A zirconia ceramic material and a method for producing the same

Abstract

The application relates to the technical field of ceramic materials, in particular to a zirconia ceramic material and a preparation method thereof. The preparation method of the zirconia ceramic material comprises the following steps: step one, mixing and stirring zirconia, modified boron-doped molybdenum carbide, carbon nanotubes, cerium oxide, a dispersing agent and an ethanol aqueous solution to obtain a mixed solution; ball milling the mixed solution to obtain a ball-milled mixed solution; step two, adopting a slip casting method to obtain a wet body from the ball-milled mixed solution, and then using a hydraulic machine to press and form the wet body into a green body; step three, cutting the green body to obtain a zirconia ceramic body; and step four, sintering the zirconia ceramic body to obtain the zirconia ceramic material. The preparation method is simple and low in cost, the prepared zirconia ceramic material has good mechanical properties, a compact structure and good wear resistance.

Description

Technical Field

[0001] This invention relates to the field of ceramic materials technology, specifically to a zirconia ceramic material and its preparation method. Background Technology

[0002] Zirconia ceramics, as a high-performance inorganic non-metallic material, have been widely used in aerospace, medical devices, electronics, and chemical industries due to their excellent mechanical properties, chemical stability, and biocompatibility. The main component of zirconia ceramics is zirconia, and its unique phase transformation characteristics and excellent wear and corrosion resistance make it stand out among many materials.

[0003] Traditional methods for preparing zirconia ceramics mainly include solid-state sintering and liquid-phase sintering. Solid-state sintering involves sintering zirconia powder at high temperatures to prepare ceramics; however, ceramics prepared using this method often suffer from uneven grain size and microstructural defects, affecting the overall performance of the material. While liquid-phase sintering can produce zirconia ceramics with fine grains and uniform structure, it requires precise control of temperature and atmosphere during the sintering process, resulting in relatively high production costs.

[0004] With the development of materials science and preparation technology, researchers are constantly exploring new preparation methods to optimize the properties of zirconia ceramics. For example, novel preparation techniques such as sol-gel methods, hydrothermal synthesis, and spark plasma sintering have been applied to the preparation of zirconia ceramics. These methods can rapidly prepare high-performance zirconia ceramics at relatively low temperatures and facilitate precise control of the microstructure, thereby improving the mechanical properties and reliability of the material. Although existing zirconia ceramic preparation technologies have made some progress, some technical challenges remain, such as high sintering temperatures, long cycles, high energy consumption, and difficulty in controlling the microstructure. Furthermore, how to further improve the mechanical properties of zirconia ceramics, reduce costs, and achieve green and environmentally friendly production through improvements in preparation methods remains a focus of attention for materials scientists and engineers.

[0005] Therefore, the present invention aims to provide a novel zirconia ceramic and its preparation method. This method aims to prepare zirconia ceramics with higher strength, better wear resistance and superior microstructure by optimizing the raw material ratio, improving the preparation process and sintering regime, so as to meet the urgent needs of modern industry for high-performance ceramic materials. Summary of the Invention

[0006] To address the shortcomings of the existing technology, this invention provides a zirconia ceramic material and its preparation method.

[0007] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0008] A method for preparing a zirconia ceramic material includes the following steps:

[0009] Step 1: Mixing: Mix 60-100 parts by weight of zirconium oxide, 5-12 parts by weight of modified boron-doped molybdenum carbide, 1-3 parts by weight of carbon nanotubes, 2-5 parts by weight of cerium oxide, 5-10 parts by weight of dispersant, and 80-150 parts by weight of 40-60 wt% ethanol aqueous solution to obtain a mixture; ball mill the mixture to obtain a ball-milled mixture.

[0010] Step 2, Shaping: The ball mill mixture is used to obtain a wet blank by slip casting, and then a hydraulic press is used to press the wet blank into shape to obtain a green blank;

[0011] Step 3: Processing: The green body is machined to obtain a zirconia ceramic green body;

[0012] Step 4: Sintering: The above-mentioned zirconia ceramic blank is sintered to obtain zirconia ceramic material.

[0013] Preferably, the ball milling rate in step one is 160-240 r / min, and the ball milling time is 2-5 h.

[0014] Preferably, the pressing pressure in step two is 180-260 PMa, and the pressing time is 3-7 min.

[0015] Preferably, the sintering temperature in step four is 1500-1800℃, and the sintering time is 3-6h.

[0016] Hydroxypropyl methylcellulose is a nonionic cellulose ether with hydrophilic properties, capable of forming a network structure in aqueous solution, which helps improve the stability of suspensions; polyvinyl alcohol is a water-soluble polymer with good dispersibility and can form a protective layer on the surface of solid particles to prevent particle aggregation.

