LITHIUM-ZIRCONIUM-BASED ALUMINOSILICATE GLASS, REINFORCED GLASS, PREPARATION METHOD THEREFOR AND DISPLAY DEVICE

Abstract

Disclosed is a lithium zirconium-based aluminosilicate glass, comprising the following components by mass percentage: 50%-72% of SiO.sub.2, 10%-27% of Al.sub.2O.sub.3, 0.1%-10.0% of B.sub.2O.sub.3, 2%-10% of Li.sub.2O, 4%-15% of Na.sub.2O, 0.1%-5.0% of ZrO.sub.2, and 0-4% of K.sub.2O, wherein the total mass percentage of Li.sub.2O, Na.sub.2O and K.sub.2O is ≥9%, and the ratio of the mass of Li.sub.2O to the total mass of Li.sub.2O, Na.sub.2O and K.sub.2O is (0.22-0.48):1.

Claims

1. A lithium-zirconium-based aluminosilicate glass comprising the following components by mass percentage: 50%˜72% of SiO.sub.2; 10%˜27% of Al.sub.2O.sub.3; 0.1%˜10.0% of B.sub.2O.sub.3; 2%˜10% of Li.sub.2O; 4%˜15% of Na.sub.2O; 0.1%˜5.0% of ZrO.sub.2; and 0˜4% of K.sub.2O, wherein a total mass percentage of Li.sub.2O, Na.sub.2O, and K.sub.2O is no less than 9%, and a ratio of a mass of Li.sub.2O to a total mass of Li.sub.2O, Na.sub.2O, and K.sub.2O is (0.22˜0.48):1.

2. The lithium-zirconium-based aluminosilicate glass of claim 1, wherein a total mass percentage of ZrO.sub.2 and Al.sub.2O.sub.3 is greater than 16%, and the ratio of the mass of Li.sub.2O to the total mass of Li.sub.2O, Na.sub.2O, and K.sub.2O is (0.27˜0.41):1.

3. The lithium-zirconium-based aluminosilicate glass of claim 2, wherein the total mass percentage of Li.sub.2O, Na.sub.2O, and K.sub.2O is no less than 12%, the total mass percentage of ZrO.sub.2 and Al.sub.2O.sub.3 is greater than 19.5%, and the ratio of the mass of Li.sub.2O to the total mass of Li.sub.2O, Na.sub.2O, and K.sub.2O is (0.29˜0.38):1.

4. The lithium-zirconium-based aluminosilicate glass of claim 1, wherein ZrO.sub.2 has a mass percentage of 1%˜4%, and Al.sub.2O.sub.3 has a mass percentage of 13%˜25%.

5. The lithium-zirconium-based aluminosilicate glass of claim 4, wherein ZrO.sub.2 has the mass percentage of 3%˜4%, and Al.sub.2O.sub.3 has the mass percentage of 16%˜22%.

6. The lithium-zirconium-based aluminosilicate glass of claim 1, wherein Li.sub.2O has a mass percentage of 3%˜7%, Na.sub.2O has a mass percentage of 6%˜12%, and K.sub.2O has a mass percentage of 0˜3%.

7. The lithium-zirconium-based aluminosilicate glass of claim 6, wherein Li.sub.2O has the mass percentage of 4%˜6%, Na.sub.2O has the mass percentage of 8%˜10%, and K.sub.2O has the mass percentage of 0˜2%.

8. The lithium-zirconium-based aluminosilicate glass of claim 1, wherein the lithium-zirconium-based aluminosilicate glass comprises by mass percentage: 55%˜67% of SiO.sub.2, 13%˜25% of Al.sub.2O.sub.3, 0.5%˜4% of B.sub.2O.sub.3, 3%˜7% of Li.sub.2O, 6%˜12% of Na.sub.2O, 1%˜4% of ZrO.sub.2, and 0˜3% of K.sub.2O, wherein a total mass percentage of ZrO.sub.2 and Al.sub.2O.sub.3 is greater than 16%, and the ratio of the mass of Li.sub.2O to the total mass of Li.sub.2O, Na.sub.2O, and K.sub.2O is (0.27˜0.41):1.

9. The lithium-zirconium-based aluminosilicate glass of claim 8, wherein the lithium-zirconium-based aluminosilicate glass comprises by mass percentage: 58%˜64% of SiO.sub.2, 16%˜22% of Al.sub.2O.sub.3, 1%˜2% of B.sub.2O.sub.3, 4%˜6% of Li.sub.2O, 8%˜10% of Na.sub.2O, 3%˜4% of ZrO.sub.2, and 0˜2% of K.sub.2O, wherein the total mass percentage of Li.sub.2O, Na.sub.2O, and K.sub.2O is no less than 12%, the total mass percentage of ZrO.sub.2 and Al.sub.2O.sub.3 is greater than 19.5%, and the ratio of the mass of Li.sub.2O to the total mass of Li.sub.2O, Na.sub.2O, and K.sub.2O is (0.29˜0.38):1.

10. The lithium-zirconium-based aluminosilicate glass of claim 1, wherein the lithium-zirconium-based aluminosilicate glass further comprises at least one of MgO with a mass percentage of no greater than 6%, CaO with a mass percentage of no greater than 4%, SrO with a mass percentage of no greater than 4%, ZnO with a mass percentage of no greater than 4%, and TiO.sub.2 with a mass percentage of no greater than 2%.

11. The lithium-zirconium-based aluminosilicate glass of claim 1, wherein the lithium-zirconium-based aluminosilicate glass further comprises at least one of MgO with a mass percentage of no greater than 4%, CaO with a mass percentage of no greater than 2%, SrO with a mass percentage of no greater than 2%, ZnO with a mass percentage of no greater than 2%, and TiO.sub.2 with a mass percentage of no greater than 1%.

12. The lithium-zirconium-based aluminosilicate glass of claim 1, wherein the lithium-zirconium-based aluminosilicate glass further comprises MgO with a mass percentage of no greater than 2%.

13. The lithium-zirconium-based aluminosilicate glass of claim 1, wherein the lithium-zirconium-based aluminosilicate glass further comprises at least one of SnO.sub.2 with a mass percentage of no greater than 1% and CeO.sub.2 with a mass percentage of no greater than 0.5%.

14. The lithium-zirconium-based aluminosilicate glass of claim 1, wherein the lithium-zirconium-based aluminosilicate glass further comprises at least one of MgO with a mass percentage of no greater than 4%, ZnO with a mass percentage of no greater than 2%, TiO.sub.2 with a mass percentage of no greater than 1%, SnO.sub.2 with a mass percentage of no greater than 0.5%, and CeO.sub.2 with a mass percentage of no greater than 0.5%.

15. A reinforced glass obtained from the lithium-zirconium-based aluminosilicate glass of claim 1 by chemical reinforcement.

16. The reinforced glass of claim 15, wherein the reinforced glass has a bending strength greater than 700 MPa, and a falling ball energy withstanding exceeding 0.4 J.

17. A method for preparing a reinforced glass comprising steps of: subjecting the lithium-zirconium-based aluminosilicate glass of claim 1 to a tempering treatment in a mixed melt of NaNO.sub.3 and KNO.sub.3 at a temperature of 390° C.˜420° C. and a mass ratio of 2:8˜8:2 for 2 h˜6 h, and then subjecting the lithium-zirconium-based aluminosilicate glass to a tempering treatment in a mixed melt of NaNO.sub.3 and KNO.sub.3 at a temperature of 380° C.˜400° C. and a mass ratio of 0.1:99.9˜15:85 for 2 h˜4 h to obtain the reinforced glass.

18. The method for preparing the reinforced glass of claim 17, wherein in the step of subjecting the lithium-zirconium-based aluminosilicate glass to a tempering treatment in a mixed melt of NaNO.sub.3 and KNO.sub.3 at a temperature of 390° C.˜420° C. and a mass ratio of 2:8˜8:2 for 2 h˜6 h, the mass ratio of NaNO.sub.3 and KNO.sub.3 in the mixed melt is 6:4˜4:6.

19. The method for preparing the reinforced glass of claim 17, wherein the temperature in the step of subjecting the lithium-zirconium-based aluminosilicate glass to a tempering treatment in a mixed melt of NaNO.sub.3 and KNO.sub.3 at a temperature of 390° C.˜420° C. and a mass ratio of 2:8˜8:2 for 2 h˜6 h is 10° C.˜20° C. higher than that in the step of subjecting the lithium-zirconium-based aluminosilicate glass to a tempering treatment in a mixed melt of NaNO.sub.3 and KNO.sub.3 at a temperature of 380° C.˜400° C. and a mass ratio of 0.1:99.9˜15:85 for 2 h˜4 h.

20. A display device comprising the lithium-zirconium-based aluminosilicate glass of claim 1.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0013] FIG. 1 is a process flow chart of a method for preparing a lithium-zirconium-based aluminosilicate glass according to an embodiment; and

[0014] FIG. 2 is a process flow chart of a method for preparing a reinforced glass according to an embodiment.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0015] In order to facilitate the understanding of the present disclosure, the present disclosure will be more fully described below with reference to specific embodiments. Preferable embodiments of the present disclosure are set forth in the specific embodiments. However, the present disclosure may be implemented in many different forms and is not limited to the examples described herein. Rather, these examples are provided for the purpose of giving a more thorough understanding of the present disclosure.

[0016] All technical and scientific terms used herein have the same meaning as commonly understood by skilled person in the art to which this disclosure belongs, unless otherwise defined.

[0017] The terms used in the specification of the present disclosure herein are for the purpose of describing specific embodiments only and are not intended to limit the present disclosure.

[0018] A lithium-zirconium-based aluminosilicate glass according to an embodiment includes the following components by mass percentage:

50%˜72% of SiO.SUB.2.;

[0019] 10%˜27% of Al.sub.2O.sub.3;
0.1%˜10.0% of B.sub.2O.sub.3;

2%˜10% of Li.SUB.2.O;

4%˜15% of Na.SUB.2.O;

0.1%˜5.0% of ZrO.SUB.2.; and

0˜4% of K.SUB.2.O,

[0020] wherein the total mass percentage of Li.sub.2O, Na.sub.2O, and K.sub.2O is no less than 9%, the total mass percentage of ZrO.sub.2 and Al.sub.2O.sub.3 is greater than 10%, and a ratio of the mass of Li.sub.2O to the total mass of Li.sub.2O, Na.sub.2O, and K.sub.2O is (0.22˜0.48):1.

