Glass ceramic and preparation method thereof

Abstract

The invention discloses microcrystalline glass and a preparation method thereof, the microcrystalline glass is composed of 70-80 wt% of a crystal phase and 20-30 wt% of a glass phase, and the crystal phase is lithium disilicate and petalite. According to the invention, the crystal content and proportion of lithium disilicate and petalite separated out in the material are strictly controlled through a reasonable crystallization process, and the microcrystalline glass with more glass phase components is prepared on the basis of ensuring the performance of the microcrystalline glass through reasonable adjustment of a production process; and the processing difficulty of the hot bending process of a cover plate factory can be reduced due to the increase of the glass phase of the prepared product, so that the production cost is further reduced.

Description

Technical Field

[0001] This invention belongs to the field of inorganic new materials, specifically relating to a microcrystalline glass and its preparation method. Background Technology

[0002] Glass-ceramics, also known as glass-ceramics, are polycrystalline solid-phase materials containing glass particles, produced by controlled nucleation and crystallization of base glasses with specific compositions at certain temperatures. The properties of glass-ceramics are primarily determined by their main crystalline phase, which can be controlled through nucleation, crystallization, and the selection of different parent glass components. Glass-ceramics combine the characteristics of both glass and ceramics, exhibiting advantages such as high strength, good wear resistance, and strong corrosion resistance. They outperform metals and polymers in thermal, chemical, biological, optical, and electrical properties, and can be widely used in building materials, pipes, pumps, bearings, and other corrosion-resistant or wear-resistant applications.

[0003] Glass-ceramics are classified into silicate glass-ceramics, aluminosilicate glass-ceramics, fluorosilicate glass-ceramics, borate glass-ceramics, and phosphate glass-ceramics based on their glass systems. Among these, aluminosilicate glass-ceramics have become a research hotspot due to their significant performance advantages. Aluminosilicate glass-ceramics mainly belong to four major systems: Li₂O-Al₂O₃-SiO₂ system, MgO-Al₂O₃-SiO₂ system, Na₂O-Al₂O₃-SiO₂ system, and ZnO-Al₂O₃-SiO₂ system. Among these, Li₂O-Al₂O₃-SiO₂ (LAS) glass-ceramics are characterized by high strength, low coefficient of thermal expansion, and chemical stability, making them an important class of aluminosilicate glass-ceramics. In the preparation of LAS glass-ceramics, the composition of the base glass is a key factor determining the type of precipitated crystalline phase and crystallization ability, which can influence the material's properties through its internal structure. Therefore, it is essential to select a suitable material as the main crystalline phase of the glass-ceramic, so that the resulting glass-ceramic has high resistance to deformation, hardness, corrosion resistance, acid and alkali resistance and heat resistance. Summary of the Invention

[0004] To overcome the shortcomings of existing technologies, and while ensuring the inherent properties of the microcrystalline glass, this invention adjusts the raw material formulation and production process to reduce production costs and improve production efficiency. The specific technical solution is as follows: The first solution provided by the present invention is: a microcrystalline glass, which is composed of 70-80 wt% crystalline phase and 20-30 wt% glass phase, wherein the crystalline phase is lithium disilicate and lithium feldspar, and the raw material composition of the microcrystalline glass is: 70-74 wt% SiO2, 6-7.5 wt% Al2O3, 10-12 wt% Li2O, 3.5-6 wt% ZrO2, 2-2.4 wt% P2O5, 0.8-1.6 wt% Na2O and 0.06 wt% Sb2O3.

[0005] The mass ratio of lithium disilicate to petalite is 0.95-1.33. Further, the mass ratio of lithium disilicate to petalite can be any value between 0.95, 1, 1.05, 1.1, 1.15, 1.2, 1.25, 1.3, and 1.33; further, the lithium disilicate accounts for 35-42 wt% of the total glass-ceramic, and the petalite accounts for 37-40 wt% of the total glass-ceramic. Even further, the lithium disilicate accounts for any value between 35 wt%, 36 wt%, 37 wt%, 38 wt%, 39 wt%, 40 wt%, 41 wt%, and 42 wt% of the total glass-ceramic, or any value between two values; the petalite accounts for any value between 37 wt%, 38 wt%, 39 wt%, and 40 wt% of the total glass-ceramic, or any value between two values.

[0006] The raw material composition of the microcrystalline glass also includes: 0-2wt% K2O, 0-0.02wt% CaO, 0-0.02wt% BaO, 0-0.08wt% HfO2, 0-2wt% TiO2 and 0-0.05wt% Y2O3.