[0017] When hydroxypropyl methylcellulose and polyvinyl alcohol are used in combination, they can work together using their different dispersion mechanisms to more effectively prevent the aggregation and sedimentation of zirconium oxide and other solid particles, thereby improving the dispersion stability of the entire system. This allows for uniform physical and chemical changes during the subsequent calcination process, resulting in a uniform microstructure and better material properties. It also reduces the risk of porosity and crack defects caused by particle aggregation during calcination, leading to a denser packing of ceramic materials. This helps optimize grain growth, resulting in a finer and more uniform grain structure, and improving the strength, toughness, and density of the ceramic materials.

[0018] Preferably, the dispersant includes at least one of hydroxypropyl methylcellulose, polyacrylic acid, polyvinyl alcohol, polyethylene glycol, and ammonium polyacrylate; further, the dispersant is composed of hydroxypropyl methylcellulose and polyvinyl alcohol in a mass ratio of 1:(1.2-2.5).

[0019] Molybdenum carbide can be used to obtain composite materials with small particle size at relatively low temperatures. Moreover, molybdenum carbide composite materials with different morphologies and structures can be prepared by doping and modification. Modified boron-doped molybdenum carbide is prepared by coating molybdenum carbide with silica and then surface-modifying it with N-(6-aminohexyl)aminomethyltriethoxysilane.

[0020] Boron doping can alter the microstructure of molybdenum carbide, increasing its toughness. Modified boron-doped molybdenum carbide is a hard material; its addition can improve the hardness and wear resistance of zirconia ceramics. It can promote grain refinement and enhance interfacial bonding between different phases in zirconia ceramics, thereby improving the material's uniformity and mechanical properties. It also helps improve the material's wear resistance and structural stability. Furthermore, the addition of modified boron-doped molybdenum carbide helps optimize the sintering process, potentially lowering the sintering temperature and increasing the sintering rate, thus saving energy and reducing production costs.

[0021] The introduction of silane coupling agents improves the dispersion of boron-doped molybdenum carbide in zirconia ceramic matrices, reducing particle aggregation and resulting in a more uniform microstructure, which helps improve the material's density and strength. Modified boron-doped molybdenum carbide acts as a nucleus for grain boundary formation during calcination, promoting grain growth and grain boundary formation; the increased number of grain boundaries enhances the material's strength and toughness. Furthermore, silane coupling agents can chemically react with the surface of zirconia particles in the ceramic during calcination, forming strong chemical bonds. This enhanced interparticle bonding strengthens the overall compactness of the ceramic material. In addition, during calcination, silane coupling agents reduce porosity and defects in the ceramic material. Because silane coupling agents increase interparticle bonding, they facilitate gas expulsion and seal of micropores during sintering, thereby reducing porosity and improving the material's density.

[0022] Preferably, the method for preparing the modified boron-doped molybdenum carbide includes the following steps:

[0023] S1. Molybdenum powder and carbon powder are uniformly mixed, anhydrous ethanol is added, the mixture is ground, pressed into tablets, and melted to obtain the Mo2C matrix.

[0024] S2 grinds the above Mo2C matrix with boric acid, then calcines it in a tube furnace, cools it to room temperature, washes it, filters it, and dries it to obtain boron-doped molybdenum carbide.

[0025] S3 disperses the above boron-doped molybdenum carbide in an aqueous ethanol solution, stirs until homogeneous, adds ammonia and tetraethyl orthosilicate and stirs to react, filters, washes and dries to obtain silica-coated boron-doped molybdenum carbide; adds N-(6-aminohexyl)aminomethyltriethoxysilane and stirs to obtain modified boron-doped molybdenum carbide.

[0026] The specific reaction mechanism is as follows: S1 Preparation of Mo2C matrix: Molybdenum powder and carbon powder are uniformly mixed as raw materials, and anhydrous ethanol is added for grinding. Ethanol acts as a solvent and grinding aid, which helps to form a uniform suspension and prevents the aggregation of powder particles. The mixed powder is pressed into tablets under a pressure of 120-180 MPa to form dense tablets. The pressed material is then melted in an electric arc melting furnace. At high temperature, molybdenum and carbon react to generate Mo2C. The reaction equation is: 2Mo + 3C → Mo2C + C. During this process, carbon may exist in part in the form of graphite, forming carbides with molybdenum.