[0021] In an embodiment, the lithium-zirconium-based aluminosilicate glass further includes at least one of MgO, CaO, SrO, ZnO, and TiO.sub.2. Specifically, MgO has a mass percentage of no greater than 6%, CaO has a mass percentage of no greater than 4%, SrO has a mass percentage of no greater than 4%, ZnO has a mass percentage of no greater than 4%, and TiO.sub.2 has a mass percentage of no greater than 2%.

[0022] Further, MgO has a mass percentage of no greater than 4%, CaO has a mass percentage of no greater than 2%, SrO has a mass percentage of no greater than 2%, ZnO has a mass percentage of no greater than 2%, and TiO.sub.2 has a mass percentage of no greater than 1%.

[0023] Furthermore, the lithium-zirconium-based aluminosilicate glass further includes at least one of MgO, ZnO, and TiO.sub.2, wherein MgO has a mass percentage of no greater than 2%, ZnO has a mass percentage of no greater than 2%, and TiO.sub.2 has a mass percentage of no greater than 1%.

[0024] In an embodiment, the lithium-zirconium-based aluminosilicate glass further includes no greater than 1% of SnO.sub.2 by mass percentage. Furthermore, SnO.sub.2 has a mass percentage of no greater than 0.5%.

[0025] In another embodiment, the lithium-zirconium-based aluminosilicate glass further includes no greater than 0.5% of CeO.sub.2 by mass percentage.

[0026] More preferably, the lithium-zirconium-based aluminosilicate glass includes: 50%˜72% of SiO.sub.2, 10%˜27% of Al.sub.2O.sub.3, 0.1%˜10.0% of B.sub.2O.sub.3, 2%˜10% of Li.sub.2O, 4%˜15% of Na.sub.2O, 0.1%˜5.0% of ZrO.sub.2, 0˜4% of K.sub.2O, MgO with a mass percentage of no greater than 4%, ZnO with a mass percentage of no greater than 2%, TiO.sub.2 with a mass percentage of no greater than 1%, SnO.sub.2 with a mass percentage of no greater than 1%, and CeO.sub.2 with a mass percentage of no greater than 0.5%. The total mass percentage of Li.sub.2O, Na.sub.2O, and K.sub.2O is no less than 9%, and the ratio of the mass of Li.sub.2O to the total mass of Li.sub.2O, Na.sub.2O, and K.sub.2O is (0.22˜0.48):1.

[0027] It should be noted that in this embodiment, P.sub.2O.sub.5 and Fe.sub.2O.sub.3 are not contained in the lithium-zirconium-based aluminosilicate glass. Without adding P.sub.2O.sub.5 to the lithium-zirconium-based aluminosilicate glass, the P-B phase separation opacification caused by the addition of P.sub.2O.sub.5 and B.sub.2O.sub.3 can be avoided, so as to avoid the increase in haze (i.e., opacity) and the reduction of the chemical stability of the glass.

[0028] SiO.sub.2 (silicon dioxide) is an important glass-forming oxide and an essential component to form a glass skeleton. SiO.sub.2 can improve the strength and chemical stability of the glass, and can make the glass obtain a higher strain point and a lower coefficient of thermal expansion. In this embodiment, SiO.sub.2 preferably has a mass percentage of 50%˜72%, more preferably, a mass percentage of 55%˜67%, and most preferably, a mass percentage of 58%˜64%. If SiO.sub.2 has a mass percentage of less than 50%, the main body network structure, the mechanical properties, and the weather resistance of the glass will become poor. If SiO.sub.2 has a mass percentage of greater than 72%, the melting temperature of the glass during the production process will be too high, the energy consumption will increase, and it will be easy to cause defects such as frequent bubbles and stones. In addition, the proportion of silica skeleton structure will be too high, and the network gap will be small, which will be not conducive to chemical reinforcement of ion exchange, thereby affecting the efficiency of chemical enhancement. Therefore, in this embodiment, SiO.sub.2 is set to have a mass percentage of 50%˜72%.

[0029] Al.sub.2O.sub.3 (aluminium sesquioxide) can participate in the formation of the network and act as a network generator, and can reduce the crystallization tendency of the glass, improve the chemical stability, thermal stability, mechanical strength, and hardness of the glass. In addition, Al.sub.2O.sub.3 is also an essential component to increase the elastic modulus of stretched glass. However, the addition of Al.sub.2O.sub.3 will increase the viscosity of the glass. If the mass percentage of Al.sub.2O.sub.3 is too high, it will be difficult to obtain glass with long material properties, making it difficult to mold the glass. Besides, Al.sup.3+ in the glass tends to form an aluminum-oxygen tetrahedral network [AlO.sub.4], which is much larger than the silicon-oxygen tetrahedral [SiO.sub.4] network, leaving larger voids as channels for ion diffusion. As a result, the high content of Al.sub.2O.sub.3 in the glass can promote the migration and replacement rate of alkali metal ions. The higher the content of Al.sub.2O.sub.3, the larger the gap in the skeleton network, which is more conducive to ion exchange. However, the coefficient of thermal expansion will not be further reduced due to its high content. On the contrary, the high temperature viscosity of the glass will increase significantly and the melting temperature during the production process will be too high and the energy consumption will increase, which is also not conducive to the control of defects such as bubbles and stones. However, if the content of Al.sub.2O.sub.3 is low, the voids in the network space will become smaller, which is not conducive to ion migration and seriously affects the efficiency of chemical enhancement. Therefore, in this embodiment, Al.sub.2O.sub.3 preferably has a mass percentage of 10%˜27%, more preferably, a mass percentage of 13%˜25%, and most preferably, a mass percentage of 16%˜22%.

[0030] B.sub.2O.sub.3 (boron oxide) is one of the important components of boro-aluminosilicate glass and belongs to a glass former oxide, which can reduce the coefficient of thermal expansion of the aluminosilicate glass and improve the thermal and chemical stabilities of the aluminosilicate glass. If the content of B.sub.2O.sub.3 is too high, it will cause serious boron volatilization at high temperature due to its effect of reducing viscosity. In addition, the forming temperature will be narrowed due to the too high content of B.sub.2O.sub.3, which will make it difficult to control the wall thickness and pipe diameter accuracy in the forming of boro-aluminosilicate glass. In addition, when the amount of B.sub.2O.sub.3 introduced is too high, the expansion coefficient of boro-aluminosilicate glass will increase due to the increase of boron-oxygen triangle [BO.sub.3], and an abnormal phenomenon will occur. When the content of B.sub.2O.sub.3 is too high, the ion exchange capacity of the glass will be significantly reduced. Therefore, in this embodiment, B.sub.2O.sub.3 preferably has a mass percentage of 0.1%˜10.0%, more preferably, a mass percentage of 0.5%˜4.0%, and most preferably, a mass percentage of 1%˜2%.

[0031] Li.sub.2O (lithium oxide) is an ideal flux and is the main component for ion exchange. Due to the polarization characteristics of Li.sup.+, Li.sub.2O can effectively reduce high-temperature viscosity at high temperature, and since Li.sup.+ has a small radius, Li.sub.2O can be filled in the glass body air to balance free oxygen. Thus, a proper amount of Li.sub.2O can significantly enhance the mechanical strength, surface hardness, and chemical resistance of the glass body. Since in this embodiment, the mixed molten salt of NaNO.sub.3 and KNO.sub.3 is used in the reinforcement process, the depth of the compressive stress layer can be increased in a short time due to the exchange of the Li.sup.+ in the glass and the Na.sup.+ in the molten salt, making the glass have more excellent mechanical impact resistance. Preferably, Li.sub.2O has a mass percentage of 2%˜10%. More preferably, Li.sub.2O has a mass percentage of 3%˜7%. Most preferably, Li.sub.2O has a mass percentage of 4%˜6%. If the mass percentage of Li.sub.2O is less than 2%, it will become basically difficult for the glass to obtain a higher stress layer depth; if it is higher than 10%, the manufacturing cost of the glass will increase, the expansion coefficient of the glass will significantly increase, and the crystallization tendency of the glass will be so high that the probability of stone defects in glass will significantly increase.

[0032] Na.sub.2O (sodium oxide) is a network outer body oxide of the boro-aluminosilicate glass, which can provide free oxygen to break the Si—O bond, thereby reducing the viscosity and melting temperature of the aluminosilicate glass. Too high content of Na.sub.2O may increase the coefficient of linear thermal expansion, reduce chemical stability, and increase the amount of Na.sub.2O volatilization, resulting in uneven composition of the aluminosilicate glass. Too low content of Na.sub.2O may be not conducive to the melting and molding of glass, and it is not conducive to the chemical exchange of Na ions and K ions to form a compressive stress layer on the surface of the glass to enhance the mechanical strength of the glass. In this embodiment, the Na.sub.2O component takes on the role of exchanging with K ions in the melt to form the compressive stress on the glass surface during tempering, which directly affects the strength performance of the glass. Therefore, in this embodiment, Na.sub.2O preferably has a mass percentage of 4%˜15%, more preferably, a mass percentage of 6%˜12%, and most preferably, a mass percentage of 8%˜10%.

[0033] K.sub.2O (potassium oxide) and Na.sub.2O are both alkali metal oxides, and have similar functions in the glass structure. Substituting Na.sub.2O by a small amount of K.sub.2O can exert a “mixed alkali effect” and make a series of properties of the glass better. K.sub.2O is a component used to improve melting properties and to increase ion exchange rate in chemical reinforcement to obtain the required surface compressive stress and stress layer depth. If the content of K.sub.2O is too high, the weather resistance will decrease. In this embodiment, according to the inventor's analysis of the alkali metal content in the glass, K.sub.2O is set to have a mass percentage of 0˜4%, more preferably, a mass percentage of 0˜3%, and most preferably, a mass percentage of 0˜2%.

[0034] ZrO.sub.2 is mainly in a form of cubic [ZrO.sub.8] coordination in silicate glass. Due to its large ionic radius, it belongs to a network outer body in the glass structure, and it has small solubility in the glass, which will significantly increase the viscosity of the glass. Therefore, the addition amount of ZrO.sub.2 should not exceed 5%. ZrO.sub.2 can improve the acid and alkali resistance and refractive index of the glass. In this embodiment, ZrO.sub.2 preferably has a mass percentage of 0.1%˜5.0%, more preferably, a mass percentage of 1%˜4%, and most preferably, a mass percentage of 3%˜4%.