[0007] Preferably, the raw materials of the microcrystalline glass contain 1.1-2 wt% K2O, 0.01-0.02 wt% CaO, 0.01-0.02 wt% BaO, 0.06-0.08 wt% HfO2, 0.5-2 wt% TiO2 and 0.02-0.05 wt% Y2O3.

[0008] Furthermore, the mass ratio of Na2O / (Na2O+Li2O+K2O+Sb2O3) in the microcrystalline glass raw material is 0.04-0.13. Furthermore, the mass ratio of Na2O / (Na2O+Li2O+K2O+Sb2O3) of 0.04-0.13 is any value from 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.1, 0.11, 0.12, to 0.13, or any value between two such values.

[0009] The average size of the microcrystalline glass grains is 10-30 nm. Further, the average size of the microcrystalline glass grains can be any value between 10 nm, 15 nm, 20 nm, 25 nm, and 30 nm.

[0010] The surface CS of the microcrystalline glass is ≥450 MPa, CT is ≥85 MPa, and Dol is ≥95 µm. Further, the surface CS of the microcrystalline glass is any value between two points of 450 MPa, 500 MPa, 550 MPa, 600 MPa, and 650 MPa; the CT value of the microcrystalline glass is any value between two points of 85 MPa, 90 MPa, 95 MPa, 100 MPa, 105 MPa, 110 MPa, 115 MPa, 120 MPa, 125 MPa, and 130 MPa; and the Dol value of the microcrystalline glass is any value between two points of 95 µm, 100 µm, 105 µm, 110 µm, 115 µm, 120 µm, 125 µm, and 130 µm.

[0011] The present invention also provides a method for preparing the microcrystalline glass in the first embodiment, comprising the following steps: Step 1: Place 70-74wt% SiO2, 6-7.5wt% Al2O3, 10-12wt% Li2O, 3.5-6wt% ZrO2, 2-2.4wt% P2O5, 0.8-1.6wt% Na2O and 0.06wt% Sb2O3 in a crucible and melt them at 1500-1600℃; Step 2: The molten liquid obtained in Step 1 is used to form a base glass plate of a certain thickness through ingot cutting and rolling. Step 3: For the obtained base glass plate, in order to carry out nucleation and crystal growth, heat treatment is performed. The heat treatment process is to first treat at 560-580℃ for 4 hours, then treat at 740-750℃ for 1-4 hours, and then perform hot bending treatment. The hot bending treatment process is to bend at 760-780℃ for 60-80 seconds to obtain the microcrystalline glass.

[0012] Preferably, the preparation method further includes step 4, which involves strengthening the obtained microcrystalline glass. The specific strengthening process is as follows: the first strengthening is carried out at 470-510℃, with ion exchange in the first strengthening solution for 2-8 hours; the second strengthening is carried out at 470℃, with ion exchange in the second strengthening solution for 1-4 hours.

[0013] Furthermore, the first strengthening liquid is composed of a basic molten salt of potassium salt and sodium salt in a mass ratio of 60:40 and a lithium salt of 0.2% by mass of the basic molten salt; the second strengthening liquid is composed of pure potassium molten salt.

[0014] This invention adjusts the composition of Na2O in the raw materials and its relationship with other components, and strictly controls the content and proportion of lithium disilicate and lithite crystals precipitated in the material through a reasonable crystallization process. By reasonably adjusting the production process, a microcrystalline glass with a higher glass phase content is obtained while ensuring the performance of the microcrystalline glass. The increased glass phase in the product obtained by the above method can reduce the processing difficulty of the hot bending process in the cover plate factory, thereby further reducing the production cost.

[0015] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, the preferred embodiments of the present invention are described in detail below. Attached Figure Description

[0016] Figure 1 The image shows the XRD pattern of the microcrystalline glass prepared in Example 1 of this invention. Figure 2 The image shows the XRD pattern of the microcrystalline glass prepared in Comparative Example 1 of this invention. Detailed Implementation

[0017] To make the technical means, creative features, objectives and effects of this invention easier to understand, the technical solutions in the embodiments of this invention will be clearly and completely described below in conjunction with the embodiments of this invention. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments.

[0018] Example 1

[0019] This embodiment provides a microcrystalline glass, which is composed of 80 wt% crystalline phase and 20 wt% glass phase, such as... Figure 1 As shown, the crystalline phase consists of 42 wt% lithium disilicate and 38 wt% lithium feldspar, which constitute the entire glass-ceramic structure. By mass fraction, the raw material composition of the glass-ceramic is: 70.5 wt% SiO2, 6.8 wt% Al2O3, 11.62 wt% Li2O, 6 wt% ZrO2, 2.1 wt% P2O5, 0.9 wt% Na2O, 2 wt% K2O, 0.02 wt% BaO, and 0.06 wt% Sb2O3.