[0027] S2 involves mixing, grinding, and calcining the aforementioned Mo2C matrix with boric acid. At high temperature, the boric acid decomposes and incorporates into the Mo2C, forming boron-doped molybdenum carbide. Boron doping improves the material's hardness and thermal stability. The boric acid decomposition reaction is: H3BO3 → B2O3 + 3H2O

[0028] S3 boron-doped molybdenum carbide was dispersed in an ethanol-water solution. Ammonia and tetraethyl orthosilicate were added, and the mixture was heated and stirred. The ammonia provided an alkaline environment, and the tetraethyl orthosilicate hydrolyzed to form silica, which coated the surface of the boron-doped molybdenum carbide, enhancing its dispersibility and stability in the medium. The silica coating reaction was: Si(OC2H5)4 + 4H2O → SiO2 + 4C2H5OH. Surface modification was achieved by adding N-(6-aminohexyl)aminomethyltriethoxysilane. The silane coupling agent formed covalent bonds with the silica surface and simultaneously provided amino functional groups, enhancing the interfacial activity and adhesion of the material.

[0029] Preferably, the method for preparing the modified boron-doped molybdenum carbide includes the following steps:

[0030] S1. Molybdenum powder and carbon powder are uniformly mixed in a mass ratio of (1.2-2.5):1. 8-16 wt% of anhydrous ethanol is added to the mixture. After grinding for 0.5-2 hours, the mixture is pressed into tablets at 120-180 MPa for 2-6 minutes and then melted in an electric arc furnace with a current of 400-800 A for 1-5 minutes to obtain the Mo2C matrix.

[0031] S2 At room temperature, 8-14 parts by weight of the above Mo2C matrix and 2-5 parts by weight of boric acid are ground together for 20-60 min, then placed in a tube furnace under nitrogen atmosphere at 800-900℃ for 2-5 h, cooled to room temperature, washed with 3-5 mol / L NaOH aqueous solution, filtered and dried to obtain boron-doped molybdenum carbide.

[0032] S3. Disperse 5-10 parts by weight of the above boron-doped molybdenum carbide in 80-160 parts by weight of 55-65 wt% ethanol aqueous solution, stir evenly, add 1-3 parts by weight of ammonia water and 0.5-2 parts by weight of tetraethyl orthosilicate, stir and react at 45-60℃ and 400-700 rpm for 4-8 h, filter, wash and dry to obtain silica-coated boron-doped molybdenum carbide; add 0.5-2 parts by weight of N-(6-aminohexyl)aminomethyltriethoxysilane, stir at 40-55℃ and 500-700 rpm for 1-3 h, centrifuge, wash and dry to obtain modified boron-doped molybdenum carbide.

[0033] A zirconia ceramic material is obtained by any of the above preparation methods.

[0034] The beneficial effects of this invention are as follows: 1. This invention provides a zirconia ceramic material and its preparation method. By adding a dispersant, the aggregation and sedimentation of zirconia and other solid particles can be effectively prevented, thereby improving the dispersion stability of the entire system. This facilitates uniform physical and chemical changes during the subsequent calcination process, resulting in a uniform microstructure and better material properties. It also reduces the risk of porosity and crack defects caused by particle aggregation during calcination, thereby improving the compact packing of the ceramic material and helping to optimize grain growth. This results in a finer and more uniform grain structure, improving the strength, toughness, and compactness of the ceramic material.

[0035] 2. By adding modified boron-doped molybdenum carbide, the hardness and wear resistance of zirconia ceramics can be improved. This can promote grain refinement in zirconia ceramics and enhance the interfacial bonding between different phases, thereby improving the uniformity and mechanical properties of the material. It also helps to improve the wear resistance and structural stability of the material.

[0036] 3. The preparation method of this invention is simple and low in cost, effectively reducing defects that occur during sintering. The prepared zirconia ceramic material has good mechanical properties, dense structure, and good wear resistance. Detailed Implementation

[0037] The invention will now be described in further detail with reference to specific embodiments, but it should not be construed as limiting the scope of the invention to the following embodiments.

[0038] Description of some raw materials in this application:

[0039] The carbon nanotubes were purchased from Guangzhou Jiushun New Materials Co., Ltd., grade CN301C3.

[0040] The polyvinyl alcohol was purchased from Wuhan Runxingyuan Technology Co., Ltd., model PVA1788.

[0041] The molybdenum powder was purchased from Qinghe County Xingxin New Material Technology Co., Ltd., with a mesh size of 5000 mesh.

[0042] The toner was purchased from Dongguan Longhuang Plastic Raw Materials Co., Ltd., brand name KD000EI.

[0043] Commercially available molybdenum carbide was purchased from Hebei Teng Shuang Metal Materials Co., Ltd., 8000 mesh.