[0035] MgO (magnesium oxide) is a network outer body oxide, and helps to reduce the melting point of glass. It can reduce the viscosity of glass at high temperature, promote the melting and clarification of glass, improve uniformity, and increase hydrolysis resistance. MgO can also stabilize the glass, improve the durability of the glass, prevent crystallization of the glass, inhibit the movement of alkali metal ions in the glass, and also has the function of improving the elastic modulus of the glass. MgO can enhance the stability of the network space of the glass at low temperature, and can reduce the coefficient of thermal expansion of the glass to a certain extent, but it has a hindering effect on ion exchange. Therefore, in this embodiment, MgO is not an essential component and may be omitted. In this embodiment, MgO preferably has a mass percentage of 0˜6%, more preferably, a mass percentage of 0˜4%, and most preferably, a mass percentage of 0˜2%. If the mass percentage of MgO is higher than 6%, Mg.sup.2+ will seriously hinder the ion exchange capacity of the glass, resulting in a significant reduction in the depth of the compressive stress layer.

[0036] CaO (calcium oxide) may result in relaxation and break of the network formed by silicon-oxygen tetrahedron [SiO.sub.4], and improve the melting properties of glass at high temperatures or make the glass less prone to devitrification. However, too much content will affect the weather resistance of the aluminosilicate glass, and seriously hinder the progress of ion exchange. In this embodiment, CaO is an unnecessary component and may be omitted. Preferably, CaO has a mass percentage of 0˜4%. More preferably, CaO has a mass percentage of 0˜2%.

[0037] SrO (strontium oxide) is similar to calcium oxide and magnesium oxide, all of which can reduce the high temperature viscosity of the glass and facilitate melting, but due to its large ionic radius, SrO will not hinder the exchange process of Li—Na—K ions in the glass structure. Therefore, a small amount of strontium oxide is used to replace part of calcium oxide and magnesium oxide. In this embodiment, SrO preferably has a mass percentage of 0˜4%, and more preferably, a mass percentage of 0˜2%. In this embodiment, SrO may also be omitted.

[0038] ZnO (zinc oxide) belongs to divalent metal oxides, and also has the function of alkaline earth metal oxides. In the silicate glass system, adding part of ZnO materials can effectively reduce the melting temperature of the glass and lower the glass transition temperature T.sub.g, and can also improve the alkali resistance of the glass substrate at the same time. In the aluminosilicate glass body, Zn often exists in the two ligands [ZnO.sub.6] and [ZnO.sub.4]. [ZnO.sub.4] increases with the increase of alkali content, which increases the crystallization tendency of glass. In the present disclosure, a part of zinc oxide is used to replace calcium oxide and magnesium oxide, which is beneficial to maintain the chemical stability of the glass while promoting the rapid progress of ion exchange. Preferably, ZnO has a mass percentage of 0˜4%. More preferably, ZnO has a mass percentage of 0˜2%. In this embodiment, ZnO may also be omitted.

[0039] TiO.sub.2 has a function similar to ZrO.sub.2, and it is a transitional element, which has a certain coloring ability and shows yellow, and can improve the chemical stability of the glass and increase the color temperature of the glass. Therefore, in this embodiment, TiO.sub.2 preferably has a mass percentage of 0˜2%, and more preferably, a mass percentage of 0˜1%. In this embodiment, TiO.sub.2 is not an essential component and may be omitted.

[0040] SnO.sub.2 and CeO.sub.2 often exist in multiple valence states in the glass body, which can increase the UV resistance of the glass and prevent the color change due to the valence change of coloring ions. Moreover, when added alone or in combination, SnO.sub.2 and CeO.sub.2 can also increase the high-temperature defoaming ability of the glass body, which are commonly used clarifying agents. In this embodiment, SnO.sub.2 preferably has a mass percentage of 0˜1%, and more preferably a mass percentage of 0˜0.5%, and CeO.sub.2 preferably has amass percentage of 0˜0.5%. In this embodiment, neither SnO.sub.2 nor CeO.sub.2 is an essential component, and may be omitted.

[0041] Setting the total mass percentage of Li.sub.2O, Na.sub.2O, and K.sub.2O to be greater than or equal to 9% has the following effects. Alkali metals, as a typical glass network modifier, can significantly reduce the melting temperature of glass. Further, in the present disclosure, alkali metal ions are the key to whether the glass can be chemically reinforced to achieve ion exchange so as to obtain a sufficient compressive stress layer on the glass surface. After comprehensive consideration, the total mass percentage of Li.sub.2O, Na.sub.2O, and K.sub.2O should be greater than or equal to 9%.

[0042] Setting the ratio of the mass of Li.sub.2O to the total mass of Li.sub.2O, Na.sub.2O, and K.sub.2O to be (0.22˜0.48):1 has the following effects. In the present disclosure, alkali metals are the key to whether the glass can achieve high-performance chemical reinforcement, and also play different roles during the chemical reinforcement process. A certain proportion of Li is required in the glass body to be exchanged with Na ions and part of K ions in the tempering salt during the first step of chemical tempering. Due to the difference in ion volume, a compressive stress layer with a stress gradient is formed on the surface of the glass, and the depth of the stress layer is relatively deep, the strength and toughness of the glass can be increased. After long-term tests, Li.sub.2O accounts for more than 22% of the total alkali metal content, and should not exceed 48%. In addition to the impacts of the ratio of Li.sub.2O to the total alkali metals on the tempering performance, due to the small relative molecular mass of Li.sub.2O, under same mass percentage, Li.sub.2O has more moles than Na.sub.2O and K.sub.2O, it may drastically reduce the melting temperature of the glass, which is not conducive to the production control, and too much Li.sub.2O will cause glass crystallization. Thus, the proportion of Li.sub.2O in alkali metals should not exceed 48%.

[0043] Setting the total mass percentage of ZrO.sub.2 and Al.sub.2O.sub.3 to be greater than 10% has the following effects. In the present disclosure, ZrO.sub.2 and Al.sub.2O.sub.3 are the key components to realize the speed and difficulty of alkali metal ion exchange during the chemical tempering process, which are used as network intermediates and partially participate in the glass network structure. The macromolecular ZrO.sub.2 is filled in the gaps of the network to form loose structural channels for alkali metal ion exchange, which is conducive to ion exchange in the depth direction of the glass, thereby forming high stress depth and high surface stress. In addition, ZrO.sub.2 and Al.sub.2O.sub.3 components can increase the chemical stability of the glass, so their total mass percentage should be greater than 10%.

[0044] In some embodiments, preferably, the lithium-zirconium-based aluminosilicate glass includes, by mass percentage: 55%˜67% of SiO.sub.2, 13%˜25% of Al.sub.2O.sub.3, 0.5%˜4% of B.sub.2O.sub.3, 3%˜7% of Li.sub.2O, 6%˜12% of Na.sub.2O, 1%˜4% of ZrO.sub.2, and 0˜3% of K.sub.2O. The total mass percentage of Li.sub.2O, Na.sub.2O, and K.sub.2O is greater than or equal to 9%, the total mass percentage of ZrO.sub.2 and Al.sub.2O.sub.3 is greater than 16%, and the ratio of the mass of Li.sub.2O to the total mass of Li.sub.2O, Na.sub.2O, and K.sub.2O is (0.27˜0.41):1.

[0045] In these embodiments, the lithium-zirconium-based aluminosilicate glass may further include at least one of MgO, CaO, SrO, ZnO, and TiO.sub.2. Specifically, MgO has a mass percentage of no greater than 6%, CaO has a mass percentage of no greater than 4%, SrO has a mass percentage of no greater than 4%, ZnO has a mass percentage of no greater than 4%, and TiO.sub.2 has a mass percentage of no greater than 2%.

[0046] Furthermore, MgO has a mass percentage of no greater than 4%, CaO has a mass percentage of no greater than 2%, SrO has a mass percentage of no greater than 2%, ZnO has a mass percentage of no greater than 2%, and TiO.sub.2 has a mass percentage of no greater than 1%.

[0047] In these embodiments, the lithium-zirconium-based aluminosilicate glass may further include at least one of SnO.sub.2 and CeO.sub.2. SnO.sub.2 has a mass percentage of no greater than 1%. Furthermore, SnO.sub.2 has a mass percentage of no greater than 0.5%. CeO.sub.2 has a mass percentage of no greater than 0.5%.

[0048] More preferably, in these embodiments, the lithium-zirconium-based aluminosilicate glass includes: 55%˜67% of SiO.sub.2, 13%˜25% of Al.sub.2O.sub.3, 0.5%˜4% of B.sub.2O.sub.3, 3%˜7% of Li.sub.2O, 6%˜12% of Na.sub.2O, 1%˜4% of ZrO.sub.2, 0˜3% of K.sub.2O, MgO with a mass percentage of no greater than 4%, ZnO with a mass percentage of no greater than 2%, TiO.sub.2 with a mass percentage of no greater than 1%, SnO.sub.2 with a mass percentage of no greater than 1%, and CeO.sub.2 with a mass percentage of no greater than 0.5%. The total mass percentage of Li.sub.2O, Na.sub.2O, and K.sub.2O is greater than or equal to 9%, the total mass percentage of ZrO.sub.2 and Al.sub.2O.sub.3 is greater than 16%, and the ratio of the mass of Li.sub.2O to the total mass of Li.sub.2O, Na.sub.2O, and K.sub.2O is (0.27˜0.41):1.

[0049] It should be noted that in this embodiment, MgO, CaO, SrO, ZnO, TiO.sub.2, SnO.sub.2, and CeO.sub.2 may also be omitted.

[0050] In other embodiments, more preferably, the lithium-zirconium-based aluminosilicate glass includes, by mass percentage: 58%˜64% of SiO.sub.2, 16%˜22% of Al.sub.2O.sub.3, 1%˜2% of B.sub.2O.sub.3, 4%˜6% of Li.sub.2O, 8%˜10% of Na.sub.2O, 3%˜4% of ZrO.sub.2, and 0˜2% of K.sub.2O. The total mass percentage of Li.sub.2O, Na.sub.2O, and K.sub.2O is greater than or equal to 12%, the total mass percentage of ZrO.sub.2 and Al.sub.2O.sub.3 is greater than 19.5%, and the ratio of the mass of Li.sub.2O to the total mass of Li.sub.2O, Na.sub.2O, and K.sub.2O is (0.29˜0.38):1.

[0051] In these embodiments, the lithium-zirconium-based aluminosilicate glass may further include by mass percentage at least one of MgO, CaO, SrO, ZnO, and TiO.sub.2. Specifically, MgO has a mass percentage of no greater than 6%, CaO has a mass percentage of no greater than 4%, SrO has a mass percentage of no greater than 4%, ZnO has a mass percentage of no greater than 4%, and TiO.sub.2 has a mass percentage of no greater than 2%.

[0052] Furthermore, MgO has a mass percentage of no greater than 4%, CaO has a mass percentage of no greater than 2%, SrO has a mass percentage of no greater than 2%, ZnO has a mass percentage of no greater than 2%, and TiO.sub.2 has a mass percentage of no greater than 1%.