[0020] This embodiment also provides a method for preparing the microcrystalline glass, the specific preparation method is as follows: Step 1: Place 70.5wt% SiO2, 6.8wt% Al2O3, 11.62wt% Li2O, 6wt% ZrO2, 2.1wt% P2O5, 0.9wt% Na2O, 2wt% K2O, 0.02wt% BaO and 0.06wt% Sb2O3 in a crucible and melt them at 1500-1600℃; Step 2: The molten liquid obtained in Step 1 is used to form a base glass plate of a certain thickness through ingot cutting and rolling. Step 3: For the obtained base glass plate, in order to carry out nucleation and crystal growth, heat treatment is performed. The heat treatment process is to first treat at 560°C for 4 hours, then treat at 740°C for 1 hour, and then perform hot bending treatment. The hot bending treatment process is to bend at 780°C for 80 seconds to obtain the microcrystalline glass.

[0021] The preparation method further includes step 4, which involves strengthening the obtained microcrystalline glass. The specific strengthening process is as follows: the first strengthening is carried out at 480°C with ion exchange in the first strengthening solution for 7 hours; the second strengthening is carried out at 470°C with ion exchange in the second strengthening solution for 4 hours.

[0022] Furthermore, the first strengthening liquid is composed of a basic molten salt of potassium salt and sodium salt in a mass ratio of 60:40 and a lithium salt of 0.2% by mass of the basic molten salt; the second strengthening liquid is composed of pure potassium molten salt.

[0023] The fracture toughness of the microcrystalline glass prepared in this embodiment was tested to be 1.12 MPa / m. 2 After the first chemical strengthening process, at a thickness of 0.6 mm, the surface CS is 256 MPa, CT is 134 MPa, and Dol is 119 µm. After the second chemical strengthening process, the surface CS is 650 MPa, CT is 126 MPa, and Dol is 114 µm. The average grain size in the glass-ceramic is 28 nm, and at a thickness of 0.6 mm, the transmittance of visible light is 90.5%.

[0024] Example 2

[0025] This embodiment provides a microcrystalline glass, which is composed of 79 wt% crystalline phase and 21 wt% glass phase. The crystalline phase consists of 39 wt% lithium disilicate and 40 wt% lithium feldspar, accounting for the entire microcrystalline glass. By mass fraction, the raw material composition of the microcrystalline glass is: 73.8 wt% SiO2, 7.5 wt% Al2O3, 11.2 wt% Li2O, 3.6 wt% ZrO2, 2.2 wt% P2O5, 1.6 wt% Na2O, 0.02 wt% CaO, 0.02 wt% Y2O3 and 0.06 wt% Sb2O3.

[0026] This embodiment also provides a method for preparing the microcrystalline glass, the specific preparation method is as follows: Step 1: Place 73.8wt% SiO2, 7.5wt% Al2O3, 11.2wt% Li2O, 3.6wt% ZrO2, 2.2wt% P2O5, 1.6wt% Na2O, 0.02wt% CaO, 0.02wt% Y2O3 and 0.06wt% Sb2O3 in a crucible and melt them at 1500-1600℃; Step 2: The molten liquid obtained in Step 1 is used to form a base glass plate of a certain thickness through ingot cutting and rolling. Step 3: For the obtained base glass plate, in order to carry out nucleation and crystal growth, heat treatment is performed. The heat treatment process is to first treat at 560°C for 4 hours, then treat at 720°C for 1 hour, and then perform hot bending treatment. The hot bending treatment process is to bend at 775°C for 75 seconds to obtain the microcrystalline glass.

[0027] The preparation method further includes step 4, which involves strengthening the obtained microcrystalline glass. The specific strengthening process is as follows: the first strengthening is carried out at 485°C with ion exchange in the first strengthening solution for 6 hours; the second strengthening is carried out at 470°C with ion exchange in the second strengthening solution for 3 hours.

[0028] Furthermore, the first strengthening liquid is composed of a basic molten salt of potassium salt and sodium salt in a mass ratio of 60:40 and a lithium salt of 0.2% by mass of the basic molten salt; the second strengthening liquid is composed of pure potassium molten salt.

[0029] The fracture toughness of the microcrystalline glass prepared in this embodiment was tested to be 1.21 MPa / m. 2 After the first chemical strengthening process, at a thickness of 0.6 mm, the surface CS is 271 MPa, CT is 130 MPa, and Dol is 122 µm. After the second chemical strengthening process, the surface CS is 580 MPa, CT is 122 MPa, and Dol is 117 µm. The average grain size in the glass-ceramic is 30 nm, and at a thickness of 0.6 mm, the transmittance of visible light is 90%.

