High-crystallinity transparent lithium aluminosilicate glass-ceramic and preparation method therefor

Abstract

Disclosed in the present invention are a high-crystallinity transparent lithium aluminosilicate glass-ceramic and a preparation method therefor. The lithium aluminosilicate glass-ceramic comprises the following oxide components in percentages by mole: 63-74% of SiO2, 3-10% of Al2O3, 12-21% of Li2O, 0.5-4% of MgO, 1-4% of ZrO2, 0.5-4% of P2O5, 0.1-2% of Sb2O3, 1-4% of Na2O, and 0.1-2% of K2O. The main crystalline phase of the lithium aluminosilicate glass-ceramic prepared in the present invention is LiAlSi4O10, the glass-ceramic is transparent and has excellent mechanical properties, and the size of crystals in the glass-ceramic is within 100 nm and the degree of crystallinity reaches 80% or more by using a composite nucleating agent of ZrO2 and P2O5, and by regulating and controlling the composition of oxides and a heat treatment system, thereby meeting the application requirements for cover glass of mobile terminals.

Description

A highly crystalline transparent lithium aluminum silicon microcrystalline glass and its preparation method Technical Field

[0001] This invention belongs to the field of glass preparation technology, specifically relating to a highly crystalline transparent lithium aluminum silicon microcrystalline glass and its preparation method. Background Technology

[0002] With the continuous upgrading of electronic information display equipment, people's requirements for the drop resistance and scratch resistance of cover glass used for display screens are constantly increasing. Microcrystalline glass possesses excellent mechanical properties such as high toughness and high hardness, and the preparation of microcrystalline glass that meets transparency requirements is one of the future development directions of the electronic information display industry.

[0003] For glass-ceramics to be transparent, two conditions must be met: 1. The refractive index of the crystals must not differ significantly from that of the glass phase; 2. The crystal size must be less than 100 nm. The amount of crystals directly determines the mechanical properties of glass-ceramics. Generally, the higher the crystal content, the better the mechanical properties. The key to improving the mechanical properties of glass-ceramics is to ensure that the crystal size within the glass is small while precipitating more crystals. Summary of the Invention

[0004] The purpose of this invention is to prepare a lithium aluminum silicon microcrystalline glass with high crystallinity and small crystal size, thereby improving its mechanical properties without affecting its transparency. Therefore, it is necessary to rationally control the composition, ensuring that the types of crystalline phases are such that there is no significant difference between the refractive index of the crystal phase and the refractive index of the glass phase; and by controlling the type and ratio of nucleating agents, to ensure that the crystal size is less than 100 nm while maximizing crystallization, thereby enhancing the mechanical properties of the microcrystalline glass.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] A highly crystalline transparent lithium aluminum silicon microcrystalline glass, characterized in that the microcrystalline glass is composed of oxides in the following molar percentages: SiO2: 63-74%, Al2O3: 3-10%, Li2O: 12-21%, MgO: 0.5-4%, ZrO2: 1-4%, P2O5: 0.5-4%, Sb2O3: 0.1-2%, Na2O: 1-4%, K2O: 0.1-2%;

[0007] The value of (Li2O+Al2O3) / SiO2 is 0.2 to 0.5.

[0008] The value of (Li2O+Na2O+K2O) / (SiO2+Al2O3) is 0.1 to 0.4;

[0009] The ZrO2 / P2O5 ratio is 0.2 to 0.9.

[0010] The further technical solution is as follows:

[0011] The microcrystalline glass is composed of oxides in the following molar percentages: SiO2: 66-72%, Al2O3: 4-8%, Li2O: 14-20%, MgO: 1-3%, ZrO2: 1-4%, P2O5: 0.5-3%, Sb2O3: 0.1-1%, Na2O: 1-3%, K2O: 0.1-1%.

[0012] The value of (Li2O+Al2O3) / SiO2 is 0.2-0.4; the value of (Li2O+Na2O+K2O) / (SiO2+Al2O3) is 0.1-0.4; and the value of ZrO2 / P2O5 is 0.3-0.8.

[0013] This invention also provides a method for preparing highly crystalline transparent lithium aluminum silicon microcrystalline glass, comprising the following steps:

[0014] (1) Raw material preparation: Convert each oxide component into the introduced compound raw material according to the formula described in claim 1, 2 or 3, and mix each raw material thoroughly and evenly in a mixer for 1 to 3 hours;

[0015] (2) Melting: The mixed raw materials are loaded into a platinum crucible, and then the platinum crucible is placed in a high-temperature electric furnace. The temperature is raised to 1500-1600℃ according to the step temperature system and held for 2-4 hours to obtain clear glass melt.