[0053] Furthermore, in these embodiments, the lithium-zirconium-based aluminosilicate glass may further include at least one of SnO.sub.2 and CeO.sub.2. SnO.sub.2 has a mass percentage of no greater than 0.5%. CeO.sub.2 has a mass percentage of no greater than 0.5%.

[0054] More preferably, in these embodiments, the lithium-zirconium-based aluminosilicate glass includes: 58%˜64% of SiO.sub.2, 16%˜22% of Al.sub.2O.sub.3, 1%˜2% of B.sub.2O.sub.3, 4%˜6% of Li.sub.2O, 8%˜10% of Na.sub.2O, 3%˜4% of ZrO.sub.2, 0˜2% of K.sub.2O, MgO with a mass percentage of no greater than 4%, ZnO with a mass percentage of no greater than 2%, TiO.sub.2 with a mass percentage of no greater than 1%, SnO.sub.2 with a mass percentage of no greater than 1%, and CeO.sub.2 with a mass percentage of no greater than 0.5%. The total mass percentage of Li.sub.2O, Na.sub.2O, and K.sub.2O is greater than or equal to 12%, the total mass percentage of ZrO.sub.2 and Al.sub.2O.sub.3 is greater than 19.5%, and the ratio of the mass of Li.sub.2O to the total mass of Li.sub.2O, Na.sub.2O, and K.sub.2O is (0.29˜0.38):1.

[0055] It should be noted that in this embodiment, MgO, ZnO, TiO.sub.2, SnO.sub.2, and CeO.sub.2 may also be omitted.

[0056] A conventional technology discloses a glass composition including non-zero amount and less than 1 mol % of P.sub.2O.sub.5 and K.sub.2O, and a ratio of Li.sub.2O to a total amount of B.sub.2O.sub.3, P.sub.2O.sub.5, SiO.sub.2, and Al.sub.2O.sub.3 being less than 0.074. In contrast, since the lithium-zirconium-based aluminosilicate glass according to an embodiment of the present disclosure does not include P.sub.2O.sub.5, the P-B phase separation opacification caused by the addition of P.sub.2O.sub.5 and B.sub.2O.sub.3 can be avoided, so as to avoid the increase in haze (i.e., opacity). And P.sub.2O.sub.5 in the glass will reduce the chemical stability of the glass, especially due to the corrosion of the glass by water vapor and acidic liquids. Moreover, in the embodiments of the present disclosure, the ratio of Li.sub.2O to the total molar amount of B.sub.2O.sub.3, P.sub.2O.sub.5, SiO.sub.2, and Al.sub.2O.sub.3 is generally higher than 0.074, and the amount of Li.sub.2O is also generally higher than that of Na.sub.2O, which can give full play to the advantage of the exchange of Li ions in the glass body with Na and K ions in the tempered salt. As a result, the lithium-zirconium-based aluminosilicate glass in this embodiment has a surface stress value of greater than 800 MPa, and a depth of greater than 130 μm, i.e., the bending strength of the glass and the energy limit to withstand impact are greatly increased.

[0057] Another technology discloses a thin lithium-aluminum-silicon glass having a central tension after tempering of less than 50 Mpa, a surface compressive stress of 600 Mpa˜1200 Mpa, and a bending strength up to 500 MPa. Thus, the depth of the stress layer of this glass should be less than 50 μm. In contrast, after reinforced, the lithium-zirconium-based aluminosilicate glass in this embodiment may has a depth of the stress layer greater than 100 μm, which is much larger than the depth of the stress layer of the tempered glass in the above technology.

[0058] In another conventional technology, the contents of B.sub.2O.sub.3 and ZrO.sub.2 are both low, while the contents of B.sub.2O.sub.3 and ZrO.sub.2 in this embodiment are both greater than 0.1%. If they participate in the formation of the skeleton of the glass body structure, it will be beneficial to the later processing of the glass substrate, and increase the fracture toughness of the glass. After tempering, it forms a surface stress value of greater than 800 MPa and a compressive stress value still being greater than 55 MPa at a depth of 100 μm, so that the mechanical strength and drop resistance of the glass are enhanced.

[0059] Therefore, the conventional glass cover plate can be quickly chemically tempered, and a compressive stress layer greater than 600 MPa is formed on the glass surface, and the depth of the stress layer is generally higher than 35 μm. In contrast, for the lithium-aluminum-silicon glass treated by a special tempering process, the depth of the stress layer can reach more than 100 μm, so as to increase the glass's mechanical strength, impact resistance, friction resistance, resistance to sand and drop resistance, etc. However, the strength of conventional glass is still low.

[0060] The above-mentioned lithium-zirconium-based aluminosilicate glass has at least the following advantages.

[0061] (1) The above-mentioned lithium-zirconium-based aluminosilicate glass has a coefficient of thermal expansion of 84.5×10.sup.−7˜94.9×10.sup.−7 at 20° C.˜300° C., a melting temperature T.sub.2 of 1543° C.˜1638° C., and a glass transition temperature T.sub.g of 497° C.˜ 586° C. After subjected to a special chemical tempering process, the glass has a surface compressive stress CS0 greater than 800 MPa, a compressive stress CS10 of still more than 230 MPa at a depth of 10 μm from the glass surface, a compressive stress CS30 of more than 140 MPa at a depth of 30 μm from the surface, and a maximum depth of stress layer Dol0 produced by ion exchange greater than 136 μm.

[0062] (2) After reinforced, the above-mentioned lithium-zirconium-based aluminosilicate glass has a bending strength greater than 700 MPa, and can withstand a falling ball with energy greater than 0.4 J, which can be used as protective glass for mobile phones, tablets or other mobile smart devices.

[0063] Referring to FIG. 1, a method for preparing a lithium-zirconium-based aluminosilicate glass according to an embodiment is the method for preparing the above-mentioned lithium-zirconium-based aluminosilicate glass, which specifically includes the following steps.

[0064] At step S110, the following raw materials are weighed by mass percentage: 50%˜72% of SiO.sub.2, 10%˜27% of Al.sub.2O.sub.3, 0.1%˜10.0% of B.sub.2O.sub.3, 2%˜10% of Li.sub.2O, 4%˜15% of Na.sub.2O, 0.1%˜5.0% of ZrO.sub.2, and 0˜4% of K.sub.2O, wherein the total mass percentage of Li.sub.2O, Na.sub.2O, and K.sub.2O is greater than or equal to 9%, the total mass percentage of ZrO.sub.2 and Al.sub.2O.sub.3 is greater than 10%, and the ratio of the mass of Li.sub.2O to the total mass of Li.sub.2O, Na.sub.2O, and K.sub.2O is (0.22˜0.48):1.

[0065] At step S120, the above-mentioned raw materials are mixed and melted to obtain a glass paste.

[0066] In an embodiment, the melting in step S120 is carried out at a temperature of 1650° C. for 8 h.

[0067] At step S130, the glass paste is subjected to homogenization treatment.

[0068] In an embodiment, the homogenization treatment in step S130 is carried out at a temperature of 1500° C. for 1 h.

[0069] At step S140, the glass paste is molded, and then subjected to annealing treatment to obtain the lithium-zirconium-based aluminosilicate glass.

[0070] Specifically, in the step of molding the glass paste, a casting molding method is adopted. In an embodiment, the homogenized glass paste is casted onto an iron mold preheated at 450° C. so as to cure and mold the glass paste.

[0071] It should be noted that in the above-mentioned method for preparing lithium-zirconium-based aluminosilicate glass, the glass can be obtained through a conventional flat glass manufacturing process, and the manufacturing method is not limited to float forming process, the overflow down-draw method, Czochralski method, flat-draw method, calendering process, etc.

[0072] A reinforced glass according to an embodiment is obtained from the lithium-zirconium-based aluminosilicate glass according to the above-mentioned embodiments by chemical reinforcement. Specifically, the lithium-zirconium-based aluminosilicate glass includes by mass percentage: 50%˜72% of SiO.sub.2, 10%˜27% of Al.sub.2O.sub.3, 0.1%˜10.0% of B.sub.2O.sub.3, 2%˜10% of Li.sub.2O, 4%˜15% of Na.sub.2O, 0.1%˜5.0% of ZrO.sub.2, and 0˜4% of K.sub.2O, wherein the total mass percentage of Li.sub.2O, Na.sub.2O, and K.sub.2O is greater than or equal to 9%, the total mass percentage of ZrO.sub.2 and Al.sub.2O.sub.3 is greater than 10%, and the ratio of the mass of Li.sub.2O to the total mass of Li.sub.2O, Na.sub.2O, and K.sub.2O is (0.22˜0.48):1.

[0073] Referring to FIG. 2, a method for preparing a reinforced glass according to an embodiment specifically includes the following steps.

[0074] At step S210, the lithium-zirconium-based aluminosilicate glass is subjected to a tempering treatment in a mixed melt of NaNO.sub.3 and KNO.sub.3 at a temperature of 390° C.˜420° C. and a mass ratio of 2:8˜8:2 for 2 h˜6 h.

[0075] Specifically, the lithium-zirconium-based aluminosilicate glass is the lithium-zirconium-based aluminosilicate glass according to the above-mentioned embodiments. Specifically, the lithium-zirconium-based aluminosilicate glass includes by mass percentage: 50%˜72% of SiO.sub.2, 10%˜27% of Al.sub.2O.sub.3, 0.1%˜10.0% of B.sub.2O.sub.3, 2%˜10% of Li.sub.2O, 4%˜15% of Na.sub.2O, 0.1%˜5.0% of ZrO.sub.2, and 0˜4% of K.sub.2O, wherein the total mass percentage of Li.sub.2O, Na.sub.2O, and K.sub.2O is greater than or equal to 9%, the total mass percentage of ZrO.sub.2 and Al.sub.2O.sub.3 is greater than 10%, and the ratio of the mass of Li.sub.2O to the total mass of Li.sub.2O, Na.sub.2O, and K.sub.2O is (0.22˜0.48):1.

[0076] Furthermore, the mass ratio of the mixed melt in step S210 is 6:4˜4:6.

[0077] At step S220, the lithium-zirconium-based aluminosilicate glass is subjected to a tempering treatment in a mixed melt of NaNO.sub.3 and KNO.sub.3 at a temperature of 380° C.˜400° C. and a mass ratio of 0.1:99.9˜15:85 for 2 h˜4 h to obtain a reinforced glass.