[0044] Example 1

[0045] A method for preparing a zirconia ceramic material includes the following steps:

[0046] Step 1: Mixing: Mix 80 parts by weight of zirconium oxide, 8 parts by weight of modified boron-doped molybdenum carbide, 2 parts by weight of carbon nanotubes, 3 parts by weight of cerium oxide, 7 parts by weight of dispersant, and 100 parts by weight of 50 wt% ethanol aqueous solution to obtain a mixture; place the mixture in a ball mill for ball milling at a ball milling rate of 200 r / min for 3 h to obtain a ball-milled mixture;

[0047] Step 2, Molding: The ball milled mixture is used to form a wet blank by slip casting, and then a hydraulic press is used to press the wet blank into shape. The pressure is 220 PPa and the pressing time is 5 minutes to obtain a green blank.

[0048] Step 3: Processing: The green body is machined to obtain a zirconia ceramic green body;

[0049] Step 4: Sintering: The above-mentioned zirconia ceramic blank is sintered at a constant temperature of 1650℃ for 5 hours under vacuum. After natural cooling to room temperature, it is ground and polished to obtain zirconia ceramic material.

[0050] The dispersant is composed of hydroxypropyl methylcellulose and polyvinyl alcohol in a mass ratio of 1:1.8.

[0051] The method for preparing the modified boron-doped molybdenum carbide includes the following steps:

[0052] S1. Molybdenum powder and carbon powder are uniformly mixed in a mass ratio of 2:1. 10 wt% anhydrous ethanol of the molybdenum powder is added. After grinding for 1 hour, the mixture is pressed into tablets at 150 MPa for 4 minutes and then placed in an electric arc melting furnace for melting. The current is 500 A and the melting time is 3 minutes to obtain the Mo2C matrix.

[0053] S2 At room temperature, 10 parts by weight of the above Mo2C matrix and 3 parts by weight of boric acid were ground together for 30 min, and then calcined in a tube furnace under nitrogen atmosphere at 850℃ for 3 h. After cooling to room temperature, the matrix was washed with 4 mol / L NaOH aqueous solution, filtered and dried to obtain boron-doped molybdenum carbide.

[0054] S3 dispersed 8 parts by weight of the above boron-doped molybdenum carbide in 100 parts by weight of 60 wt% ethanol aqueous solution, stirred evenly, added 2 parts by weight of ammonia water and 1 part by weight of tetraethyl orthosilicate, stirred at 50℃ and 600 rpm for 6 h, filtered, washed and dried to obtain silica-coated boron-doped molybdenum carbide; added 1 part by weight of N-(6-aminohexyl)aminomethyltriethoxysilane, stirred at 50℃ and 600 rpm for 2 h, centrifuged, washed and dried to obtain modified boron-doped molybdenum carbide.

[0055] Example 2

[0056] A method for preparing a zirconia ceramic material includes the following steps:

[0057] Step 1: Mixing: Mix 60 parts by weight of zirconium oxide, 5 parts by weight of modified boron-doped molybdenum carbide, 1 part by weight of carbon nanotubes, 2 parts by weight of cerium oxide, 5 parts by weight of dispersant, and 800 parts by weight of 40wt% ethanol aqueous solution to obtain a mixture; place the mixture in a ball mill for ball milling at a ball milling rate of 160 r / min for 2 h to obtain a ball-milled mixture;

[0058] Step 2, Molding: The ball milling mixture is used to obtain a wet blank by slip casting, and then the wet blank is pressed into shape by a hydraulic press at a pressure of 180 PPa for 3 minutes to obtain a green blank;

[0059] Step 3: Processing: The green body is machined to obtain a zirconia ceramic green body;

[0060] Step 4: Sintering: The above-mentioned zirconia ceramic blank is sintered at a constant temperature of 1500℃ for 3 hours in a vacuum environment, and then naturally cooled to room temperature. After grinding and polishing, the zirconia ceramic material is obtained.

[0061] The dispersant is composed of hydroxypropyl methylcellulose and polyvinyl alcohol in a mass ratio of 1:1.2.

[0062] The method for preparing the modified boron-doped molybdenum carbide includes the following steps:

[0063] S1. Molybdenum powder and carbon powder are uniformly mixed in a mass ratio of 1.2:1. 8 wt% anhydrous ethanol of the molybdenum powder is added. After grinding for 0.5 h, the mixture is pressed into tablets at 120 MPa for 2 min and then melted in an electric arc melting furnace with a current of 400 A and a melting time of 1 min to obtain Mo2C matrix.

