0.1% SnO2, wherein SiO2+Al2O3 is 81.63% to 84.66%, and (MgO+CaO+SrO+BaO) / Al2O3 is 1.15 to 1.

30.

4. The heat resistant, stable high devitrification margin, alkali-free boro-aluminosilicate glass according to claim 1, wherein, The raw materials thereof include, in terms of mole percent: 70.5% to 72.82% SiO2, 11.84% to 13.1% Al2O3, ≤1.23% B2O3, 5.28% to 6.29% MgO, 4.99% to 5.01% CaO, 0.8% to 1.1% SrO, 3.54% to 3.79% BaO, and 0.1% SnO2, wherein SiO2+Al2O3 is 83% to 84.66%, and (MgO+CaO+SrO+BaO) / Al2O3 is 1.15 to 1.

29.

5. The heat resistant, stable high devitrification margin, alkali-free boro-aluminosilicate glass according to claim 1, wherein, The raw materials thereof include, in terms of mole percent: 72.82% SiO2, 11.84% Al2O3, 5.28% MgO, 5.32% CaO, 1.1% SrO, 3.54% BaO, and 0.1% SnO2, wherein SiO2+Al2O3 is 84.66%, and (MgO+CaO+SrO+BaO) / Al2O3 is 1.

29.

6. The heat resistant, stable high devitrification margin, alkali-free boro-aluminosilicate glass according to any one of claims 1, wherein, The strain point temperature of the heat-resistant and stable high-crystallization-margin alkali-free boro-aluminosilicate glass is above 735℃.

7. The heat resistant, stable high devitrification margin, alkali-free boro-aluminosilicate glass according to any one of claims 1, wherein, The liquidus viscosity of the heat-resistant and stable high-crystallization-margin alkali-free boro-aluminosilicate glass is above 203426 P, and the crystallization margin is above 80℃.

8. A method of producing the heat resistant, stable high-crystallization margin, alkali-free boro-aluminosilicate glass according to any one of claims 1 to 7, characterized by, The method comprises the following steps: mixing the raw materials, melting, clarifying to obtain a clarified glass melt, and then using an overflow down-draw method to shape the clarified glass melt to obtain an alkali-free boro-aluminosilicate glass with high heat-resistant stability and high crystallization margin.

9. The method of making a heat resistant, stable high devitrification margin, alkali-free boro-aluminosilicate glass according to claim 8, wherein, The melting temperature is 1590-1630 DEG C.

10. The method of making a heat resistant, stable high devitrification margin, alkali-free boro-aluminosilicate glass according to claim 8, wherein, The shaping temperature is 1270-1300 DEG C.

Images