Multiphase ceramic and preparation method and application thereof

Abstract

The invention discloses a preparation method of composite ceramic, which comprises the following steps: crystallizing eucryptite base glass to prepare eucryptite microcrystalline glass; mixing the base material with eucryptite microcrystalline glass to prepare mixed slurry; sintering the mixed slurry to prepare multiphase ceramic; the temperature of crystallization and the temperature of sintering differ in the range of-100 DEG C to 100 DEG C. The prepared multiphase ceramic material has extremely low porosity, the compactness and strength of the multiphase ceramic material are remarkably improved, and the limitation of the traditional technology is solved. The composite ceramic prepared by the invention can be widely applied to electronic components and products, and has remarkable advantages.

Description

Technical Field

[0001] The present invention relates to the technical field of ceramics, and particularly relates to a composite ceramic and its preparation method and application. Background Art

[0002] The popular method for ceramic products is the powder molding and sintering method, which generally includes three stages: ceramic powder preparation, ceramic molding, and ceramic sintering. Before ceramic sintering, it is a composite composed of many independent solid particles formed by pressing ceramic powder, and there are a large number of pores between the particles. Therefore, it is very difficult to remove the pores during the ceramic powder molding and sintering processes, which is closely related to the inherent properties of the material, the molding process of the material, etc. Especially for current composite ceramic (glass-ceramic) products, due to the process of combining crystal phase and glass phase in the production process, the process of this composite ceramic is very complex, the technical requirements are quite high, and the problem of material compatibility during the preparation process is more difficult to overcome than that of single ceramic products. The prepared composite ceramic has a high porosity and poor density. Especially in the field of electronic devices, the porosity, pore size, and content of composite ceramic products have a very crucial impact on the performance and appearance of the products, including affecting the thermal performance, mechanical performance, surface microstructure, gloss, and transparency of the products, resulting in a series of problems such as poor product quality, low yield, and limited application fields. Summary of the Invention

[0003] Based on this, it is necessary to provide a composite ceramic and its preparation method and application that can obtain a low porosity, high density and strength, and high yield.

[0004] In a first aspect, the present invention provides a preparation method of a composite ceramic, comprising the following steps:

[0005] Crystallize the nepheline-based glass to prepare nepheline glass-ceramics;

[0006] Mix the base material and the nepheline glass-ceramics to prepare a mixed slurry;

[0007] Sinter the mixed slurry to prepare a composite ceramic; the temperature difference between the crystallization temperature and the sintering temperature is in the range of -100°C to 100°C.

[0008] In some embodiments, the crystallization temperature is 700°C - 1400°C; and / or,

[0009] In terms of mass percentage, the crystal phase content of the nepheline glass-ceramics is 10% - 90%.

[0010] In some embodiments, the mixing mass ratio of the base material and the nepheline glass-ceramics is (55 - 85) : (15 - 45).

[0011] In some embodiments, the base material includes one or more of ceramic materials, glass-ceramic materials, and glass materials;

[0012] Optionally, the ceramic material includes one or more of silicon carbide ceramics, silicon oxide ceramics, aluminum oxide ceramics, and zirconium oxide ceramics;

[0013] Optionally, the glass-ceramic material includes one or more of aluminosilicate glass-ceramics, silicate glass-ceramics, borosilicate glass-ceramics, borate glass-ceramics, and phosphate glass-ceramics;

[0014] Optionally, the glass material includes one or more of aluminosilicate glass, borosilicate glass, and soda-lime glass.

[0015] In some embodiments, the mixed slurry further includes pre-sintering before sintering;

[0016] Optionally, the temperature of pre-sintering is 550°C - 900°C;

[0017] Optionally, the sintering temperature is 700°C - 1500°C.

[0018] In some embodiments, the sintering temperature is higher than the pre-sintering temperature;

[0019] Optionally, the heating rate during the process from pre-sintering to sintering is 2°C / min - 5°C / min.

[0020] In some embodiments, the D50 of the mixed slurry is 100nm - 500nm.

[0021] In some embodiments, the mixed slurry further includes one or more treatments such as granulation, pressing, and debinding; and / or,

[0022] After sintering, it further includes cold working and / or toughening treatment.

[0023] In a second aspect, the present invention also provides a composite ceramic, including the composite ceramic prepared by the above-mentioned preparation method of the composite ceramic.

[0024] In a third aspect, the present invention also provides an application of the composite ceramic in electronic components, where the composite ceramic includes the composite ceramic prepared by the above-mentioned preparation method of the composite ceramic, or includes the above-mentioned composite ceramic.

[0025] Compared with the traditional technology, the beneficial effects of the technical solution of the present invention include:

[0026] The present invention prepares nepheline microcrystalline glass by crystallizing nepheline base glass, and then mixes and sinters it with a base material to prepare a composite ceramic. The glass phase contained in the crystallized nepheline microcrystalline glass not only effectively inhibits crack propagation, but also reduces the sintering temperature, reduces the pore content, and improves the densification and strength of the composite ceramic material. At the same time, controlling the temperature difference between the crystallization temperature of the nepheline base glass and the sintering temperature within the range of -100°C to 100°C can control the crystal phase content in the nepheline microcrystalline glass and the crystal phase content formed after sintering with the base material within a reasonable range, ensuring the continuity of the two crystal phases, reducing the defects of non-fusion at the grain boundaries, and being more conducive to improving the densification effect of the composite ceramic. It solves the defects of high pore content, poor densification, and insufficient strength in the preparation of composite ceramics by traditional technologies. When applied in the field of electronic devices, it also improves the product yield, performance, and appearance of the products. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic process flow diagram of the preparation method of the composite ceramic of the present invention.