[0030] Example 3

[0031] This embodiment provides a microcrystalline glass, which is composed of 79 wt% crystalline phase and 21 wt% glass phase. The crystalline phase consists of 40 wt% lithium disilicate and 39 wt% lithium feldspar, accounting for 40 wt% of the total microcrystalline glass. By mass fraction, the raw material composition of the microcrystalline glass is: 71 wt% SiO2, 6.52 wt% Al2O3, 11.6 wt% Li2O, 5.7 wt% ZrO2, 2 wt% P2O5, 0.8 wt% Na2O, 1.8 wt% K2O, 0.02 wt% BaO, 0.5 wt% TiO2 and 0.06 wt% Sb2O3.

[0032] This embodiment also provides a method for preparing the microcrystalline glass, the specific preparation method is as follows: Step 1: Place 71wt% SiO2, 6.52wt% Al2O3, 11.6wt% Li2O, 5.7wt% ZrO2, 2wt% P2O5, 0.8wt% Na2O, 1.8wt% K2O, 0.02wt% BaO, 0.5wt% TiO2 and 0.06wt% Sb2O3 in a crucible and melt them at 1500-1600℃; Step 2: The molten liquid obtained in Step 1 is used to form a base glass plate of a certain thickness through ingot cutting and rolling. Step 3: For the obtained base glass plate, in order to carry out nucleation and crystal growth, heat treatment is performed. The heat treatment process is to first treat at 560°C for 4 hours, then treat at 740°C for 1 hour, and then perform hot bending treatment. The hot bending treatment process is to bend at 770°C for 70 seconds to obtain the microcrystalline glass.

[0033] The preparation method further includes step 4, which involves strengthening the obtained microcrystalline glass. The specific strengthening process is as follows: the first strengthening is carried out at 470°C with ion exchange in the first strengthening solution for 8 hours; the second strengthening is carried out at 470°C with ion exchange in the second strengthening solution for 2 hours.

[0034] Furthermore, the first strengthening liquid is composed of a basic molten salt of potassium salt and sodium salt in a mass ratio of 60:40 and a lithium salt of 0.2% by mass of the basic molten salt; the second strengthening liquid is composed of pure potassium molten salt.

[0035] The fracture toughness of the microcrystalline glass prepared in this embodiment was tested to be 1.15 MPa / m. 2After the first chemical strengthening process, at a thickness of 0.6 mm, the surface CS is 236 MPa, CT is 140 MPa, and Dol is 115 µm. After the second chemical strengthening process, the surface CS is 550 MPa, CT is 132 MPa, and Dol is 111 µm. The average grain size in the glass-ceramic is 26 nm, and at a thickness of 0.6 mm, the transmittance of visible light is 90.5%.

[0036] Example 4

[0037] This embodiment provides a microcrystalline glass, which is composed of 78 wt% crystalline phase and 22 wt% glass phase. The crystalline phase consists of 40 wt% lithium disilicate and 38 wt% lithium feldspar, accounting for 40 wt% of the total microcrystalline glass. By mass fraction, the raw material composition of the microcrystalline glass is: 71.2 wt% SiO2, 6.4 wt% Al2O3, 11.2 wt% Li2O, 5.12 wt% ZrO2, 2.1 wt% P2O5, 1.1 wt% Na2O, 1.5 wt% K2O, 0.02 wt% BaO, 1.3 wt% TiO2 and 0.06 wt% Sb2O3.

[0038] This embodiment also provides a method for preparing the microcrystalline glass, the specific preparation method is as follows: Step 1: Place 71.2wt% SiO2, 6.4wt% Al2O3, 11.2wt% Li2O, 5.12wt% ZrO2, 2.1wt% P2O5, 1.1wt% Na2O, 1.5wt% K2O, 0.02wt% BaO, 1.3wt% TiO2 and 0.06wt% Sb2O3 in a crucible and melt them at 1500-1600℃; Step 2: The molten liquid obtained in Step 1 is used to form a base glass plate of a certain thickness through ingot cutting and rolling. Step 3: For the obtained base glass plate, in order to carry out nucleation and crystal growth, heat treatment is performed. The heat treatment process is to first treat at 560°C for 4 hours, then treat at 740°C for 1 hour, and then perform hot bending treatment. The hot bending treatment process is to bend at 765°C for 70 seconds to obtain the microcrystalline glass.