[0078] The lithium-zirconium-based aluminosilicate glass is reinforced by a two-step mixed salt method. The reinforcement by using two-step mixed salt method has the following effects. Through the two-step chemical tempering method, the ion species are selectively exchanged. The first step is mainly the exchange of Li ions in the glass with Na ions and K ions in the tempering salt. The Na—Li exchange will result in a compressive stress layer with a small compressive stress value and a high stress depth, which is accompanied by part of Li—K and Na—K exchange, forming a larger stress to compensate for the low stress value in the high depth direction. In the second step, the tempering salt with low temperature and high K ion content is used for tempering. The Na ions in the glass and the K ions in the tempering salt are rapidly exchanged to form a dense stress layer with lower stress depth and high compressive stress value on the glass surface, and finally a composite stress layer is formed, which is mainly characterized by having a high stress layer exceeding 700 MPa on the glass surface and a stress layer depth exceeding 100 μm or even higher in the depth direction.

[0079] The mass ratio of sodium nitrate to potassium nitrate in step S210 is set to 2:8˜8:2 mainly for the purpose of achieving chemical exchange between Na ions and Li ions in the glass to form a stress layer with sufficient depth. However, since the radii of Na ions and Li ions are not much different, and there is enough space in the glass structure to meet the conversion of Na—Li ions, the depth of the formed stress layer is deep, but the stress value is low. By adding K with a large ionic radius to the tempering salt, the Li—K and Na—K exchange can be realized in the stress direction and the partial compressive stress value is increased. Therefore, the mass ratio of sodium nitrate and potassium nitrate in the first step is set to 2:8˜8:2. The mass ratio of sodium nitrate to potassium nitrate in step S220 is set to 0.1:99.9˜15:85 mainly for the purpose of achieving exchange between Na ions in the glass and K ions in the tempering salt to form a stress layer with a high compressive stress value on the glass surface, which forms a composite compressive stress layer with the stress layer formed by the tempering in the first step, thereby increasing the strength and toughness of the glass.

[0080] In the two-step chemical tempering process, the temperature of the mixed melt in step S210 is usually higher than the temperature of the mixed melt in step S220 by 10° C. to 20° C. Since for the two elements of the tempering process: temperature and time, with same tempering salt, the longer the treatment time and the higher the temperature, the deeper the depth of the stress layer formed, but the stress value will be significantly reduced. The purposes of the two tempering steps in the present disclosure are different. The purpose of the first step is to form a stress layer with sufficient depth (greater than 100 μm), and the higher the stress value, the better. Therefore, a higher temperature is selected in the first step, usually 390° C.˜420° C., and the time is 2 h˜6 h. The purpose of the second step is to form a high-stress stress layer (greater than 700 MPa) with a certain depth, so that in the second step, a lower temperature and a short time are required, usually between 380° C. and 400° C., and the time is 2 h˜4 h. The main reason for not selecting a longer time is that the tempering period is too long, the efficiency and yield are low, and the cost is high and it is not suitable for mass production.

[0081] The reinforced glass obtained by reinforcing the lithium-zirconium-based aluminosilicate glass by the above-mentioned method has a bending strength greater than 700 MPa, and can withstand a falling ball with energy greater than 0.4 J, which can effectively avoid or reduce the breakage of the glass of the screen or other cover plate of smart devices such as mobile phones due to accidentally falling on the ground. Thereby, it can be used as protective glass for mobile phones, tablets, or other mobile smart devices.

[0082] The display device according to an embodiment includes the above-mentioned lithium-zirconium-based aluminosilicate glass or the above-mentioned reinforced glass or the reinforced glass prepared by the above-mentioned method for preparing the reinforced glass. The display device includes smart mobile devices, digital cameras, etc. The above-mentioned lithium-zirconium-based aluminosilicate glass or the reinforced glass has high strength and can be used as a protective glass to prevent smart mobile devices from being damaged due to accidental falling.

[0083] The following are specific examples.

[0084] The preparation process of the lithium-zirconium-based aluminosilicate glass of Examples 1 to 21 is specifically as follows.

[0085] According to the compositions (mass percentages) of Example 1 to Example 21 in the following Table 1 to Table 3, the ingredients were fully and uniformly mixed, then melted in a platinum crucible at 1650° C. for 8 h under stirring with a platinum stirring paddle. After the stirring paddle was drawn out, the melt was cooled down to 1500° C., and kept for 1 h for homogenization. Then the melt was cast onto an iron mold to form a glass block with a size of about 80 mm×160 mm. The mold was preheated to 450° C. before casting, and the glass block was transferred to an annealing furnace for annealing (under a temperature of 590° C.) immediately after hardening, kept for 2 h, then cooled down to 140° C. for 6 h, and then cooled naturally, to obtain a lithium-zirconium-based aluminosilicate glass.

[0086] The reinforcement process of the lithium-zirconium-based aluminosilicate glass of Examples 1 to 7 is specifically as follows.

[0087] The lithium-zirconium-based aluminosilicate glasses obtained in the above Examples 1 to 7 were processed into 50 mm×50 mm×0.7 mm double side polished glass sheets. The glass sheets were tempered in a mixed melt of NaNO.sub.3:KNO.sub.3=1:1 (mass ratio) at 395° C. for 4 h, and then transferred into a mixed melt of NaNO.sub.3:KNO.sub.3=8:92 (mass ratio) at 380° C. for tempering for 2 h, to obtain reinforced glasses.

[0088] The reinforcement process of the lithium-zirconium-based aluminosilicate glass of Examples 8 to 14 is specifically as follows.

[0089] The lithium-zirconium-based aluminosilicate glasses obtained in the above Examples 8 to 14 were processed into 50 mm×50 mm×0.7 mm double side polished glass sheets. The glass sheets were tempered in a mixed melt of NaNO.sub.3:KNO.sub.3=8:2 (mass ratio) at 420° C. for 2 h, and then transferred into a mixed melt of NaNO.sub.3:KNO.sub.3=15:85 (mass ratio) at 400° C. for tempering for 2 h, to obtain reinforced glasses.

[0090] The reinforcement process of the lithium-zirconium-based aluminosilicate glass of Examples 15 to 21 is specifically as follows.

[0091] The lithium-zirconium-based aluminosilicate glasses obtained in the above Examples 15 to 21 were processed into 50 mm×50 mm×0.7 mm double side polished glass sheets. The glass sheets were tempered in a mixed melt of NaNO.sub.3:KNO.sub.3=2:8 (mass ratio) at 405° C. for 6 h, and then transferred into a mixed melt of NaNO.sub.3:KNO.sub.3=0.1:99.9 (mass ratio) at 390° C. for tempering for 4 h, to obtain reinforced glasses.

[0092] The preparation process of the lithium-zirconium-based aluminosilicate glass of Comparative Examples 1 to 13 is similar to the preparation process of the lithium-zirconium-based aluminosilicate glass of Examples 1 to 21, except that the compositions of the raw materials are as shown in Tables 4 to 5.

[0093] The reinforcement process of the lithium-zirconium-based aluminosilicate glass of Comparative Examples 1 to 10 is similar to the reinforcement process of the lithium-zirconium-based aluminosilicate glass of Examples 1 to 7, and will not be repeated herein.

[0094] The reinforcement process of the lithium-zirconium-based aluminosilicate glass of Comparative Example 11 is specifically as follows.

[0095] The lithium-zirconium-based aluminosilicate glass obtained in the above Comparative Example 11 was processed into a 50 mm×50 mm×0.7 mm double side polished glass sheet. The glass sheet was tempered in a mixed melt of NaNO.sub.3:KNO.sub.3=1:1 (mass ratio) at 395° C. for 6 h, to obtain a reinforced glass.

[0096] The reinforcement process of the lithium-zirconium-based aluminosilicate glass of Comparative Example 12 is specifically as follows.

[0097] The lithium-zirconium-based aluminosilicate glass obtained in the above Comparative Example 12 was processed into a 50 mm×50 mm×0.7 mm double side polished glass sheet. The glass sheet was tempered in a mixed melt of NaNO.sub.3:KNO.sub.3=8:92 (mass ratio) at 380° C. for 6 h, to obtain a reinforced glass.

[0098] The reinforcement process of the lithium-zirconium-based aluminosilicate glass of Comparative Example 13 is specifically as follows.

[0099] The lithium-zirconium-based aluminosilicate glass obtained in the above Comparative Example 13 was processed into a 50 mm×50 mm×0.7 mm double side polished glass sheet. The glass sheet was tempered in a mixed melt of NaNO.sub.3:KNO.sub.3=8:92 (mass ratio) at 395° C. for 4 h, and then transferred into a mixed melt of NaNO.sub.3:KNO.sub.3=1:1 (mass ratio) at 380° C. for tempering for 2 h, to obtain a reinforced glass.

[0100] Testing:

[0101] The lithium-zirconium-based aluminosilicate glasses obtained in the above-mentioned Examples 1 to 21 and Comparative Examples 1 to 13 were all processed into glass samples of (p 5 mm×50 mm. The thermal expansion curves were measured by using a NETZSCH Thermal Dilatometer (NETZSCH-DIL 402 PC) at a heating rate of 4° C./min. The strain point temperatures T.sub.g, the expansion softening point temperatures T.sub.s, and the coefficients of thermal expansion CTE of the glass samples in the range of 20° C.˜300° C. were measured through the built-in software, and recorded in the Tables 1 to 5.

[0102] 250 g of each of the lithium-zirconium-based aluminosilicate glasses obtained in Examples 1 to 21 and Comparative Examples 1 to 13 was taken to measure the high-temperature viscosity by using a glass high-temperature viscometer (ORTON, RSV-1600). The temperature at which the viscosity was 102 dPa.Math.S was defined as the glass melting temperature T.sub.2, and the temperatures at which the viscosities were 103 dPa.Math.S, 104 dPa.Math.S, and 105 dPa.Math.S were defined as T.sub.3, T.sub.4, and T.sub.5, respectively, and their values were correspondingly recorded in Tables 1 to 5.

[0103] For the reinforced glass, the stress tester FSM6000UV and SLP1000 (ORIHARA, Japan) were used to measure the surface stress value CS0, the compressive stress value CS10 at the depth of 10 μm, the compressive stress value CS30 at the depth of 30 μm and the compressive stress value CS100 at the depth of 100 μm, the maximum stress layer depth Dol0, and the stress layer depth Dol600 at 600 MPa, and results were recorded in Tables 1 to 5.