[0028] Figure 2 It is an SEM image of the composite ceramic prepared in Example 1.

[0029] Figure 3 It is an SEM image of the composite ceramic prepared in Example 5.

[0030] Figure 4 It is an SEM image of the composite ceramic prepared in Comparative Example 1. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0031] For the convenience of understanding the present invention, the following gives preferred embodiments of the present invention to more comprehensively describe the technical solutions of the present invention. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure content of the present invention more thorough and comprehensive.

[0032] It should be noted that the experimental methods without specific conditions in the following embodiments of the present invention are usually carried out under conventional conditions or according to the conditions recommended by the manufacturers. All kinds of common chemical reagents used in the embodiments are commercially available products.

[0033] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which the present invention belongs. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0034] The relevant terms involved in the present invention are explained to facilitate a better understanding of the technical solution of the present invention.

[0035] The composite ceramic has superior properties such as high mechanical strength, adjustable thermal expansion performance, heat shock resistance, chemical corrosion resistance, and low dielectric loss. It is widely used in fields such as mechanical manufacturing, optics, electronics and microelectronics, aerospace, chemistry, industry, biomedicine, and architecture. At present, the manufacturing process of composite ceramics is complex and has high technical requirements. There are problems such as poor quality and low yield in the production process of composite ceramic glass ceramics.

[0036] A relatively popular method for ceramic products is the powder molding and sintering method. Before ceramic sintering, it is a composite composed of many independent solid particles formed by pressing ceramic powder. There are a large number of pores between the particles. At this time, the pore content can reach between 35% and 60%. To completely eliminate all pores, it is related to the inherent properties of the powder or the use of specific forming, sintering and other processes. Ceramic sintering is a thermodynamic process in which microscopic discrete particles form a continuous solid structure through the diffusion of the material phase under high-temperature conditions. The main purpose of ceramic sintering is to densify the green body. During the sintering process of ceramics, there are changes in the microstructure: grain growth and grain boundary formation, powder particles aggregate into grain aggregates, the density of the material increases, and at the same time, there is also the combination of powder particles and the connection, shrinkage and elimination of pores. However, during the high-temperature sintering process of the pressed ceramic powder green body, the particles of the pressed green body undergo mass migration. After reaching a certain sintering temperature, the green body shrinks, grain growth occurs, and some pores are eliminated. At this time, the porosity decreases to 1-20%. Continuing to optimize the sintering process, such as increasing the sintering temperature, will cause overfiring, and the porosity will increase instead. This process is irreversible, resulting in low yield and poor performance. Therefore, there is an urgent need to provide a technical method to solve the problem of pores in ceramic sintering to obtain high-density and high-strength ceramic products and improve the performance of electronic products. Especially in the field of electronic devices, the porosity, pore size and content of composite ceramic products have a very crucial impact on the performance and appearance of the products. For example, in the back cover appearance parts of electronic products, the porosity, pore size and content of composite ceramics will affect the thermal performance, mechanical performance, surface microstructure, gloss and transparency of the products.

[0037] In a first aspect, the present invention provides a method for preparing a composite ceramic, comprising the following steps:

[0038] S10. Crystallize the nepheline-based glass to prepare nepheline glass-ceramics;

[0039] S20. Mix the base material and the nepheline glass-ceramics to prepare a mixed slurry;

[0040] S30. Sinter the mixed slurry to prepare a composite ceramic; the temperature difference between the crystallization temperature and the sintering temperature is in the range of -100°C to 100°C.

[0041] In the preparation process of the composite ceramic, a high-temperature sintering process is required. During this process, crystal growth occurs, resulting in crystal changes, mainly including phase transformation and crystal size change. Among them, volume expansion occurs during phase transformation, and it is difficult to completely wrap the large grains and the glass phase during crystal size change, making it difficult to remove a large number of pores at the grain boundaries and difficult to achieve high density. On the other hand, a phase change reaction occurs during the high-temperature sintering process, and gas is generated during the phase change process. The lithium aluminosilicate-based glass remains in the glass phase without crystallization. Using this non-crystallized glass phase of lithium aluminosilicate-based glass to prepare the composite ceramic will significantly increase the generation of pores during the high-temperature sintering process. In addition, directly using the non-crystallized lithium aluminosilicate-based glass to prepare the composite ceramic, during the preparation process, the high-temperature sintering behavior may occur before the crystallization behavior, resulting in the lithium aluminosilicate crystal not playing a synergistic effect on the composite ceramic. Therefore, in the preparation process of the composite ceramic of the present invention, the lithium aluminosilicate-based glass is first crystallized to form a crystal phase, which is beneficial to achieving better crystal phase fusion during the preparation process of the composite ceramic, significantly reducing the pore content of the material, and improving the density and strength of the material.

[0042] In the preparation process of the composite ceramic, the crystallization temperature and time of the lithium aluminosilicate glass-ceramic are related to the grain size and crystal content of the formed lithium aluminosilicate glass-ceramic. The higher the crystallization temperature or time, the greater the degree of crystallization, so the subsequent sintering temperature requirement is higher. The present invention finds that when the temperature difference between the crystallization temperature and the sintering temperature of the lithium aluminosilicate glass-ceramic is in the range of -100°C to 100°C, it is more beneficial to prepare a composite ceramic with high density. When the temperature difference exceeds the range of -100°C to 100°C, the crystal phase in the lithium aluminosilicate glass-ceramic cannot be completely fused with the crystal phase formed by sintering the base material, reducing the density of the material. If the temperature difference is too large, even grain boundary separation will occur. Therefore, in some embodiments of the present invention, using the temperature difference between the crystallization temperature and the sintering temperature of the lithium aluminosilicate glass-ceramic in the range of -100°C to 100°C is more beneficial to improving the densification effect of the composite ceramic.