[0064] S2 At room temperature, 8 parts by weight of the above Mo2C matrix and 2 parts by weight of boric acid were ground together for 20 min, then placed in a tube furnace under nitrogen atmosphere at 800℃ for 2 h, cooled to room temperature, washed with 3 mol / L NaOH aqueous solution, filtered and dried to obtain boron-doped molybdenum carbide;

[0065] S3 dispersed 5 parts by weight of the above boron-doped molybdenum carbide in 80 parts by weight of 55 wt% ethanol aqueous solution, stirred evenly, added 1 part by weight of ammonia water and 0.5 parts by weight of tetraethyl orthosilicate, stirred at 45℃ and 400 rpm for 4 h, filtered, washed and dried to obtain silica-coated boron-doped molybdenum carbide; added 0.5 parts by weight of N-(6-aminohexyl)aminomethyltriethoxysilane, stirred at 40℃ and 500 rpm for 1 h, centrifuged, washed and dried to obtain modified boron-doped molybdenum carbide.

[0066] Example 3

[0067] A method for preparing a zirconia ceramic material includes the following steps:

[0068] Step 1: Mixing: Mix 100 parts by weight of zirconium oxide, 12 parts by weight of modified boron-doped molybdenum carbide, 3 parts by weight of carbon nanotubes, 5 parts by weight of cerium oxide, 10 parts by weight of dispersant, and 150 parts by weight of 60 wt% ethanol aqueous solution to obtain a mixture; place the mixture in a ball mill for ball milling at a ball milling rate of 240 r / min for 5 h to obtain a ball-milled mixture;

[0069] Step 2, Molding: The ball milling mixture is used to obtain a wet blank by slip casting, and then the wet blank is pressed into shape by a hydraulic press at a pressure of 260 PPa for 7 minutes to obtain a green blank;

[0070] Step 3: Processing: The green body is machined to obtain a zirconia ceramic green body;

[0071] Step 4: Sintering: The above-mentioned zirconia ceramic blank is sintered at 1800℃ for 6 hours in a vacuum environment, and then naturally cooled to room temperature. After grinding and polishing, the zirconia ceramic material is obtained.

[0072] The dispersant is composed of hydroxypropyl methylcellulose and polyvinyl alcohol in a mass ratio of 1:2.5.

[0073] The method for preparing the modified boron-doped molybdenum carbide includes the following steps:

[0074] S1. Molybdenum powder and carbon powder are uniformly mixed in a mass ratio of 2.5:1. 16 wt% of anhydrous ethanol is added to the molybdenum powder. After grinding for 2 hours, the mixture is pressed into tablets at 180 MPa for 6 minutes and then melted in an electric arc melting furnace with a current of 800 A and a melting time of 5 minutes to obtain Mo2C matrix.

[0075] S2 At room temperature, 14 parts by weight of the above Mo2C matrix and 5 parts by weight of boric acid were ground together for 60 min, and then calcined in a tube furnace under nitrogen atmosphere at 900℃ for 5 h. After cooling to room temperature, the matrix was washed with 5 mol / L NaOH aqueous solution, filtered and dried to obtain boron-doped molybdenum carbide.

[0076] S3 dispersed 10 parts by weight of the above boron-doped molybdenum carbide in 160 parts by weight of 65 wt% ethanol aqueous solution, stirred evenly, added 3 parts by weight of ammonia water and 2 parts by weight of tetraethyl orthosilicate, stirred at 60℃ and 700 rpm for 8 h, filtered, washed and dried to obtain silica-coated boron-doped molybdenum carbide; added 2 parts by weight of N-(6-aminohexyl)aminomethyltriethoxysilane, stirred at 55℃ and 700 rpm for 3 h, centrifuged, washed and dried to obtain modified boron-doped molybdenum carbide.

[0077] Comparative Example 1

[0078] A method for preparing a zirconia ceramic material includes the following steps:

[0079] Step 1: Mixing: Mix 80 parts by weight of zirconium oxide, 8 parts by weight of molybdenum carbide, 2 parts by weight of carbon nanotubes, 3 parts by weight of cerium oxide, 7 parts by weight of dispersant, and 100 parts by weight of 50 wt% ethanol aqueous solution to obtain a mixture; place the mixture in a ball mill for ball milling at a ball milling rate of 200 r / min for 3 h to obtain a ball-milled mixture;

[0080] Step 2, Molding: The ball milled mixture is used to form a wet blank by slip casting, and then a hydraulic press is used to press the wet blank into shape. The pressure is 220 PPa and the pressing time is 5 minutes to obtain a green blank.

[0081] Step 3: Processing: The green body is machined to obtain a zirconia ceramic green body;

[0082] Step 4: Sintering: The above-mentioned zirconia ceramic blank is sintered at a constant temperature of 1650℃ for 5 hours under vacuum. After natural cooling to room temperature, it is ground and polished to obtain zirconia ceramic material.

[0083] The dispersant is composed of hydroxypropyl methylcellulose and polyvinyl alcohol in a mass ratio of 1:1.8.