[0104] The lithium-zirconium-based aluminosilicate glass of Examples 1 to 21 and Comparative Examples 1 to 10 were cut into 70 mm×140 mm×0.7 mm glass sheets by an STX-1203 wire cutting machine (Shenyang, Kejing). The glass sheets were thinned and polished by an HD-640-5L double side grinding and polishing machine (Shenzhen, Hyde), and then edged by computer numerical control (CNC). After cleaning, they were tempered in a mixed melt of NaNO.sub.3:KNO.sub.3=1:1 (mass ratio) at 395° C. for 4 h, and then transferred to a mixed melt of NaNO.sub.3:KNO.sub.3=8:92 (mass ratio) at 380° C. for tempering for 2 h, to obtain reinforced glass substrates. The four-point bending strength was measured by PT-307A universal tester (Precise Test) and the energy of the falling ball withstood at the center of the glass substrate was measured by PT-706 falling ball tester. A 64 g of solid steel ball was used to hit the center, and if the center point did not break after three times of hits, then the height H mm was recorded. The falling ball energy was calculated by C=64×H/10000 (in a unit of J), and recorded in Tables 1 to 5.

[0105] The lithium-zirconium-based aluminosilicate glass of Comparative Examples 11 to 13 were cut into 70 mm×140 mm×0.7 mm glass sheets by the STX-1203 wire cutting machine (Shenyang, Kejing). The glass sheets were thinned and polished by the HD-640-5L double side grinding and polishing machine (Shenzhen, Hyde), and then edged by CNC. After cleaning, they were reinforced according to the above-mentioned reinforcement process of Comparative Examples 11 to 13, to obtain reinforced glass substrates. The four-point bending strength was measured by PT-307A universal tester (Precise Test) and the energy of the falling ball withstood at the center of the glass substrate was measured by PT-706 falling ball tester. A 64 g of solid steel ball was used to hit the center, and if the center point did not break after three times of hits, then the height H mm was recorded. The falling ball energy was calculated by C=64×H/10000 (in a unit of J), and recorded in Table 5.

[0106] The lithium-zirconium-based aluminosilicate glass of Examples 1 to 7 in Table 1 includes by mass percentage: 50%˜72% of SiO.sub.2, 10%˜27% of Al.sub.2O.sub.3, 0.1%˜10.0% of B.sub.2O.sub.3, 2%˜10% of Li.sub.2O, 4%˜ 15% of Na.sub.2O, 0.10%˜5.0% of ZrO.sub.2, 0˜4% of K.sub.2O, 0˜6% of MgO, 0˜4% of CaO, 0˜4% of SrO, 0˜4% of ZnO, 0˜2% of TiO.sub.2, 0˜1% of SnO.sub.2, and 0˜0.5% of CeO.sub.2. Wherein the total mass percentage of Li.sub.2O, Na.sub.2O, and K.sub.2O is greater than or equal to 9%, the total mass percentage of ZrO.sub.2 and Al.sub.2O.sub.2 is greater than 10%, and the ratio of the mass of Li.sub.2O to the total mass of Li.sub.2O, Na.sub.2O, and K.sub.2O is (0.22˜0.48):1.

[0107] Regarding the lithium-zirconium-based aluminosilicate glass obtained in the Examples 1 to 7, it is found that the lithium-zirconium-based aluminosilicate glass with the above composition characteristics has a coefficient of thermal expansion of 84.5×10.sup.−7˜94.9×10.sup.−7 at 20° C.˜300° C., a melting temperature T.sub.2 of 1543° C.˜1638° C., and a glass transition point temperature T.sub.g of 497° C.˜586° C. The lithium-zirconium-based aluminosilicate glass of Examples 1 to 7 was tempered in the mixed melt of NaNO.sub.3:KNO.sub.3=1:1 (mass ratio) at 395° C. for 4 h, and then transferred to the mixed melt of NaNO.sub.3:KNO.sub.3=8:92 (mass ratio) at 380° C. for tempering for 2 h, to obtain reinforced glass. The obtained reinforced glass has a surface compressive stress CS0 of greater than 800 MPa, a compressive stress CS10 of still more than 230 MPa at a depth of 10 μm from the glass surface, and a compressive stress CS30 of more than 140 MPa at a depth of 30 μm from the surface, and a stress depth Dol0 of greater than 136 μm when the composite compressive stress produced by ion exchange drops to 0 MPa (the detection limit of the instrument). The reinforced glass has a bending strength of greater than 740 MPa, and can withstand a falling ball energy of greater than 0.32 J.

TABLE-US-00001 TABLE 1 Composition and performance data of the lithium-zirconium-based aluminosilicate glass of Examples 1 to 7 Example Example Example Example Example Example Example Composition (%) 1 2 3 4 5 6 7 SiO.sub.2 50.00 54.00 58.00 59.00 63.00 72.00 62.00 Al.sub.2O.sub.3 27.00 18.00 22.00 18.00 14.00 12.00 10.00 B.sub.2O.sub.3 0.10 0.50 1.50 2.50 10.00 1.00 2.50 Li.sub.2O 2.00 6.00 3.50 6.00 4.00 6.00 10.00 Na.sub.2O 7.00 8.50 6.00 7.00 4.00 6.00 15.00 K.sub.2O — — 1.00 1.50 4.00 0.50 0.40 MgO 6.00 5.00 1.00 1.00 — 1.00 — CaO — 4.00 — — — — — SrO — — 4.00 — — — — ZnO — — — 4.00 — — — ZrO.sub.2 5.00 4.00 3.00 1.00 1.00 0.50 0.10 TiO.sub.2 2.00 — — — — — — SnO.sub.2 0.40 — — — — 1.00 — CeO.sub.2 0.50 — — — — — — Li.sub.2O + Na.sub.2O + K.sub.2O 9 14.5 10.5 14.5 12 12.5 25.4 Li.sub.2O/(Li.sub.2O + Na.sub.2O + K.sub.2O) 0.22 0.41 0.33 0.41 0.33 0.48 0.39 Al.sub.2O.sub.3 + ZrO.sub.2 32 22 25 19 15 12.5 10.1 Coefficient of thermal 94.9 91.2 86.1 89.3 90.1 84.5 90.8 expansion CTE (20° C.~300° C., ×10.sup.−7) Glass transition point 586 562 532 512 504 536 497 temperature T.sub.g (° C.) Expansion softening 638 613 594 574 559 598 544 point temperature T.sub.s (° C.) T.sub.2 (η viscosity, logη = 2, ° C.) 1638 1611 1594 1572 1567 1597 1543 T.sub.3 (η viscosity, logη = 3, ° C.) 1386 1326 1318 1282 1268 1320 1219 T.sub.4 (η viscosity, logη = 4, ° C.) 1189 1138 1122 1083 1069 1129 1022 T.sub.5 (η viscosity, logη = 5, ° C.) 1065 1009 983 966 954 994 921 CS0(MPa) 1074 878 1004 965 816 869 835 CS10(MPa) 362 254 345 317 229 242 234 CS30(MPa) 212 152 202 185 141 149 143 CS100(MPa) 98 59 93 84 55 61 60 Dol0(μm) 192 142 186 165 126 138 136 Dol600(μm) 7.8 5.5 7 6.3 5.1 5.4 5.3 Bending strength (MPa) 864 789 885 846 743 823 762 Impact energy 0.512 0.384 0.544 0.480 0.320 0.448 0.384 withstanding (J) Note that: CS0 is a surface stress value; CS10 is a compressive stress value at a depth of 10 μm; CS30 is a compressive stress value at a depth of 30 μm; CS100 is a compressive stress value at a depth of 100 μm; Dol0 is a maximum stress layer depth; and D0l600 is a stress layer depth at 600 MPa.

[0108] Preferred ratios of the compositions of the lithium-zirconium-based aluminosilicate glass are listed in Table 2. The lithium-zirconium-based aluminosilicate glass of Examples 8 to 14 includes by mass percentage: 55%˜67% of SiO.sub.2, 13%˜25% of Al.sub.2O.sub.3, 0.5%˜4% of B.sub.2O.sub.3, 3%˜7% of Li.sub.2O, 6%˜12% of Na.sub.2O, 1%˜4% of ZrO.sub.2, 0˜3% of K.sub.2O, 0˜4% of MgO, 0˜2% of CaO, 0˜2% of SrO, 0˜2% of ZnO, 0˜1% of TiO.sub.2, 0˜0.5% of SnO.sub.2, and 0˜0.5% of CeO.sub.2. Wherein the total mass percentage of Li.sub.2O, Na.sub.2O, and K.sub.2O is greater than or equal to 9%, the total mass percentage of ZrO.sub.2 and Al.sub.2O.sub.3 is greater than 16%, and the ratio of the mass of Li.sub.2O to the total mass of Li.sub.2O, Na.sub.2O, and K.sub.2O is (0.27˜0.41):1.

[0109] Regarding the lithium-zirconium-based aluminosilicate glass obtained in the Examples 8 to 14, it is found that the lithium-zirconium-based aluminosilicate glass with the above composition characteristics has a coefficient of thermal expansion of 84.3×10.sup.−7˜91.4×10.sup.−7 at 20° C.˜300° C., a melting temperature T.sub.2 of 1581° C.˜1613° C., and a glass transition point temperature T.sub.g of 503° C.˜558° C. The lithium-zirconium-based aluminosilicate glass of Examples 8 to 14 was tempered in the mixed melt of NaNO.sub.3:KNO.sub.3=8:2 (mass ratio) at 420° C. for 2 h, and then transferred to the mixed melt of NaNO.sub.3:KNO.sub.3=15:85 (mass ratio) at 400° C. for tempering for 2 h, to obtain reinforced glass. The obtained reinforced glass has a surface compressive stress CS0 of greater than 900 MPa, a compressive stress CS10 of still more than 275 MPa at a depth of 10 μm from the glass surface, and a compressive stress CS30 of more than 145 MPa at a depth of 30 μm from the surface, and a stress depth Dol0 of greater than 145 μm when the composite compressive stress produced by ion exchange drops to 0 MPa (the detection limit of the instrument). The reinforced glass has a bending strength of greater than 810 MPa, and can withstand a falling ball energy of greater than 0.48 J.