[0043] In some embodiments, by mass percentage, the composition of the lithium aluminosilicate-based glass includes 40% - 75% SiO2, 10 - 30% Al2O3, 10 - 30% Li2O3, 2% - 5% Na2O, 1 - 3% K2O, 0 - 1% MgO, 0.5 - 1.5% ZnO, 1.5 - 3% P2O3, and 2 - 4% ZrO2.

[0044] In some embodiments, the crystallization temperature of the lithium aluminosilicate-based glass is 700°C - 1400°C, including but not limited to 700°C, 800°C, 900°C, 1000°C, 1100°C, 1200°C, 1300°C, 1400°C, or any temperature within the range formed by any two of the foregoing and within that range.

[0045] In the present invention, the crystal phase content in the nepheline syenite glass-ceramics prepared at a crystallization temperature of 700 °C - 1400 °C is more suitable for the composite ceramic forming process. When the crystallization temperature is too low (<700 °C), the corresponding crystal phase of nepheline syenite does not appear and has no effect during the high-temperature sintering process. When the crystallization temperature is too high (>1400 °C), the nepheline syenite crystals will decompose and also have no effect during the sintering process.

[0046] In some embodiments, by mass percentage, the crystal phase content of the nepheline syenite glass-ceramics is 10% - 90%, including but not limited to 10%, 20%, 30%, 40%, 45%, 50%, 60%, 70%, 80%, 90% or any range formed by any two of the foregoing and any crystal phase content within that range.

[0047] In some embodiments, during the preparation of the nepheline syenite glass-ceramics, the heating rate during the crystallization process is 5 °C / min - 10 °C / min, including but not limited to 5 °C / min, 6 °C / min, 7 °C / min, 8 °C / min, 9 °C / min, 10 °C / min or any range formed by any two of the foregoing and the heating rate within that range.

[0048] The nepheline syenite glass-ceramics crystallized at 700 °C - 1400 °C are compounded with the base material. The glass phase contained in the nepheline syenite glass-ceramics can not only effectively inhibit crack propagation, but also reduce the sintering temperature and promote the densification of the composite ceramic material. If completely crystallized nepheline microcrystals (crystal content is 100%) are added, a higher sintering temperature is required, the grain growth is too fast, resulting in an increase in porosity and grain boundary defects, and a high gas pore content, which affects the densification and strength. Therefore, the present invention is beneficial to reducing the gas porosity of the composite ceramic product, improving the densification and strength of the material by adding nepheline syenite glass-ceramics. At the same time, the crystallized nepheline syenite glass-ceramics of the present invention are also adapted to the sintering of different base materials, and high-density and high-strength composite products can be obtained.

[0049] In some embodiments, the mixing mass ratio of the base material to the nepheline syenite glass-ceramics is (55 - 85):(15 - 45), including but not limited to 55:45, 60:40, 65:35, 70:30, 75:25, 80:20, 85:15 or any mass ratio range formed by any two of the foregoing and any mass ratio within that range. By adopting the mixing mass ratio range of the present invention, the ratio of the glass phase to the crystal phase during the forming process can be adjusted, and the sintering gas pore content of the composite ceramic can be reduced specifically, thereby improving the densification of the material.

[0050] In some embodiments, the base material includes one or more of ceramic materials, glass-ceramic materials, and glass materials.

[0051] In some embodiments, the ceramic material includes one or more of silicon carbide ceramics, silicon oxide ceramics, aluminum oxide ceramics, and zirconia ceramics.

[0052] In some embodiments, the materials of the glass-ceramics include one or more of aluminosilicate glass-ceramics, silicate glass-ceramics, borosilicate glass-ceramics, borate glass-ceramics, and phosphate glass-ceramics.

[0053] In some embodiments, the glass material includes one or more of aluminosilicate glass, borosilicate glass, and soda-lime glass.

[0054] In some embodiments, the ceramic material and / or the glass material can be waste materials or defective products generated during the production and processing process, which can be reused, without causing waste of resources and saving costs.

[0055] During the preparation process of the composite ceramics, due to the different properties of the base material itself and the lithium nepheline glass-ceramics, the sintering temperatures of the base material itself and the lithium nepheline glass-ceramics are different, and the sintering temperature after their compounding is also different. Therefore, as a non-limiting example, in some embodiments, pre-sintering is also included before sintering the mixed slurry; further, the treatment method of pre-sintering + sintering can better achieve the fusion between crystal phases, reduce the porosity, and improve the density and strength of the composite ceramic material. Pre-sintering can remove some residual organic matters, avoid the rapid decomposition of organic matters at too high a temperature to generate gases, resulting in material expansion, increased pores, and even cracking. At the same time, pre-sintering can also initially form crystal nuclei, making it have certain strength and stability, providing relatively stable conditions for the growth and development of grains, being able to maintain its shape, and preparing for withstanding higher temperatures and pressures during the subsequent sintering process, which is beneficial to the formation of crystal nuclei. The subsequent sintering can further promote grain growth and densification, further reduce and eliminate the pores inside the material, make the grain boundaries tend to be stable, and improve the density and strength of the composite ceramics. At the same time, during the sintering process, phase changes of different degrees also occur, which can form a better composite structure, thus better achieving the technical effects of the present invention.

[0056] In some embodiments, the temperature of pre-sintering is 550°C - 900°C, including but not limited to 550°C, 600°C, 650°C, 700°C, 750°C, 800°C, 850°C, 900°C, or the temperature ranges formed by any two of the foregoing and any temperature within the ranges.

[0057] In some embodiments, the time of pre-sintering is 1h - 5h.