[0039] The preparation method further includes step 4, which involves strengthening the obtained microcrystalline glass. The specific strengthening process is as follows: the first strengthening is carried out at 470°C with ion exchange in the first strengthening solution for 8 hours; the second strengthening is carried out at 470°C with ion exchange in the second strengthening solution for 1 hour.

[0040] Furthermore, the first strengthening liquid is composed of a basic molten salt of potassium salt and sodium salt in a mass ratio of 60:40 and a lithium salt of 0.2% by mass of the basic molten salt; the second strengthening liquid is composed of pure potassium molten salt.

[0041] The fracture toughness of the microcrystalline glass prepared in this embodiment was tested to be 1.19 MPa / m. 2 After the first chemical strengthening process, at a thickness of 0.55 mm, the surface CS is 260 MPa, CT is 143 MPa, and Dol is 117 µm. After the second chemical strengthening process, the surface CS is 520 MPa, CT is 137 MPa, and Dol is 109 µm. The average grain size in the glass-ceramic is 18 nm, and at a thickness of 0.55 mm, the transmittance of visible light is 92%.

[0042] Example 5

[0043] This embodiment provides a microcrystalline glass, which is composed of 73 wt% crystalline phase and 27 wt% glass phase. The crystalline phase consists of 36 wt% lithium disilicate and 37 wt% lithium feldspar, accounting for 36 wt% of the total microcrystalline glass. By mass fraction, the raw material composition of the microcrystalline glass is: 71.8 wt% SiO2, 6.5 wt% Al2O3, 10.6 wt% Li2O, 5.1 wt% ZrO2, 2.3 wt% P2O5, 1.3 wt% Na2O, 1.2 wt% K2O, 0.06 wt% CaO, 0.08 wt% HfO2, 1 wt% TiO2, and 0.06 wt% Sb2O3.

[0044] This embodiment also provides a method for preparing the microcrystalline glass, the specific preparation method is as follows: Step 1: Place 71.8wt% SiO2, 6.5wt% Al2O3, 10.6wt% Li2O, 5.1wt% ZrO2, 2.3wt% P2O5, 1.3wt% Na2O, 1.2wt% K2O, 0.06wt% CaO, 0.08wt% HfO2, 1wt% TiO2 and 0.06wt% Sb2O3 in a crucible and melt them at 1500-1600℃; Step 2: The molten liquid obtained in Step 1 is used to form a base glass plate of a certain thickness through ingot cutting and rolling. Step 3: For the obtained base glass plate, in order to carry out nucleation and crystal growth, heat treatment is performed. The heat treatment process is to first treat at 580°C for 4 hours, then treat at 750°C for 2 hours, and then perform hot bending treatment. The hot bending treatment process is to bend at 780°C for 80 seconds to obtain the microcrystalline glass.

[0045] The preparation method further includes step 4, which involves strengthening the obtained microcrystalline glass. The specific strengthening process is as follows: the first strengthening is carried out at 470°C with ion exchange in the first strengthening solution for 8 hours; the second strengthening is carried out at 470°C with ion exchange in the second strengthening solution for 0.5 hours.

[0046] Furthermore, the first strengthening liquid is composed of a basic molten salt of potassium salt and sodium salt in a mass ratio of 60:40 and a lithium salt of 0.2% by mass of the basic molten salt; the second strengthening liquid is composed of pure potassium molten salt.

[0047] The fracture toughness of the microcrystalline glass prepared in this embodiment was tested to be 1.11 MPa / m. 2 After the first chemical strengthening process, at a thickness of 0.5 mm, the surface CS of the glass is 286 MPa, CT is 139 MPa, and Dol is 124 µm. After the second chemical strengthening process, the surface CS is 489 MPa, CT is 133 MPa, and Dol is 120 µm. The average grain size in the glass-ceramic is 20 nm, and at a thickness of 0.5 mm, the transmittance of visible light is 92%.

[0048] Example 6

[0049] This embodiment provides a microcrystalline glass, which is composed of 72 wt% crystalline phase and 28 wt% glass phase. The crystalline phase consists of 35 wt% lithium disilicate and 37 wt% lithium feldspar, accounting for 35 wt% of the total microcrystalline glass. By mass fraction, the raw material composition of the microcrystalline glass is: 71.5 wt% SiO2, 6.5 wt% Al2O3, 10.6 wt% Li2O, 5.1 wt% ZrO2, 2.4 wt% P2O5, 1.2 wt% Na2O, 1.1 wt% K2O, 0.04 wt% CaO, 0.08 wt% HfO2, 1.4 wt% TiO2, 0.02 wt% Y2O3, and 0.06 wt% Sb2O3.