[0084] The molybdenum carbide used is commercially available molybdenum carbide.

[0085] Comparative Example 2

[0086] A method for preparing a zirconia ceramic material includes the following steps:

[0087] Step 1: Mixing: Mix 80 parts by weight of zirconium oxide, 8 parts by weight of boron-doped molybdenum carbide, 2 parts by weight of carbon nanotubes, 3 parts by weight of cerium oxide, 7 parts by weight of dispersant, and 100 parts by weight of 50 wt% ethanol aqueous solution to obtain a mixture; place the mixture in a ball mill for ball milling at a ball milling rate of 200 r / min for 3 h to obtain a ball-milled mixture;

[0088] Step 2, Molding: The ball milled mixture is used to form a wet blank by slip casting, and then a hydraulic press is used to press the wet blank into shape. The pressure is 220 PPa and the pressing time is 5 minutes to obtain a green blank.

[0089] Step 3: Processing: The green body is machined to obtain a zirconia ceramic green body;

[0090] Step 4: Sintering: The above-mentioned zirconia ceramic blank is sintered at a constant temperature of 1650℃ for 5 hours under vacuum. After natural cooling to room temperature, it is ground and polished to obtain zirconia ceramic material.

[0091] The dispersant is composed of hydroxypropyl methylcellulose and polyvinyl alcohol in a mass ratio of 1:1.8.

[0092] The method for preparing boron-doped molybdenum carbide includes the following steps:

[0093] S1. Molybdenum powder and carbon powder are uniformly mixed in a mass ratio of 2:1. 10 wt% anhydrous ethanol of the molybdenum powder is added. After grinding for 1 hour, the mixture is pressed into tablets at 150 MPa for 4 minutes and then placed in an electric arc melting furnace for melting. The current is 500 A and the melting time is 3 minutes to obtain the Mo2C matrix.

[0094] S2 At room temperature, 10 parts by weight of the above Mo2C matrix and 3 parts by weight of boric acid were ground together for 30 min, then placed in a tube furnace under nitrogen atmosphere at 850℃ for 3 h, cooled to room temperature, washed with 4 mol / L NaOH aqueous solution, filtered and dried to obtain boron-doped molybdenum carbide.

[0095] Comparative Example 3

[0096] A method for preparing a zirconia ceramic material includes the following steps:

[0097] Step 1: Mixing: Mix 80 parts by weight of zirconium oxide, 8 parts by weight of modified boron-doped molybdenum carbide, 2 parts by weight of carbon nanotubes, 3 parts by weight of cerium oxide, 7 parts by weight of dispersant, and 100 parts by weight of 50 wt% ethanol aqueous solution to obtain a mixture; place the mixture in a ball mill for ball milling at a ball milling rate of 200 r / min for 3 h to obtain a ball-milled mixture;

[0098] Step 2, Molding: The ball milled mixture is used to form a wet blank by slip casting, and then a hydraulic press is used to press the wet blank into shape. The pressure is 220 PPa and the pressing time is 5 minutes to obtain a green blank.

[0099] Step 3: Processing: The green body is machined to obtain a zirconia ceramic green body;

[0100] Step 4: Sintering: The above-mentioned zirconia ceramic blank is sintered at a constant temperature of 1650℃ for 5 hours under vacuum. After natural cooling to room temperature, it is ground and polished to obtain zirconia ceramic material.

[0101] The dispersant is hydroxypropyl methylcellulose.

[0102] The method for preparing the modified boron-doped molybdenum carbide includes the following steps:

[0103] S1. Molybdenum powder and carbon powder are uniformly mixed in a mass ratio of 2:1. 10 wt% anhydrous ethanol of the molybdenum powder is added. After grinding for 1 hour, the mixture is pressed into tablets at 150 MPa for 4 minutes and then placed in an electric arc melting furnace for melting. The current is 500 A and the melting time is 3 minutes to obtain the Mo2C matrix.

[0104] S2 At room temperature, 10 parts by weight of the above Mo2C matrix and 3 parts by weight of boric acid were ground together for 30 min, and then calcined in a tube furnace under nitrogen atmosphere at 850℃ for 3 h. After cooling to room temperature, the matrix was washed with 4 mol / L NaOH aqueous solution, filtered and dried to obtain boron-doped molybdenum carbide.

[0105] S3 dispersed 8 parts by weight of the above boron-doped molybdenum carbide in 100 parts by weight of 60 wt% ethanol aqueous solution, stirred evenly, added 2 parts by weight of ammonia water and 1 part by weight of tetraethyl orthosilicate, stirred at 50℃ and 600 rpm for 6 h, filtered, washed and dried to obtain silica-coated boron-doped molybdenum carbide; added 1 part by weight of N-(6-aminohexyl)aminomethyltriethoxysilane, stirred at 50℃ and 600 rpm for 2 h, centrifuged, washed and dried to obtain modified boron-doped molybdenum carbide.