[0058] In some embodiments, the sintering temperature is 700°C - 1500°C, including but not limited to 700°C, 750°C, 800°C, 850°C, 900°C, 950°C, 1000°C, 1100°C, 1200°C, 1300°C, 1400°C, 1500°C, or the temperature ranges formed by any two of the foregoing and any temperature within the ranges.

[0059] In some embodiments, the time of pre-sintering is 2h - 10h.

[0060] In some embodiments, the sintering temperature is higher than the pre-sintering temperature, and the heating rate during the process from pre-sintering to sintering is 2°C / min - 5°C / min, including but not limited to 2°C / min, 2.5°C / min, 3°C / min, 3.5°C / min, 4°C / min, 4.5°C / min, 5°C / min, or the ranges formed by any two of the foregoing and the heating rates within the ranges.

[0061] In some embodiments, the D50 particle size of the base material is 0.1μm - 1mm, and preferably 0.1μm - 1μm is adopted.

[0062] In some embodiments, the D50 particle size of the nepheline microcrystalline glass is 0.1μm - 1mm, and preferably 0.1μm - 0.5μm is adopted.

[0063] In some embodiments, the nepheline microcrystalline glass can be ball-milled into particles with a D50 particle size of 0.1μm - 1mm. The planetary ball mill is selected for ball milling, and balls with a diameter of 2mm - 10mm are selected. The materials of the balls and the jars can be selected from zirconia, agate, quartz, corundum, etc.

[0064] In some embodiments, during the mixing process of the base material and the nepheline microcrystalline glass, sanding treatment is adopted, and zirconia with a diameter of 0.1mm - 0.5mm is selected for sanding.

[0065] In some embodiments, the D50 of the mixed slurry is 100nm - 500nm, including but not limited to 100nm, 200nm, 300nm, 400nm, 500nm, or the ranges formed by any two of the foregoing and the particle sizes within the ranges.

[0066] In some embodiments, the mixed slurry further includes one or more treatments such as granulation, pressing, and debinding.

[0067] In some embodiments, spray granulation is adopted for granulation.

[0068] In some embodiments, the temperature of spray granulation is 230°C - 280°C, including but not limited to 230°C, 240°C, 250°C, 260°C, 270°C, 280°C, or the range formed by any two of the foregoing and the temperatures within the range.

[0069] In some embodiments, the atomization rotation speed of spray granulation is 140 r / min - 200 r / min, including but not limited to 140 r / min, 150 r / min, 160 r / min, 170 r / min, 180 r / min, 190 r / min, 200 r / min, or the range formed by any two of the foregoing and the atomization rotation speed within the range.

[0070] In some embodiments, the humidity of the granulated powder obtained by spray granulation is 0.3% - 0.5%, including but not limited to 0.3%, 0.35%, 0.4%, 0.45%, 0.5%, or the range formed by any two of the foregoing and the humidity within the range.

[0071] In some embodiments, spherical particles of 80 μm - 100 μm are obtained by spray granulation, including but not limited to 80 μm, 85 μm, 90 μm, 95 μm, 100 μm, or the range formed by any two of the foregoing and the particle size within the range.

[0072] In some embodiments, screening can be performed after granulation, and the screening mesh number is 200 meshes.

[0073] In some embodiments, the pressure of pressing is 300 KN - 400 KN, including but not limited to 300 KN, 310 KN, 320 KN, 330 KN, 340 KN, 350 KN, 360 KN, 370 KN, 380 KN, 390 KN, 400 KN, or the range formed by any two of the foregoing and the pressure within the range.

[0074] In some embodiments, the pressing die includes but not limited to being circular, and preferably the diameter of the circular die is 45 mm - 48 mm.

[0075] In some embodiments, the temperature of debinding is 350°C - 550°C, including but not limited to 350°C, 380°C, 400°C, 420°C, 450°C, 480°C, 500°C, 520°C, 550°C, or the range formed by any two of the foregoing and the temperature within the range.

[0076] In some embodiments, the time of debinding is 12 h - 36 h.

[0077] In some embodiments, cooling is also performed after sintering, and the cooling process is: cooling at a cooling rate of 0.5°C / min - 2°C / min to 500°C, and then naturally cooling to room temperature.

[0078] In some embodiments, cooling is also performed after sintering, and the cooling process is as follows: controlling the cooling rate to be 0.5 °C / min - 2 °C / min and cooling to room temperature.

[0079] In some embodiments, cooling is also performed after sintering, and the cooling process is as follows: naturally cooling to room temperature.

[0080] In some embodiments, after sintering, cold working and / or toughening treatment are also included.

[0081] In some embodiments, the cold working includes, but is not limited to, one or more of the processes of precision engraving, grinding, and polishing.

[0082] In some embodiments, the shape of the precision engraving includes, but is not limited to, a circle, preferably a circle with a diameter of 45 mm - 48 mm and a thickness of 0.8 mm.

[0083] In some embodiments, the toughening reagents used in the toughening treatment process include, but are not limited to, sodium salts and / or potassium salts. As non-limiting examples, the sodium salts include one or more of sodium nitrate, sodium carbonate, sodium sulfate, and sodium chloride; the potassium salts include one or more of potassium nitrate, potassium carbonate, potassium sulfate, and potassium chloride.

[0084] In some embodiments, the temperature of the toughening treatment is 420 °C - 500 °C, including, but not limited to, 420 °C, 450 °C, 480 °C, 500 °C, or the range formed by any two of the foregoing and the temperatures within that range.

[0085] In some embodiments, the time of the toughening treatment is 2 h - 12 h, including, but not limited to, 2 h, 4 h, 6 h, 8 h, 10 h, 12 h, or the range formed by any two of the foregoing and the time within that range.