[0050] This embodiment also provides a method for preparing the microcrystalline glass, the specific preparation method is as follows: Step 1: Place 71.5wt% SiO2, 6.5wt% Al2O3, 10.6wt% Li2O, 5.1wt% ZrO2, 2.4wt% P2O5, 1.2wt% Na2O, 1.1wt% K2O, 0.04wt% CaO, 0.08wt% HfO2, 1.4wt% TiO2, 0.02wt% Y2O3 and 0.06wt% Sb2O3 in a crucible and melt them at 1500-1600℃; Step 2: The molten liquid obtained in Step 1 is used to form a base glass plate of a certain thickness through ingot cutting and rolling. Step 3: For the obtained base glass plate, in order to carry out nucleation and crystal growth, heat treatment is performed. The heat treatment process is to first treat at 580°C for 4 hours, then treat at 750°C for 3 hours, and then perform hot bending treatment. The hot bending treatment process is to bend at 760°C for 70 seconds to obtain the microcrystalline glass.

[0051] The preparation method further includes step 4, which involves strengthening the obtained microcrystalline glass. The specific strengthening process is as follows: the first strengthening is carried out at 500°C, with ion exchange in the first strengthening solution for 4 hours; the second strengthening is carried out at 470°C, with ion exchange in the second strengthening solution for 1.5 hours.

[0052] Furthermore, the first strengthening liquid is composed of a basic molten salt of potassium salt and sodium salt in a mass ratio of 60:40 and a lithium salt of 0.2% by mass of the basic molten salt; the second strengthening liquid is composed of pure potassium molten salt.

[0053] The fracture toughness of the microcrystalline glass prepared in this embodiment was tested to be 1.19 MPa / m. 2 After the first chemical strengthening process, at a thickness of 0.6 mm, the surface CS of the glass is 310 MPa, CT is 146 MPa, and Dol is 129 µm. After the second chemical strengthening process, the surface CS is 520 MPa, CT is 139 MPa, and Dol is 122 µm. The average grain size in the glass-ceramic is 22 nm, and at a thickness of 0.6 mm, the transmittance of visible light is 91.5%.

[0054] Example 7

[0055] This embodiment provides a microcrystalline glass, which is composed of 73 wt% crystalline phase and 27 wt% glass phase. The crystalline phase consists of 36 wt% lithium disilicate and 37 wt% lithium feldspar, accounting for 36 wt% of the total microcrystalline glass. By mass fraction, the raw material composition of the microcrystalline glass is: 70.8 wt% SiO2, 6.5 wt% Al2O3, 10.6 wt% Li2O, 5.1 wt% ZrO2, 2.4 wt% P2O5, 1.2 wt% Na2O, 1.2 wt% K2O, 0.02 wt% BaO, 0.08 wt% HfO2, 2 wt% TiO2, 0.04 wt% Y2O3, and 0.06 wt% Sb2O3.

[0056] This embodiment also provides a method for preparing the microcrystalline glass, the specific preparation method is as follows: Step 1: Place 70.8wt% SiO2, 6.5wt% Al2O3, 10.6wt% Li2O, 5.1wt% ZrO2, 2.4wt% P2O5, 1.2wt% Na2O, 1.2wt% K2O, 0.02wt% BaO, 0.08wt% HfO2, 2wt% TiO2, 0.04wt% Y2O3 and 0.06wt% Sb2O3 in a crucible and melt them at 1500-1600℃; Step 2: The molten liquid obtained in Step 1 is used to form a base glass plate of a certain thickness through ingot cutting and rolling. Step 3: For the obtained base glass plate, in order to carry out nucleation and crystal growth, heat treatment is performed. The heat treatment process is to first treat at 580°C for 4 hours, then treat at 750°C for 4 hours, and then perform hot bending treatment. The hot bending treatment process is to bend at 765°C for 65 seconds to obtain the microcrystalline glass.

[0057] The preparation method further includes step 4, which involves strengthening the obtained microcrystalline glass. The specific strengthening process is as follows: the first strengthening is carried out at 510°C with ion exchange in the first strengthening solution for 2 hours; the second strengthening is carried out at 470°C with ion exchange in the second strengthening solution for 2 hours.

[0058] Furthermore, the first strengthening liquid is composed of a basic molten salt of potassium salt and sodium salt in a mass ratio of 60:40 and a lithium salt of 0.2% by mass of the basic molten salt; the second strengthening liquid is composed of pure potassium molten salt.