[0106] Comparative Example 4

[0107] A method for preparing a zirconia ceramic material includes the following steps:

[0108] Step 1: Mixing: Mix 80 parts by weight of zirconium oxide, 8 parts by weight of modified boron-doped molybdenum carbide, 2 parts by weight of carbon nanotubes, 3 parts by weight of cerium oxide, 7 parts by weight of dispersant, and 100 parts by weight of 50 wt% ethanol aqueous solution to obtain a mixture; place the mixture in a ball mill for ball milling at a ball milling rate of 200 r / min for 3 h to obtain a ball-milled mixture;

[0109] Step 2, Molding: The ball milled mixture is used to form a wet blank by slip casting, and then a hydraulic press is used to press the wet blank into shape. The pressure is 220 PPa and the pressing time is 5 minutes to obtain a green blank.

[0110] Step 3: Processing: The green body is machined to obtain a zirconia ceramic green body;

[0111] Step 4: Sintering: The above-mentioned zirconia ceramic blank is sintered at a constant temperature of 1650℃ for 5 hours under vacuum. After natural cooling to room temperature, it is ground and polished to obtain zirconia ceramic material.

[0112] The dispersant is polyvinyl alcohol.

[0113] The method for preparing the modified boron-doped molybdenum carbide includes the following steps:

[0114] S1. Molybdenum powder and carbon powder are uniformly mixed in a mass ratio of 2:1. 10 wt% anhydrous ethanol of the molybdenum powder is added. After grinding for 1 hour, the mixture is pressed into tablets at 150 MPa for 4 minutes and then placed in an electric arc melting furnace for melting. The current is 500 A and the melting time is 3 minutes to obtain the Mo2C matrix.

[0115] S2 At room temperature, 10 parts by weight of the above Mo2C matrix and 3 parts by weight of boric acid were ground together for 30 min, and then calcined in a tube furnace under nitrogen atmosphere at 850℃ for 3 h. After cooling to room temperature, the matrix was washed with 4 mol / L NaOH aqueous solution, filtered and dried to obtain boron-doped molybdenum carbide.

[0116] S3 dispersed 8 parts by weight of the above boron-doped molybdenum carbide in 100 parts by weight of 60 wt% ethanol aqueous solution, stirred evenly, added 2 parts by weight of ammonia water and 1 part by weight of tetraethyl orthosilicate, stirred at 50℃ and 600 rpm for 6 h, filtered, washed and dried to obtain silica-coated boron-doped molybdenum carbide; added 1 part by weight of N-(6-aminohexyl)aminomethyltriethoxysilane, stirred at 50℃ and 600 rpm for 2 h, centrifuged, washed and dried to obtain modified boron-doped molybdenum carbide.

[0117] Test Example 1

[0118] 1. Bending strength test: The three-point bending strength of the zirconia ceramic material prepared in this invention was determined according to the national standard GB / T6569-2006 "Test Method for Bending Strength of Fine Ceramics". The sample size was 40×3×4mm, the span was 30mm, the loading speed was 0.5mm / min, and the upper and lower rollers were kept clean and free of serious scratches. The lower roller needed to be contoured according to the finished product. Five replicates were made for each group of samples, and the average value was taken. The results are shown in Table 1.

[0119] 2. Vickers hardness: The Vickers hardness of the zirconia ceramic material prepared in this invention was determined using the test method in the national standard QB / T4780-2015 "Method for Determination of Vickers Hardness of Glaze on Daily-use Ceramic Ware". Five replicates were made for each sample group, and the average value was taken. The results are shown in Table 1.

[0120] Table 1. Test results of mechanical properties of zirconia ceramic materials

[0121]

[0122] Test Example 2

[0123] Wear resistance test: The wear resistance of the zirconia ceramic material prepared above was tested in accordance with the national standard "GT / T3810.7-2016 Ceramic Tile Test Methods Part 7: Determination of Abrasion Resistance of Glazed Tile Surface". The method described was to grind at 12,000 revolutions per minute. The mass loss of the zirconia ceramic material prepared after firing under the same firing conditions is shown in Table 2 below.