[0086] In some embodiments, the toughening treatment includes at least two stages of toughening treatment, so that the technical effects of the present invention can be better achieved.

[0087] In some embodiments, the toughening includes: a first-stage toughening, with the toughening reagent being a sodium salt, the toughening temperature being 420 °C - 500 °C, and the toughening time being 2 h - 12 h; a second-stage toughening, with the toughening reagent being a potassium salt, the toughening temperature being 420 °C - 500 °C, and the toughening time being 2 h - 12 h.

[0088] In some embodiments, a cleaning process is also included after the toughening.

[0089] In a second aspect, the present invention also provides a composite ceramic, including the composite ceramic prepared by the preparation method of the composite ceramic provided in the first aspect. The composite ceramic prepared by the present invention has excellent properties, especially low porosity, good denseness, and high strength.

[0090] In a third aspect, the present invention also provides an application of a multiphase ceramic in an electronic component, where the multiphase ceramic includes the multiphase ceramic obtained by the method for preparing a multiphase ceramic provided in the first aspect, or includes the multiphase ceramic provided in the second aspect.

[0091] For the experimental parameters not specified in the following specific examples, priority is given to referring to the guidance provided in this application document. It is also possible to refer to experimental manuals in the art or other experimental methods known in the art, or refer to the experimental conditions recommended by the manufacturer.

[0092] The raw materials and reagents involved in the following specific examples can be obtained commercially, or can be prepared by those skilled in the art according to known means.

[0093] The models and sources of some raw materials involved in the embodiments of the present invention are as follows:

[0094] Silicon carbide: particle size is 1 μm.

[0095] By mass percentage, the composition of the leucite-based glass is: SiO2 58%, Al2O3 17%, Li2O 15%, Na2O 3%, K2O 1%, MgO 1%, ZnO 1%, P2O3 2%, and ZrO2 2%.

[0096] Part I. Preparation of Raw Materials

[0097] Preparation of basic materials:

[0098] Ceramic T1: Silicon carbide is sintered at 1400 °C to obtain silicon carbide ceramic.

[0099] Ceramic T2: Silicon oxide is sintered at 1200 °C to obtain silicon oxide ceramic.

[0100] Glass-ceramic W1: Lithium aluminosilicate glass-ceramic (grade SJW1, purchased from Chengdu Guangming), pre-crystallized at 750 °C and held for 6 h, and then sintered at 800 °C to obtain glass-ceramic.

[0101] Glass G1: Aluminosilicate glass (Corning Gorilla Glass 3), sintered at 700 °C to obtain glass.

[0102] Preparation of leucite glass-ceramic:

[0103] Leucite glass-ceramic A1: The leucite-based glass is heat-treated at 1600 °C for 12 h to melt into glass, and then crystallized at 1300 °C for 6 h to obtain leucite glass-ceramic with a crystal phase content of 80%.

[0104] Lithium nepheline glass-ceramic A2: The lithium nepheline base glass is heat-treated at 1600 °C for 12 h to be melted into glass, and then crystallized at 1200 °C for 6 h to obtain a lithium nepheline glass-ceramic with a crystal phase content of 70%.

[0105] Lithium nepheline glass-ceramic A3: The lithium nepheline base glass is heat-treated at 1600 °C for 12 h to be melted into glass, and then crystallized at 750 °C for 6 h to obtain a lithium nepheline glass-ceramic with a crystal phase content of 15%.

[0106] Lithium nepheline glass-ceramic A4: The lithium nepheline base glass is heat-treated at 1600 °C for 12 h to be melted into glass, and then crystallized at 700 °C for 6 h to obtain a lithium nepheline glass-ceramic with a crystal phase content of 10%.

[0107] Lithium nepheline glass-ceramic A5: A lithium nepheline glass-ceramic with a crystal phase content of 100% is obtained through a purification method.

[0108] Lithium nepheline glass-ceramic A6: The lithium nepheline base glass is heat-treated at 1600 °C for 12 h to be melted into glass, and then crystallized at 650 °C for 6 h and held for 6 h to obtain a lithium nepheline glass-ceramic with a crystal phase content of 0%.

[0109] Lithium nepheline glass-ceramic A7: The lithium nepheline base glass is heat-treated at 1600 °C for 12 h to be melted into glass, and then crystallized at 1450 °C for 6 h and held for 6 h to obtain a lithium nepheline glass-ceramic with a crystal phase content of 0%.

[0110] Second part: Preparation of composite ceramics

[0111] Example 1

[0112] The lithium nepheline glass-ceramic A1 is roll-pressed into 0.5 mm granular particles and ball-milled into a 2 μm glass powder slurry.

[0113] The ceramic T1 and the glass powder slurry are mixed at a mass ratio of 45:55 and sand-milled into a 300 nm nano-composite slurry.

[0114] The nano-composite slurry is spray granulated at a granulation temperature of 250 °C, an atomization rotation speed of 160 r / min, and the granulated powder is maintained at a humidity of 0.4%. After granulation, it is in the shape of 100 μm spheres. The dried powder is screened through a 200-mesh sample sieve; then a circular mold with a diameter of 65 mm is selected to press the screened dried powder at a pressure of 350 KN to obtain a pressed blank (round slice).

[0115] Debind the compacted green body at 500 °C for 24 h, then carry out pre-sintering. The pre-sintering temperature is 900 °C, hold for 2 h, heat up to 1350 °C at a heating rate of 5 °C / min for sintering. The sintering temperature is 1350 °C, hold for 5 h. After sintering is completed, cool down to 500 °C at a cooling rate of 1 °C / min, and then cool naturally to room temperature.