[0059] The fracture toughness of the microcrystalline glass prepared in this embodiment was tested to be 1.18 MPa / m. 2 After the first chemical strengthening process, at a thickness of 0.6 mm, the surface CS of the glass is 341 MPa, CT is 157 MPa, and Dol is 121 µm. After the second chemical strengthening process, the surface CS is 610 MPa, CT is 152 MPa, and Dol is 117 µm. The average grain size in the glass-ceramic is 16 nm, and at a thickness of 0.6 mm, the transmittance of visible light is 92%.

[0060] Comparative Example 1 This comparative example provides a microcrystalline glass, such as Figure 2As shown, the glass-ceramic is composed of 77 wt% crystalline phase and 23 wt% glass phase. The crystalline phase consists of 38 wt% lithium disilicate, 28 wt% litharge, and 11 wt% lithium silicate, accounting for a total of 11 wt% of the glass-ceramic. By mass fraction, the raw material composition of the glass-ceramic is: 70.5 wt% SiO2, 6.8 wt% Al2O3, 11.5 wt% Li2O, 6 wt% ZrO2, 2.2 wt% P2O5, 2 wt% Na2O, 0.02 wt% CaO, 0.9 wt% K2O, 0.02 wt% BaO, and 0.06 wt% Sb2O3.

[0061] This comparative example also provides a method for preparing the microcrystalline glass, the specific preparation method of which is as follows: Step 1: Place 70.5wt% SiO2, 6.8wt% Al2O3, 11.5wt% Li2O, 6wt% ZrO2, 2.2wt% P2O5, 2wt% Na2O, 0.02wt% CaO, 0.9wt% K2O, 0.02wt% BaO and 0.06wt% Sb2O3 in a crucible and melt them at 1500-1600℃; Step 2: The molten liquid obtained in Step 1 is used to form a base glass plate of a certain thickness through ingot cutting and rolling. Step 3: For the obtained base glass plate, in order to carry out nucleation and crystal growth, heat treatment is performed. The heat treatment process is to first treat at 560°C for 4 hours, then treat at 740°C for 1 hour, and then perform hot bending treatment. The hot bending treatment process is to bend at 780°C for 80 seconds to obtain the microcrystalline glass.

[0062] The preparation method further includes step 4, which involves strengthening the obtained microcrystalline glass. The specific strengthening process is as follows: the first strengthening is carried out at 480°C with ion exchange in the first strengthening solution for 7 hours; the second strengthening is carried out at 470°C with ion exchange in the second strengthening solution for 4 hours.

[0063] Furthermore, the first strengthening liquid is composed of a basic molten salt of potassium salt and sodium salt in a mass ratio of 60:40 and a lithium salt of 0.2% by mass of the basic molten salt; the second strengthening liquid is composed of pure potassium molten salt.

[0064] The fracture toughness of the microcrystalline glass prepared in this comparative example was tested to be 1.1 MPa / m. 2After the first chemical strengthening process, at a thickness of 0.6 mm, the glass surface CS is 220 MPa, CT is 120 MPa, and Dol is 105 µm. After the second chemical strengthening process, the glass surface CS is 450 MPa, CT is 114 MPa, and Dol is 100 µm. The average grain size in the glass-ceramic is 40 nm, and at a thickness of 0.6 mm, the transmittance of visible light is 85%.

[0065] Comparative Example 2 This comparative example provides a glass-ceramic composed of 83 wt% crystalline phase and 27 wt% glass phase, wherein the crystalline phase is quartz crystal phase and lithium disilicate, and the raw material composition of the glass-ceramic, by mass fraction, is: 71.9 wt% SiO2, 9 wt% Al2O3, 10 wt% Li2O, 2.2 wt% ZrO2, 1.9 wt% P2O5, 0.5 wt% Na2O, 1 wt% K2O, 1 wt% MgO and 2.5 wt% ZnO.

[0066] This comparative example also provides a method for preparing the microcrystalline glass, the specific preparation method of which is as follows: Step 1: Place 71.9wt% SiO2, 9wt% Al2O3, 10wt% Li2O, 2.2wt% ZrO2, 1.9wt% P2O5, 0.5wt% Na2O, 1wt% K2O, 1wt% MgO and 2.5wt% ZnO in a crucible and melt them at 1500-1600℃; Step 2: The molten liquid obtained in Step 1 is used to form a base glass plate of a certain thickness through ingot cutting and rolling. Step 3: For the obtained base glass plate, in order to carry out nucleation and crystal growth, heat treatment is performed. The heat treatment process is to first treat at 510°C for 4 hours, then treat at 715°C for 4 hours, and then perform hot bending treatment. The hot bending treatment process is to bend at 760°C for 60 seconds to obtain the microcrystalline glass.