TABLE-US-00002 TABLE 2 Composition and performance data of the lithium-zirconium-based aluminosilicate glass of Examples 8 to 14 Example Example Example Example Example Example Example Composition 8 9 10 11 12 13 14 SiO.sub.2 55 57 59 59 63 65 67 Al.sub.2O.sub.3 25 23 21 19 17 15 13 B.sub.2O.sub.3 2 4 2 1 1 0.5 3 Li.sub.2O 4 3 5 5 3 7 5 Na.sub.2O 8 8 12 9.5 6 10 9 K.sub.2O 3 — — 0.5 — — — MgO — — — — 4 — — CaO — — — — 2 — — SrO — — — 2 — — — ZnO — 2 — — — — — ZrO.sub.2 3 2 1 3.5 4 1.5 3 TiO.sub.2 — 1 — — — — — SnO.sub.2 — — — — — 0.5 — CeO.sub.2 — — — 0.5 — 0.5 — Li.sub.2O + Na.sub.2O + K.sub.2O 15 11 17 15 9 17 14 Li.sub.2O/(Li.sub.2O + Na.sub.2O + K.sub.2O) 0.27 0.27 0.29 0.33 0.33 0.41 0.36 Al.sub.2O.sub.3 + ZrO.sub.2 28 25 22 22.5 21 16.5 16 Coefficient of thermal 91.4 90.2 90.8 88.7 84.3 86.4 84.8 expansion CTE (20° C.~300° C., ×10.sup.−7) Glass transition point 558 539 512 521 536 514 503 temperahire T.sub.g (° C.) Expansion softening point 614 601 575 579 594 572 559 temperature T.sub.s (° C.) T.sub.2 (η viscosity, logη = 2, ° C.) 1613 1602 1592 1597 1599 1588 1581 T.sub.3 (η viscosity, logη = 3, ° C.) 1338 1306 1288 1292 1312 1283 1279 T.sub.4 (η viscosity, logη = 4, ° C.) 1154 1120 1103 1118 1129 1097 1086 T.sub.5 (η viscosity, logη = 5, ° C.) 1029 998 979 997 1007 995 960 CS0(MPa) 1018 914 974 982 908 958 942 CS10(MPa) 359 288 331 336 275 314 304 CS30(MPa) 184 158 195 198 146 175 162 CS100(MPa) 90 69 86 88 65 79 78 Dol0(μm) 189 148 164 172 146 167 165 Dol600(μm) 6.7 5.2 6.2 6.4 5.6 6.1 5.9 Bending strength (MPa) 889 835 892 904 816 838 845 Impact energy 0.544 0.512 0.480 0.512 0.480 0.480 0.480 withstanding (J)

[0110] More preferred ratios of the compositions of the lithium-zirconium-based aluminosilicate glass are listed in Table 3. The lithium-zirconium-based aluminosilicate glass of Examples 15 to 21 includes by mass percentage: 58%˜64% of SiO.sub.2, 16%˜22% of Al.sub.2O.sub.3, 1%˜2% of B.sub.2O.sub.3, 4%˜6% of Li.sub.2O, 8%˜10% of Na.sub.2O, 3%˜4% of ZrO.sub.2, 0˜2% of K.sub.2O, 0˜2% of MgO, 0˜2% of ZnO, 0˜0.5% of SnO.sub.2, and 0˜0.5% of CeO.sub.2. Wherein the total mass percentage of Li.sub.2O, Na.sub.2O, and K.sub.2O is greater than or equal to 9%, the total mass percentage of ZrO.sub.2 and Al.sub.2O.sub.3 is greater than 19.50%, and the ratio of the mass of Li.sub.2O to the total mass of Li.sub.2O, Na.sub.2O, and K.sub.2O is (0.29˜0.38):1.

[0111] Regarding the lithium-zirconium-based aluminosilicate glass obtained in the Examples 15 to 21, it is found that the lithium-zirconium-based aluminosilicate glass with the above composition characteristics has a coefficient of thermal expansion of 82.9×10.sup.−7 at 20° S˜300° C., a melting temperature T.sub.2 of 1586° C.˜1612° C., and a glass transition point temperature T.sub.g of 5050° C.˜546° C. The lithium-zirconium-based aluminosilicate glass of Examples 15 to 21 was tempered in the mixed melt of NaNO.sub.3:KNO.sub.3=2:8 (mass ratio) at 405° C. for 6 h, and then transferred to the mixed melt of NaNO.sub.3:KNO.sub.3=08199.9 (mass ratio) at 390° C. for tempering for 4 h, to obtain reinforced glass. The obtained reinforced glass has a surface compressive stress CS0 of greater than 915 MPa, a compressive stress CS10 of more than still 300 MPa at a depth of 10 μm from the glass surface, and a compressive stress CS30 of more than 160 MPa at a depth of 30 μm from the surface, and a stress depth Dol0 of greater than 150 μm when the composite compressive stress produced by ion exchange drops to 0 MPa (the detection limit of the instrument). The reinforced glass has a bending strength of greater than 820 MPa, and can withstand a falling ball energy of greater than 0.48 J.

TABLE-US-00003 TABLE 3 Composition and performance data of the lithium-zirconium-based aluminosilicate glass of Examples 15 to 21 Example Example Example Example Example Example Example Composition (%) 15 16 17 18 19 20 21 SiO.sub.2 58 59.5 60 61 61.5 64 63 Al.sub.2O.sub.3 21 20.5 20 18 22 16 16 B.sub.2O.sub.3 2 2 1 1.5 1 1.5 1.5 Li.sub.2O 5.5 4 6 4.5 4 5 5 Na.sub.2O 10 10 8 8 8 9 9 K.sub.2O — — 2 MgO — — — 2 — — — CaO — — — — — — — SrO — — — — — — — ZnO — — — — — 2 ZrO.sub.2 3.5 4 3 3 3.5 4 3.5 TiO.sub.2 — — — 1 — — — SnO.sub.2 — — — 0.5 — — — CeO.sub.2 — — — 0.5 — 0.5 — Li.sub.2O + Na.sub.2O + K.sub.2O 15.5 14 16 12.5 12 14 14 Li.sub.2O/(Li.sub.2O + Na.sub.2O + K.sub.2O) 0.35 0.29 0.38 0.36 0.33 0.36 0.36 Al.sub.2O.sub.3 + ZrO.sub.2 24.5 24.5 23 21 25.5 20 19.5 Coefficient of thermal 89.8 88.9 88.1 86.5 82.9 83.6 84.4 expansion CTE (20° C.~300° C., ×10.sup.−7) Glass transition point 511 505 506 521 546 506 519 temperature T.sub.g (° C.) Expansion softening 576 564 562 582 608 568 587 point temperature T.sub.s (° C.) T.sub.2 (η viscosity, logη = 2, ° C.) 1597 1587 1586 1589 1612 1589 1603 T.sub.3 (η viscosity, logη = 3, ° C.) 1306 1293 1294 1288 1334 1295 1311 T.sub.4 (η viscosity, logη = 4, ° C.) 1117 1098 1093 1094 1146 1099 1124 T.sub.5 (η viscosity, logη = 5, ° C.) 981 976 964 959 1022 964 996 CS0(MPa) 982 969 1024 954 1066 918 922 CS10(MPa) 335 328 364 318 392 302 304 CS30(MPa) 192 189 206 178 235 165 164 CS100(MPa) 85 82 85 80 92 78 80 Dol0(μm) 162 158 174 154 164 183 182 Dol600(μm) 6.3 6.2 6.8 6.1 6.3 7.2 7.2 Bending strength (MPa) 854 843 896 885 914 827 844 Impact energy 0.544 0.512 0.544 0.512 0.544 0.480 0.512 withstanding (J)

[0112] Composition and performance data of the lithium-zirconium-based aluminosilicate glass of Comparative Examples 1 to 7 are shown in Table 4 below. It can be seen from Table 4 that the total content of alkali metals in Comparative Example 1 is less than 9%, and its T.sub.2 melting temperature is as high as 1652° C., at which mass production cannot be realized in actual glass furnaces, especially float furnaces. Generally, the melting temperature T.sub.2 is required to be controlled below 1640° C. Such a high melting temperature will result in increase of the energy consumption of natural gas, electric energy, etc., on one hand. On the other hand, it will result in reduction of the life of the furnaces, refractory bricks, and related equipment, and increase of costs. It is also very difficult to control during forming stage.

[0113] In Comparative Example 2, 0% Li.sub.2O is contained, which results in only a small amount of Na—K exchange in the first tempering, and Li—Na exchange cannot be formed to form a high-stress layer depth. Therefore, its Dol0 (μm) is 34.8 μm, CS30 (MPa) is 24 MPa, and CS100 (MPa) is 0 MPa. Thereby, its bending strength is 608 MPa, and it can withstand a falling ball energy of 0.24 J, which are much lower than Li-containing aluminosilicate glass.

[0114] In Comparative Example 3, no Na.sub.2O is contained, and since Li.sub.2O/(Li.sub.2O+Na.sub.2O+K.sub.2O) is 0.9, the number of moles of Li.sub.2O is greatly increased, and the mole content is close to 20%, which leads to a sharp decrease in the melting temperature of the glass, and it is difficult to control the float forming. And due to the increase of Li.sub.2O content, a devitrification phenomenon occurs in the glass. The occurrence of turbidity leads to the decrease of transmittance, the bending strength and the falling ball energy withstanding are reduced.

[0115] In Comparative Example 4, the content of Li.sub.2O is 2.90%, the content of Na.sub.2O is 10.10%, and Li.sub.2O/(Li.sub.2O+Na.sub.2O+K.sub.2O) is 0.2, which is less than 0.22. As a result, Dol0 is 98 μm after the glass is chemically tempered by the two-step tempering method, which is much lower than the embodiment of the present disclosure. Its final bending strength and the falling ball energy withstanding both are reduced, and the falling ball energy withstanding is reduced to 0.24 J.

[0116] In Comparative Example 5, the content of Li.sub.2O is 6.60%, the content of K.sub.2O is 1.40%, and Li.sub.2O/(Li.sub.2O+Na.sub.2O+K.sub.2O) is 0.55, which is greater than 0.48. After glass tempering, CS0 (MPa) is 668 MPa, which is less than 700 MPa, which will result in the reduction of the bending strength and falling ball strength of the glass. And a small amount of devitrification occurs in the glass body, which causes its bending strength to be reduced, and the falling ball energy withstanding to be reduced to 0.200 J.

[0117] In Comparative Example 6, the content of Al.sub.2O.sub.3 is 9.00, which is less than 100; the content of Al.sub.2O.sub.3+ZrO.sub.2 is 9.50%, which is less than 10%; and the content of B.sub.2O.sub.3 is 4.00%. Decreasing the content of Al.sub.2O.sub.3+ZrO.sub.2, especially Al.sub.2O.sub.3, will seriously affect the glass structure. Al.sub.2O.sub.3 participates in the structure as a glass intermediate, if its content is too low, the tempering performance of the glass body, especially the Na—K exchange in the second step, will decrease. As a result, the stress layer and the depth of the stress layer on the glass surface are reduced, and its strength, especially the bending strength and the falling ball strength are reduced.

[0118] In Comparative Example 7, no ZrO.sub.2 is contained, and the content of Al.sub.2O.sub.3 is 10.10. Compared with Example 7, since there is no ZrO.sub.2 filled in the gap of the glass structure, a sufficiently stable glass structure space cannot be formed. When it is impacted by an external force, there is no large field strength ion Zr.sup.4+ in the gap of the structure to offset part of the external stress. As a result, it is easy to produce stress concentration, leading to a break of the glass products, and a reduction of the bending strength and the falling ball energy withstanding of the glass.