[0116] Precision machine the above sintered wafer into a wafer with a diameter of 48 mm and a thickness of 0.8 mm, then grind and finish polish it into a bright surface, control the thickness to 0.7 mm, and then carry out two-stage toughening. Immerse the above wafer in a mixed sodium salt, including 80% sodium nitrate and 20% sodium carbonate, melt it into a liquid at 500 °C, carry out the first-stage toughening for 6 h, then place the wafer in a mixed potassium salt, including 80% potassium nitrate and 20% sodium carbonate, melt it into a liquid state at 500 °C, carry out the second-stage toughening for 6 h, and obtain a composite ceramic after cleaning.

[0117] Example 2

[0118] Roll the nepheline microcrystalline glass A1 into 0.5 mm granular form, and ball mill it into a 2 μm glass powder slurry;

[0119] Mix the ceramic T1 and the glass powder slurry in a mass ratio of 70:30, and sand mill it into a 300 nm nano-composite slurry.

[0120] Carry out spray granulation on the nano-composite slurry. The granulation temperature is 250 °C, the atomization rotation speed is 160 r / min, the humidity of the granulated powder is maintained at 0.4%, and the granulated product is in the shape of 100 μm spheres after granulation. Screen the dried powder through a 200-mesh sample sieve; then select a circular mold with a diameter of 65 mm to press the screened dried powder, and the pressure is 350 KN to obtain a compacted green body (wafer).

[0121] Debind the compacted green body at 500 °C for 24 h, then carry out pre-sintering. The pre-sintering temperature is 900 °C, hold for 2 h, heat up to 1380 °C at a heating rate of 5 °C / min for sintering. The sintering temperature is 1380 °C, hold for 5 h. After sintering is completed, cool down to 500 °C at a cooling rate of 1 °C / min, and then cool naturally to room temperature.

[0122] Precision machine the above sintered wafer into a wafer with a diameter of 48 mm and a thickness of 0.8 mm, then grind and finish polish it into a bright surface, control the thickness to 0.7 mm, and then carry out two-stage toughening. Immerse the above wafer in a mixed sodium salt, including 80% sodium nitrate and 20% sodium carbonate, melt it into a liquid at 500 °C, carry out the first-stage toughening for 6 h, then place the wafer in a mixed potassium salt, including 80% potassium nitrate and 20% sodium carbonate, melt it into a liquid state at 500 °C, carry out the second-stage toughening for 6 h, and obtain a composite ceramic after cleaning.

[0123] Example 3

[0124] The nepheline microcrystalline glass A1 was roll-pressed into 0.5-mm particles and ball-milled into a 2-μm glass powder slurry.

[0125] The ceramic T1 and the glass powder slurry were mixed at a mass ratio of 85:15 and sand-milled into a 300-nm nano-mixed slurry.

[0126] The nano-mixed slurry was spray granulated at a granulation temperature of 250°C, an atomization rotation speed of 160 r / min, and a granulated powder humidity of 0.4%. After granulation, it was in the shape of 100-μm spheres. The dried powder was screened through a 200-mesh sampling sieve. Then, a circular mold with a diameter of 65 mm was selected to press the screened dried powder at a pressure of 350 KN to obtain a pressed blank (wafer).

[0127] The pressed blank was debinded at 500°C for 24 h, and then pre-sintered at a pre-sintering temperature of 900°C for 2 h. It was heated to 1400°C at a heating rate of 5°C / min for sintering. The sintering temperature was 1400°C, and it was held for 5 h. After sintering, it was cooled to 500°C at a cooling rate of 1°C / min and then naturally cooled to room temperature.

[0128] The sintered wafer was precision machined into a wafer with a diameter of 48 mm and a thickness of 0.8 mm, then ground and precision polished into a bright surface with a thickness controlled to 0.7 mm. Then, it was subjected to two-stage toughening. The wafer was immersed in a mixed sodium salt, including 80% sodium nitrate and 20% sodium carbonate, melted into a liquid at 500°C, and subjected to the first-stage toughening for 6 h. Then, the wafer was placed in a mixed potassium salt, including 80% potassium nitrate and 20% sodium carbonate, melted into a liquid at 500°C, and subjected to the second-stage toughening for 6 h. After cleaning, a composite ceramic was obtained.

[0129] Example 4

[0130] The nepheline microcrystalline glass A2 was roll-pressed into 0.5-mm particles and ball-milled into a 2-μm glass powder slurry.

[0131] The ceramic T2 and the glass powder slurry were mixed at a mass ratio of 70:30 and sand-milled into a 300-nm nano-mixed slurry.

[0132] The nano-mixed slurry was spray granulated at a granulation temperature of 250°C, an atomization rotation speed of 160 r / min, and a granulated powder humidity of 0.4%. After granulation, it was in the shape of 100-μm spheres. The dried powder was screened through a 200-mesh sampling sieve. Then, a circular mold with a diameter of 65 mm was selected to press the screened dried powder at a pressure of 350 KN to obtain a pressed blank (wafer).

[0133] Debind the compacted green body at 500°C for 24 h, then carry out pre-sintering. The pre-sintering temperature is 900°C, hold for 2 h, and then heat up to 1250°C at a heating rate of 5°C / min for sintering. The sintering temperature is 1250°C, hold for 5 h. After sintering is completed, cool down to 500°C at a cooling rate of 1°C / min, and then naturally cool to room temperature.