[0067] The preparation method further includes step 4, which involves strengthening the obtained microcrystalline glass. The specific strengthening process is as follows: the first strengthening is carried out at 460°C with ion exchange in the first strengthening solution for 10 hours; the second strengthening is carried out at 480°C with ion exchange in the second strengthening solution for 2 hours.

[0068] Furthermore, the first strengthening liquid is composed of a basic molten salt of potassium salt and sodium salt in a mass ratio of 60:40 and a lithium salt of 0.2% by mass of the basic molten salt; the second strengthening liquid is composed of pure potassium molten salt.

[0069] The fracture toughness of the microcrystalline glass prepared in this comparative example was tested to be 1.05 MPa / m. 2After the first chemical strengthening process, at a thickness of 0.55 mm, the surface CS is 210 MPa, CT is 115 MPa, and Dol is 101 µm. After the second chemical strengthening process, the surface CS is 420 MPa, CT is 110 MPa, and Dol is 96 µm. The average grain size in the glass-ceramic is 35 nm, and at a thickness of 0.55 mm, the transmittance of visible light is 90.5%.

[0070] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the methods and techniques disclosed above without departing from the scope of the present invention to create equivalent embodiments. Any simple modifications, equivalent changes and alterations 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 scope of the present invention.

Claims

1. A microcrystalline glass, characterized in that, It consists of 70-80 wt% crystalline phase and 20-30 wt% glassy phase, wherein the crystalline phase is lithium disilicate and lithium feldspar, and the raw material composition of the microcrystalline glass is: 70-74 wt% SiO2, 6-7.5 wt% Al2O3, 10-12 wt% Li2O, 3.5-6 wt% ZrO2, 2-2.4 wt% P2O5, 0.8-1.6 wt% Na2O and 0.06 wt% Sb2O3.

2. The microcrystalline glass according to claim 1, characterized in that, The mass ratio of lithium disilicate to petalite is 0.95-1.

33.

3. The microcrystalline glass according to claim 1, characterized in that, The raw material composition of the microcrystalline glass also includes: 0-2wt% K2O, 0-0.02wt% CaO, 0-0.02wt% BaO, 0-0.08wt% HfO2, 0-2wt% TiO2 and 0-0.05wt% Y2O3.

4. The microcrystalline glass according to claim 3, characterized in that, The raw materials for the microcrystalline glass contain 1.1-2 wt% K2O, 0.01-0.02 wt% CaO, 0.01-0.02 wt% BaO, 0.06-0.08 wt% HfO2, 0.5-2 wt% TiO2 and 0.02-0.05 wt% Y2O3.

5. The microcrystalline glass according to claim 1 or 3, characterized in that, The mass ratio of Na2O to (Na2O+Li2O+K2O+Sb2O3) in the microcrystalline glass raw material is 0.04-0.

13.

6. The microcrystalline glass according to any one of claims 1-3, characterized in that, The average size of the microcrystalline glass grains is 10-30 nm.

7. The microcrystalline glass according to claim 5, characterized in that, The surface of the microcrystalline glass has CS≥450Mpa, CT≥85Mpa, and Dol≥95µm.

8. A method for preparing microcrystalline glass, characterized in that, Includes the following steps: Step 1: Place 70-74wt% SiO2, 6-7.5wt% Al2O3, 10-12wt% Li2O, 3.5-6wt% ZrO2, 2-2.4wt% P2O5, 0.8-1.6wt% Na2O and 0.06wt% Sb2O3 in a crucible and melt them. Step 2: The molten liquid obtained in Step 1 is used to form a base glass plate of a certain thickness through ingot cutting and rolling. Step 3: For the obtained base glass plate, in order to carry out nucleation and crystal growth, heat treatment is performed. The heat treatment process is to first treat at 560-580℃ for 4 hours, then treat at 740-750℃ for 1-4 hours, and then perform hot bending treatment. The hot bending treatment process is to bend at 760-780℃ for 60-80 seconds to obtain the microcrystalline glass.

9. The method for preparing microcrystalline glass according to claim 8, characterized in that, The preparation method further includes step 4, which involves strengthening the obtained microcrystalline glass. The specific strengthening process is as follows: the first strengthening is carried out at 470-510℃, with ion exchange in the first strengthening solution for 2-8 hours; the second strengthening is carried out at 470℃, with ion exchange in the second strengthening solution for 1-4 hours.

10. The method for preparing microcrystalline glass according to claim 9, characterized in that, The first strengthening liquid is composed of a basic molten salt of potassium salt and sodium salt in a mass ratio of 60:40 and a lithium salt of 0.2% by mass of the basic molten salt; the second strengthening liquid is composed of pure potassium molten salt.

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