[0016] (3) Molding annealing: The glass liquid is poured into a preheated copper mold and shaped. The shaped glass is quickly transferred to an annealing furnace and annealed at 450-550℃ / min for 2 hours. After annealing, the glass is cooled naturally to obtain the base glass.

[0017] (4) Heat treatment: The base glass is placed in a crystallization furnace and heated to 550-630℃ and held for 2-10 hours for nucleation. Then the temperature is raised to 660-720℃ and held for 0.5-1.5 hours for crystallization to obtain lithium aluminum silicon microcrystalline glass.

[0018] Furthermore, in step (4), the heating regime of the base glass during the nucleation stage is 5-10℃ / min, and the heating regime during the crystallization stage is 10-15℃ / min.

[0019] The highly crystalline transparent lithium aluminum silicon microcrystalline glass of the present invention has a crystallinity of over 80% and a grain size of less than 100 nm; the light transmittance of the lithium aluminum silicon microcrystalline glass at 550 nm is over 75%; and the Vickers hardness range of the lithium aluminum silicon microcrystalline glass is 6.5 to 7.4 GPa.

[0020] The principles underlying the selection of the roles and contents of each glass component in the formula in this invention are as follows:

[0021] SiO4, Al2O3, and Li2O are the basic components of lithium aluminum silicon microcrystalline glass. Referring to the SiO4—Al2O3—Li2O ternary phase diagram, LiAlSi4O 10 The crystallization content range was selected based on the content of the three components: 63-74% SiO2, 3-10% Al2O3, and 12-21% Li2O, ensuring the basic network structure and the types of precipitated crystalline phases of the glass. MgO can improve the glass's formability and reduce the crystallization rate, preventing excessively rapid crystal growth and large crystal size. In this invention, the molar percentage of MgO is 0.5-4%. Sb2O3 acts as a clarifying agent, effectively preventing the formation of bubbles during the glass melting process. In this invention, 0.1-2% Sb2O3 is the most effective. The introduction of Na2O and K2O can regulate the glass network and provide conditions for subsequent strengthening of the glass-ceramic. In this invention, 1-4% Na2O and 0.1-2% K2O are the most effective. ZrO2 and P2O5 are used as nucleating agents. ZrO2 primarily precipitates ZrO2-rich micro-inhomogeneous regions in the glass matrix first, then induces glass nucleation and crystal growth on these regions. ZrO2, as a nucleating agent, does not color the glass; however, its solubility in glass is limited, and it has a high melting point. In this invention, 1–4% ZrO2 yields the best results. P2O5 is used as a nucleating agent because P… 5+ The ions have a relatively strong electric field and readily react with R. + Or R 2+ Ions are separated from the glass network together, promoting glass phase separation, reducing interfacial energy and nucleation activation energy, and promoting crystal precipitation. In this invention, 0.5-4% P2O5 has the best effect.

[0022] Compared with the prior art, the present invention has the following advantages:

[0023] 1. By adjusting the ratio of three oxides, SiO2, Al2O3, and Li2O, the crystalline phase precipitated in lithium aluminum silicon glass can ensure the transparency of the glass.

[0024] 2. By using ZrO2 and P2O5 composite nucleating agents and adjusting the ratio of ZrO2 and P2O5, combined with a specific heat treatment process, the crystal size inside the lithium aluminum silicon microcrystalline glass is kept within 100 nm and the crystallinity reaches 80%.

[0025] 3. The prepared lithium aluminum silicon microcrystalline glass achieves a Vickers hardness of 712 GPa and a flexural strength of 608 MPa while ensuring a transmittance of 80%, which can meet the application requirements of high-strength wear-resistant mobile terminal glass. Attached Figure Description

[0026] Figure 1 shows the X-ray diffraction (XRD) pattern of the microcrystalline glass prepared in Example 7;

[0027] Figure 2 is a scanning electron microscope (SEM) image of the microcrystalline glass prepared in Example 7. Detailed Implementation

[0028] To better understand the present invention, the following embodiments further illustrate the content of the present invention, but the content of the present invention is not limited to the following embodiments.

[0029] The base glass and glass-ceramics of Examples 1-12 can be prepared by the following method:

[0030] (1) Raw material preparation: Add each raw material formula to the mixer according to the component ratio in Table 1 and mix thoroughly for 2 hours;

[0031] (2) Melting: The mixed raw materials are loaded into a platinum crucible, and then the platinum crucible is placed in a high-temperature electric furnace. First, the temperature is raised from room temperature to 800℃ at 5℃ / min, then from 800℃ to 1300℃ at 3℃ / min, and then from 1300℃ to 1560℃ at 2℃ / min. The temperature is then maintained for 2 hours to obtain a clear glass melt.

[0032] (3) Molding annealing: The molten glass is poured into a copper mold preheated at 600℃ for 2 hours to form the glass. Then the formed glass is quickly transferred to an annealing furnace and annealed at 500℃ for 2 hours. After annealing, the glass is cooled naturally to obtain the base glass.