[0134] Precision machine the sintered wafer into a wafer with a diameter of 48 mm and a thickness of 0.8 mm, then grind and finish polish it to a bright surface, control the thickness to 0.7 mm, and then carry out two-stage toughening. Immerse the above wafer in a mixed sodium salt, including 80% sodium nitrate and 20% sodium carbonate, melt it into a liquid at 500°C, and carry out the first-stage toughening for 6 h. Then place the wafer in a mixed potassium salt, including 80% potassium nitrate and 20% sodium carbonate, melt it into a liquid state at 500°C, and carry out the second-stage toughening for 6 h. After cleaning, a composite ceramic is obtained.

[0135] Example 5

[0136] Roll the nepheline microcrystalline glass A3 into 0.5 mm granular form, and ball mill it into a 2 μm glass powder slurry;

[0137] Mix the microcrystalline glass W1 and the glass powder slurry in a mass ratio of 70:30, and sand mill it into a 300 nm nano-composite slurry.

[0138] Carry out spray granulation on the nano-composite slurry. The granulation temperature is 250°C, the atomization rotation speed is 160 r / min, the humidity of the granulated powder is maintained at 0.4%, and the granulated product is in the shape of 100 μm spheres after granulation. Screen the dried powder through a 200-mesh sample sieve; then select a circular mold with a diameter of 65 mm to press the screened dried powder, and the pressure is 350 KN to obtain a compacted green body (wafer).

[0139] Debind the compacted green body at 500°C for 24 h, then carry out pre-sintering. The pre-sintering temperature is 600°C, hold for 2 h, and then heat up to 850°C at a heating rate of 5°C / min for sintering. The sintering temperature is 850°C, hold for 5 h. After sintering is completed, cool down to 500°C at a cooling rate of 1°C / min, and then naturally cool to room temperature.

[0140] Precision machine the sintered wafer into a wafer with a diameter of 48 mm and a thickness of 0.8 mm, then grind and finish polish it to a bright surface, control the thickness to 0.7 mm, and then carry out two-stage toughening. For the first-stage toughening, use pure sodium nitrate for toughening at 460°C for 6 h, and then carry out toughening using pure potassium nitrate at 460°C for 6 h. After cleaning, a composite ceramic is obtained.

[0141] Example 6

[0142] The spodumene glass-ceramic A4 was roll-pressed into 0.5 mm granular form and ball-milled into a 2 μm glass powder slurry.

[0143] Glass G1 and the glass powder slurry were mixed at a mass ratio of 70:30 and sand-milled into a 300 nm nano-mixed slurry.

[0144] The nano-mixed slurry was spray granulated at a granulation temperature of 250 °C, an atomization rotation speed of 160 r / min, and the granulated powder had a humidity of 0.4%. After granulation, it was in the form of 100 μm spheres. The dried powder was screened through a 200-mesh sieve; then a circular mold with a diameter of 65 mm was used to press the screened dried powder at a pressure of 350 KN to obtain a pressed blank (round wafer).

[0145] The pressed blank was debinded at 500 °C for 24 h, and then pre-sintered. The pre-sintering temperature was 550 °C, held for 2 h, heated to 750 °C at a heating rate of 5 °C / min for sintering. The sintering temperature was 750 °C, held for 5 h. After sintering, it was cooled to 500 °C at a cooling rate of 1 °C / min and then naturally cooled to room temperature.

[0146] The above sintered round wafer was precision carved into a round wafer with a diameter of 48 mm and a thickness of 0.8 mm, then ground and precision polished to a bright surface, with the thickness controlled to 0.7 mm, and then two-stage tempering was carried out. For the first-stage tempering, pure sodium nitrate was used for tempering at 420 °C for 6 h, and then for tempering, pure potassium nitrate was used for tempering at 420 °C for 6 h. After cleaning, a composite ceramic was obtained.

[0147] Example 7

[0148] The difference from Example 2 is that in this example, ceramic T1 and the glass powder slurry (prepared from spodumene glass-ceramic A1) were mixed at a mass ratio of 90:10, and the other raw materials, their ratios, and the preparation steps were the same as those in Example 2.

[0149] Example 8

[0150] The difference from Example 2 is that in this example, ceramic T1 and the glass powder slurry (prepared from spodumene glass-ceramic A1) were mixed at a mass ratio of 30:70, and the other raw materials, their ratios, and the preparation steps were the same as those in Example 2.

[0151] Comparative Example 1

[0152] The difference from Example 2 is that in this comparative example, the added glass powder slurry was replaced with spodumene base glass, and it was melted into glass (without crystallization treatment) by heat treatment at 1600 °C for 12 h, and the other raw materials, their ratios, and the preparation steps were the same as those in Example 2.

[0153] Comparative Example 2

[0154] The difference from Example 2 is that in this example, nepheline microcrystalline glass A5 is used to replace nepheline microcrystalline glass A1 in Example 2, and the remaining raw materials, their proportions, and the preparation steps are the same as those in Example 2.

[0155] Comparative Example 3

[0156] The difference from Example 2 is that in this comparative example, nepheline microcrystalline glass A6 is used to replace nepheline microcrystalline glass A1 in Example 2, the pre-sintering temperature is 700 °C, and the sintering temperature is 750 °C. The remaining raw materials, their proportions, and the preparation steps are the same as those in Example 2.

[0157] Comparative Example 4

[0158] The difference from Example 2 is that in this comparative example, nepheline microcrystalline glass A7 is used to replace nepheline microcrystalline glass A1 in Example 2, and the remaining raw materials, their proportions, and the preparation steps are the same as those in Example 2.

[0159] Comparative Example 5

[0160] The difference from Example 2 is that in this comparative example, the sintering temperature is 1450 °C, and the remaining raw materials, their proportions, and the preparation steps are the same as those in Example 2.

[0161] Comparative Example 6

[0162] The difference from Example 2 is that in this comparative example, the sintering temperature is 1150 °C, and the remaining raw materials, their proportions, and the preparation steps are the same as those in Example 2.