TABLE-US-00004 TABLE 4 Composition and performance data of the lithium-zirconium-based aluminosilicate glass of Comparative Examples 1 to 7 Comparative Comparative Comparative Comparative Comparative Comparative Comparative Composition (%) Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 SiO.sub.2 51.00 54.00 58.00 59.00 63.00 72.00 62.00 Al.sub.2O.sub.3 27.00 18.00 22.00 18.00 14.00 9.00 10.10 B.sub.2O.sub.3 0.10 0.50 1.50 2.50 10.00 4.00 2.50 Li.sub.2O 2.00 — 9.50 2.90 6.60 6.00 10.00 Na.sub.2O 6.00 14.50 — 10.10 4.00 6.00 15.00 K.sub.2O — — 1.00 1.50 1.40 0.50 0.40 MgO 6.00 5.00 1.00 1.00 — 1.00 — CaO — 4.00 — — — — — SrO — — 4.00 — — — — ZnO — — — 4.00 — — — ZrO.sub.2 5.00 4.00 3.00 1.00 1.00 0.50 — TiO.sub.2 2.00 — — — — — — SnO.sub.2 0.40 — — — — 1.00 — CeO.sub.2 0.50 — — — — — — Li.sub.2O + Na.sub.2O + K.sub.2O 8 14.5 10.5 14.5 12 12.5 25.4 Li.sub.2O/(Li.sub.2O + Na.sub.2O + K.sub.2O) 0.25 0 0.90 0.2 0.55 0.48 0.39 Al.sub.2O.sub.3 + ZrO.sub.2 32 22 25 19 15 9.5 10.1 Coefficient of thermal 92.4 89.4 95.6 84.2 92.4 83.2 90.8 expansion CTE (20° C.~300° C., ×10.sup.−7) Glass transition point 604 568 508 529 498 514 497 temperature T.sub.g (° C.) Expansion softening 662 619 552 589 536 553 544 point temperature T.sub.s (° C.) T.sub.2 (η viscosity, 1652 1623 1483 1592 1545 1562 1543 logη = 2. ° C.) T.sub.3 (η viscosity, 1403 1357 1108 1294 1228 1256 1219 logη = 3, ° C.) T.sub.4 (η viscosity, 1220 1152 926 1103 1032 1079 1022 logη = 4, ° C.) T5 (η viscosity, 1104 1036 867 989 924 942 921 logη = 5, ° C.) CS0(MPa) 1086 989 788 976 668 726 819 CS10(MPa) 358 645 189 212 179 184 203 CS30(MPa) 233 24 104 124 121 132 121 CS100(MPa) 102 0 45 64 52 61 62 Dol0(μm) 187 34.8 194 98 169 124 106 Dol600(μm) 7.8 11.2 3.2 5.9 4.8 3.4 4.8 Bending strength (MPa) 854 608 722 748 598 625 654 Impact energy 0.512 0.240 0.200 0.240 0.200 0.240 0.280 withstanding (J) Devitrification or not NO NO Devitrification NO Slight NO NO devitrification

[0119] Composition and performance data of the lithium-zirconium-based aluminosilicate glass of Comparative Examples 8 to 13 are listed in Table 5 below. It can be seen from Table 5 that in Comparative Example 8, 1% of P.sub.2O.sub.5 is contained, and the content of Al.sub.2O.sub.3 is 26%. Compared with Example 1, after tempering, the compressive stress value is reduced, the depth of the stress layer is slightly increased, and the tensile stress value at the center of the glass is increased, leading to a certain degree of reduction for both the bending strength and the impact energy of falling ball withstood of the glass.

[0120] In Comparative Example 9, no B.sub.2O.sub.3 is contained, and the content of SiO.sub.2 is 54.50%. Compared with Example 2, the stress value and stress depth after tempering are slightly improved, but since no boron oxide, mainly boron-oxygen triangle and boron-oxygen tetrahedron, is participated in the glass network structure, when the glass is subjected to an external impact, there is no buffer structure to offset this part of the stress, which is likely to cause stress concentration, resulting in a decrease in various strength properties. It can be clearly seen from Comparative Example 9 that the tempering performance is increased, but the bending strength and impact energy withstanding of the glass are reduced.

[0121] In Comparative Example 10, 0.10% Fe.sub.2O.sub.3 is contained, and the content of SiO.sub.2 is 57.90%. Compared with Example 3, the thermal performance and glass melting difficulty are almost the same, and the stress value and stress depth after two-step tempering are basically the same. And the bending strength and the falling ball energy withstanding are slightly reduced, but the color is obviously yellow, which is not conducive to the application in the display cover industries, so it should be avoided as much as possible.

[0122] In the reinforcement step of Comparative Example 11, only the first step of reinforcement is carried out. Compared with Example 4, since Na—K ion exchange and a large amount of Li—K ion exchange could not be carried out during the tempering process, only Li— Na exchange and a small amount of Li—K exchange exist on the surface, and the stress value of the glass surface is only 386 MPa. Since the second exchange is not carried out, the total stress depth Dol0 (μm) is also 20 μm-30 μm lower than that of Example 4, resulting in the bending strength of the glass being only 524 MPa, and the falling ball energy withstanding being less than 0.2 J.

[0123] In the reinforcement step of Comparative Example 12, only the second step of reinforcement is carried out. Compared with Example 5, since Li—Na ion exchange could not be carried out during the tempering process, only Li—K and Na—K exchanges are carried out, the glass surface has higher compressive stress value, but the stress depth is only about 5.4 μm, its CS10, CS30, and CS100 are all 0, and Dol0 (μm) is only 5.4 μm, which is much lower than the average level of more than 100 microns in the secondary reinforcement, resulting in the bending strength being only 489 MPa, and the falling ball energy withstanding being less than 0.2 J.

[0124] In the reinforcement step of Comparative Example 13, the ratio of sodium nitrate and potassium nitrate is not within the range required herein. As a result, the Li—Na exchange and part of the Na—K and Li—K exchanges in the first step of tempering during the tempering process are not optimal, and the main Na—K ion exchange in the second step of tempering is also at a relatively low level, and its various tempering data are far lower than those of Example 6, which directly leads to a great reduction in its bending strength and falling ball energy withstanding.

TABLE-US-00005 TABLE 5 Composition and performance data of the lithium-zirconium- based aluminosilicate glass of Comparative Examples 8 to 13 Comparative Comparative Comparative Comparative Comparative Comparative Composition (%) Example 8 Example 9 Example 10 Example 11 Example 12 Example 13 SiO.sub.2 50.00 54.50 57.90 59.00 63.00 72.00 Al.sub.2O.sub.3 26.00 18.00 22.00 18.00 14.00 12.00 B.sub.2O.sub.3 0.10 — 1.50 2.50 10.00 1.00 Li.sub.2O 2.00 6.00 3.50 6.00 4.00 6.00 Na.sub.2O 7.00 8.50 6.00 7.00 4.00 6.00 K.sub.2O — — 1.00 1.50 4.00 0.50 MgO 6.00 5.00 1.00 1.00 — 1.00 CaO — 4.00 — — — — SrO — — 4.00 — — — ZnO — — — 4.00 — — ZrO.sub.2 5.00 4.00 3.00 1.00 1.00 0.50 TiO.sub.2 2.00 — — — — — SnO.sub.2 0.40 — — — — 1.00 CeO.sub.2 0.50 — — — — — P.sub.2O.sub.5 1.00 — — — — — Fe.sub.2O.sub.3 — — 0.10 — — — Li.sub.2O + Na.sub.2O + K.sub.2O 9 14.5 10.5 14.5 12 12.5 Li.sub.2O/(Li.sub.2O + Na.sub.2O + K.sub.2O) 0.22 0.41 0.33 0.41 0.33 0.48 Al.sub.2O.sub.3 + ZrO.sub.2 32 22 25 19 15 12.5 Coefficient of thermal 95.3 91.2 85.6 89.3 90.1 84.5 expansion CTE (20° C.~300° C., ×10.sup.−7) Glass transition point 582 567 534 512 504 536 temperature T.sub.g (° C.) Expansion softening point 630 618 593 574 559 598 temperature T.sub.s (° C.) T.sub.2 (η viscosity, logη = 2, ° C.) 1632 1615 1592 1572 1567 1597 T.sub.3 (η viscosity, logη = 3, ° C.) 1374 1333 1322 1282 1268 1320 T.sub.4 (η viscosity, logη = 4, ° C.) 1171 1149 1125 1083 1069 1129 T.sub.5 (η viscosity, logη = 5, ° C.) 1052 1033 988 966 954 994 CS0(MPa) 934 914 998 386 865 643 CS10(MPa) 291 262 334 225 0 134 CS30(MPa) 145 158 205 148 0 92 CS100(MPa) 89 64 96 79 0 32 Dol0(μm) 204 154 187 135 5.4 85 Dol600(μm) 8.2 5.8 6.9 0 1.8 4.2 Bending strength (MPa) 758 682 843 524 489 624 Impact energy 0.320 0.320 0.480 <0.200 <0.200 0.240 withstanding (J) Color of glass White White Yellow White White White

[0125] It can be seen from the above experimental results that the reinforced glasses obtained by subjecting the lithium-zirconium-based aluminosilicate glasses prepared in Examples 1 to 21 to a two-step reinforcement treatment have a surface compressive stress CS0 greater than 800 MPa, a compressive stress CS10 still exceeding 230 MPa at a depth of 10 μm from the glass surface, a compressive stress CS30 exceeding 140 MPa at a depth of 30 μm from the surface, and a stress depth Dol0 greater than 150 μm when the composite compressive stress produced by ion exchange drops to 0 MPa (the detection limit of the instrument). And the reinforced glasses have a bending strength of greater than 700 MPa, and can withstand a falling ball energy greater than 0.4 J.

[0126] Each of the technical features of the above-mentioned embodiments may be combined arbitrarily. To simplify the description, not all the possible combinations of each of the technical features in the above embodiments are described. However, all of the combinations of these technical features should be considered as within the scope of this disclosure, as long as such combinations do not contradict with each other.

[0127] The above-mentioned embodiments are merely illustrative of several embodiments of the present disclosure, which are described specifically and in detail, but it cannot be understood to limit the scope of the present disclosure. It should be noted that, for those ordinary skilled in the art, several variations and improvements may be made without departing from the concept of the present disclosure, and all of which are within the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure shall be defined by the appended claims.