[0033] (4) Heat treatment: The base glass is placed in a crystallization furnace and heated to 570°C at 8°C / min. It is kept at this temperature for 8 hours to nucleate. After nucleation, the temperature is increased to 680°C at 15°C / min and kept at this temperature for 1 hour to crystallize, thus obtaining lithium aluminum silicon microcrystalline glass.

[0034] Crystallinity, crystal size, transmittance, Vickers hardness, and flexural strength of lithium aluminum silicon glass were tested. Crystallinity was determined by calculating the proportion of diffraction intensity of the crystalline phase using XRD test data. Crystal size and distribution were calculated using a Nano Measurer based on SEM test data. Transmittance was tested on glass samples in the wavelength range of 200-1200 nm. The Vickers hardness test was performed with a loading pressure of 1.96 N and a loading time of 15 s. The flexural strength test was conducted using a four-point bending test with an upper span of 20 mm and a lower span of 40 mm.

[0035] Table 1

[0036] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any person skilled in the art can make many possible variations and modifications to the technical solutions of the present invention, or modify them into equivalent embodiments, without departing from the scope of the present invention. Therefore, any simple modifications, equivalent substitutions, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention, without departing from the scope of the present invention, shall still fall within the protection scope of the present invention.

Claims

1. A highly crystalline, transparent lithium aluminum silicon microcrystalline glass, characterized in that, The microcrystalline glass is composed of oxides in the following molar percentages: SiO2: 63-74%, Al2O3: 3-10%, Li2O: 12-21%, MgO: 0.5-4%, ZrO2: 1-4%, P2O5: 0.5-4%, Sb2O3: 0.1-2%, Na2O: 1-4%, K2O: 0.1-2%; The value of (Li2O+Al2O3) / SiO2 is 0.2 to 0.

5. The value of (Li2O+Na2O+K2O) / (SiO2+Al2O3) is 0.1 to 0.4; The ZrO2 / P2O5 ratio is 0.2 to 0.

9.

2. The highly crystalline transparent lithium aluminum silicon microcrystalline glass according to claim 1, characterized in that, The microcrystalline glass is composed of oxides in the following molar percentages: SiO2: 66-72%, Al2O3: 4-8%, Li2O: 14-20%, MgO: 1-3%, ZrO2: 1-4%, P2O5: 0.5-3%, Sb2O3: 0.1-1%, Na2O: 1-3%, K2O: 0.1-1%.

3. The highly crystalline transparent lithium aluminum silicon microcrystalline glass according to claim 1, characterized in that, The value of (Li2O+Al2O3) / SiO2 is 0.2-0.4; the value of (Li2O+Na2O+K2O) / (SiO2+Al2O3) is 0.1-0.4; and the value of ZrO2 / P2O5 is 0.3-0.

8.

4. The method for preparing a highly crystalline transparent lithium aluminum silicon microcrystalline glass according to claims 1-3, characterized in that... Includes the following steps: (1) Raw material preparation: Convert each oxide component into the introduced compound raw material according to the formula described in claim 1, 2 or 3, and mix each raw material thoroughly and evenly in a mixer for 1 to 3 hours; (2) Melting: The mixed raw materials are loaded into a platinum crucible, and then the platinum crucible is placed in a high-temperature electric furnace. The temperature is raised to 1500-1600℃ according to the step temperature system and held for 2-4 hours to obtain clear glass melt. (3) Molding annealing: The glass liquid is poured into a preheated copper mold and shaped. The shaped glass is quickly transferred to an annealing furnace and annealed at 450-550℃ / min for 2 hours. After annealing, the glass is cooled naturally to obtain the base glass. (4) Heat treatment: The base glass is placed in a crystallization furnace and heated to 550-630℃ and held for 2-10 hours for nucleation. Then the temperature is raised to 660-720℃ and held for 0.5-1.5 hours for crystallization to obtain lithium aluminum silicon microcrystalline glass.

5. The method for preparing a highly crystalline transparent lithium aluminum silicon microcrystalline glass according to claim 4, characterized in that, In step (4), the heating regime of the base glass during the nucleation stage is 5-10℃ / min, and the heating regime during the crystallization stage is 10-15℃ / min.

6. The highly crystalline transparent lithium aluminum silicon microcrystalline glass according to claim 5, characterized in that, The highly crystalline transparent lithium aluminum silicon microcrystalline glass has a crystallinity of over 80% and a grain size of less than 100 nm; the light transmittance of the lithium aluminum silicon microcrystalline glass at 550 nm is over 75%; and the Vickers hardness range of the lithium aluminum silicon microcrystalline glass is 6.5 to 7.4 GPa.

Images