[0163] Test Example 1. Performance Test of Composite Glass

[0164] Perform performance tests on the composite glasses prepared in Examples 1 to 8 and Comparative Examples 1 to 5, including the surface state, cross-section state, relative density ratio, and the test of resisting free fall from 5 m. The test methods are as follows:

[0165] (1) Surface state: Use reflective inspection, with the light source illuminance of 1500 - 2000 Lux, and check whether pores with D > 2 µm appear on the surface of the test sample. Pores with < 2 µm are invisible to the naked eye under reflective conditions, and this is used as the standard for judging the presence or absence of pores.

[0166] (2) Cross-section state: Observe the cross-section morphology under an SEM microscope.

[0167] (3) Relative density ratio %: Calculate through the following formula (I). The higher the relative density ratio, the better the compactness;

[0168] (I)

[0169] In the formula: ρ0 is the product density of the composite ceramic.

[0170] ρ1 is the density of the base material after heat treatment (i.e., the density of T1, T2, W1, or G1).

[0171] ρ2 is the density of the nepheline syenite base glass after heat treatment (i.e., the density of A1 - A8),

[0172] m1 is the proportion of the addition amount of the base material, %.

[0173] m1 is the proportion of the addition amount of the nepheline syenite base glass, %.

[0174] (3) Resistance to free fall from 5M: Clamp the product to a height of 1M - 5M, instantaneously release it at a gradient of 0.5M, and drop it horizontally. The ground for dropping is a marble slab. Record the final height of dropping to the ground and determine whether the sample integrity is OK / NG.

[0175] The results measured according to the above test method are shown in Table 1;

[0176] Table 1: Performance test results of the composite ceramics

[0177]

[0178] The preparation method of the composite ceramics of the present invention can significantly reduce the air holes at the grain boundaries and obtain a dense composite ceramic material. As can be seen from the results in Table 1, the composite ceramics prepared in Examples 1 - 6 have no air holes on the surface, high density, and excellent resistance to free fall performance; the composite ceramics prepared in Examples 7 - 8 have a small amount of air holes on the surface, and the density can also reach 85% - 90%. For Comparative Example 1, the non - crystallized nepheline syenite base glass is used, and the crystal phase fusion cannot be achieved, with a high air hole content, and both the density and strength are poor. In Comparative Example 2, the crystal boundaries cannot be fused, resulting in a high air hole content. The crystal phase content of the nepheline syenite glass - ceramics prepared in Comparative Examples 3 - 4 is 0%, and the effects of the examples cannot be achieved. During the preparation process of Comparative Examples 5 - 6, the difference between the crystallization temperature and the sintering temperature exceeds the range of - 100°C to 100°C, the density is poor, and the air hole content is relatively large.

[0179] The technical features of the above - described embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above - described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope recorded in this specification.

[0180] The above - described embodiments only represent several implementation manners of the present invention. Their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several deformations and improvements can be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the present invention patent shall be subject to the appended claims.

Claims

1. A preparation method of a composite ceramic, characterized in that, It includes the following steps: Crystallize the nepheline syenite base glass to prepare nepheline syenite glass-ceramics; Mix the base material and the nepheline syenite glass-ceramics to prepare a mixed slurry; Sinter the mixed slurry to prepare a composite ceramic; the temperature difference between the crystallization temperature and the sintering temperature is in the range of -100°C to 100°C.

2. The preparation method of the multiphase ceramic according to claim 1, characterized in that, The crystallization temperature is 700°C - 1400°C; and / or, By mass percentage, the crystalline phase content of the nepheline syenite glass-ceramics is 10% - 90%.

3. The preparation method of the multiphase ceramic according to claim 1, characterized in that, The mixing mass ratio of the base material and the nepheline syenite glass-ceramics is (55 - 85):(15 - 45).

4. The preparation method of the multiphase ceramic according to claim 1, characterized in that, The base material includes one or more of ceramic materials, glass-ceramic materials, and glass materials; Optionally, the ceramic material includes one or more of silicon carbide ceramics, silicon oxide ceramics, alumina ceramics, and zirconia ceramics; Optionally, the glass-ceramic material includes one or more of aluminosilicate glass-ceramics, silicate glass-ceramics, borosilicate glass-ceramics, borate glass-ceramics, and phosphate glass-ceramics; Optionally, the glass material includes one or more of aluminosilicate glass, borosilicate glass, and soda-lime glass.

5. The preparation method of the multiphase ceramic according to claim 1, characterized in that, Before sintering the mixed slurry, it also includes pre-sintering; Optionally, the pre-sintering temperature is 550°C - 900°C; Optionally, the sintering temperature is 700°C - 1500°C.

6. The preparation method of the composite ceramic according to claim 5, characterized in that, The sintering temperature is higher than the pre-sintering temperature; Optionally, the heating rate during the process from pre-sintering to sintering is 2°C / min - 5°C / min.

7. The preparation method of the multiphase ceramic according to claim 1, characterized in that, The D50 particle size of the mixed slurry is 100nm - 500nm.

8. The preparation method of the multiphase ceramic according to any one of claims 1 to 7, characterized in that, The mixed slurry also includes one or more treatments such as granulation, pressing, and debinding; and / or, After sintering, it also includes cold working and / or toughening treatment.

9. A composite ceramic, characterized in that, It includes a composite ceramic prepared by the method for preparing a composite ceramic according to any one of claims 1 to 8.

10. Application of the multiphase ceramic in electronic components, characterized in that, The composite ceramic includes a composite ceramic prepared by the method for preparing a composite ceramic according to any one of claims 1 to 8, or includes the composite ceramic according to claim 9.

Images