[0124] Table 2. Test results of wear resistance of zirconia ceramic materials

[0125]

[0126]

[0127] The results above show that the zirconia ceramic material prepared by this invention has good mechanical properties. As can be seen from Example 1 and Comparative Examples 3-4, when hydroxypropyl methylcellulose and polyvinyl alcohol are used in combination, they can work together using their different dispersion mechanisms to more effectively prevent the aggregation and sedimentation of zirconia and other solid particles, thereby improving the dispersion stability of the entire system. This facilitates uniform physical and chemical changes during the subsequent calcination process, resulting in a uniform microstructure and better material properties. It also reduces the risk of porosity and crack defects caused by particle aggregation during calcination, leading to a denser packing of the ceramic material. This helps optimize grain growth, resulting in a finer and more uniform grain structure, and improving the strength, toughness, and density of the ceramic material.

[0128] As can be seen from Examples 1 and Comparative Examples 1-2, boron doping can alter the microstructure of molybdenum carbide, increasing its toughness. Modified boron-doped molybdenum carbide is a hard material; its addition can improve the hardness and wear resistance of zirconia ceramics, promote grain refinement in zirconia ceramics, and enhance interfacial bonding between different phases, thereby improving the material's uniformity and mechanical properties. It also helps improve the material's wear resistance and structural stability. Furthermore, the addition of modified boron-doped molybdenum carbide helps optimize the sintering process, potentially lowering the sintering temperature and increasing the sintering rate, thus saving energy and reducing production costs.

[0129] The introduction of silane coupling agents improves the dispersion of boron-doped molybdenum carbide in zirconia ceramic matrices, reducing particle aggregation and resulting in a more uniform microstructure, which helps improve the material's density and strength. Modified boron-doped molybdenum carbide acts as a nucleus for grain boundary formation during calcination, promoting grain growth and grain boundary formation; the increased number of grain boundaries enhances the material's strength and toughness. During calcination, silane-modified boron-doped molybdenum carbide reacts chemically with the surface of zirconia particles in the ceramic, forming strong chemical bonds. This enhanced interparticle bonding strengthens the overall compactness of the ceramic material. Furthermore, during calcination, silane coupling agents reduce porosity and defects in the ceramic material. Because silane coupling agents increase interparticle bonding, they facilitate gas expulsion and seal of micropores during sintering, thereby reducing porosity, improving material density, and enhancing wear resistance.

Claims

1. A method for preparing a zirconia ceramic material, characterized in that, Includes the following steps: Step 1, Mixing: Mix 60-100 parts by weight of zirconium oxide, 5-12 parts by weight of modified boron-doped molybdenum carbide, 1-3 parts by weight of carbon nanotubes, 2-5 parts by weight of cerium oxide, 5-10 parts by weight of dispersant, and 80-150 parts by weight of 40-60 wt% ethanol aqueous solution to obtain a mixture; ball mill the mixture to obtain a ball-milled mixture; Step 2, Shaping: The ball mill mixture is used to obtain a wet blank by slip casting, and then a hydraulic press is used to press the wet blank into shape to obtain a green blank; Step 3: Processing: The green body is machined to obtain a zirconia ceramic green body; Step 4: Sintering: The above-mentioned zirconia ceramic blank is sintered to obtain zirconia ceramic material; The dispersant is composed of hydroxypropyl methylcellulose and polyvinyl alcohol in a mass ratio of 1:(1.2-2.5); The modified boron-doped molybdenum carbide is prepared by the following steps: S1. Molybdenum powder and carbon powder are uniformly mixed, anhydrous ethanol is added, the mixture is ground, pressed into tablets, and melted to obtain the Mo2C matrix. S2 grinds the above Mo2C matrix with boric acid, then calcines it in a tube furnace, cools it to room temperature, washes it, filters it, and dries it to obtain boron-doped molybdenum carbide. S3 disperses the above boron-doped molybdenum carbide in an aqueous ethanol solution, stirs until homogeneous, adds ammonia and tetraethyl orthosilicate and stirs to react, filters, washes and dries to obtain silica-coated boron-doped molybdenum carbide; adds N-(6-aminohexyl)aminomethyltriethoxysilane and stirs to obtain modified boron-doped molybdenum carbide.

2. The method for preparing zirconia ceramic material as described in claim 1, characterized in that, The ball milling rate in step one is 160-240 r / min, and the ball milling time is 2-5 h.

3. The method for preparing zirconia ceramic material as described in claim 1, characterized in that, The pressing pressure in step two is 180-260 MPa, and the pressing time is 3-7 minutes.

4. The method for preparing zirconia ceramic material as described in claim 1, characterized in that, The sintering temperature in step four is 1500-1800℃, and the sintering time is 3-6 hours.

5. The method for preparing zirconia ceramic material as described in claim 1, characterized in that, In S1, the tableting pressure is 120-180MPa, the tableting time is 2-6min, the melting current is 400-800A, and the melting time is 1-5min.

6. The method for preparing zirconia ceramic material as described in claim 1, characterized in that, The calcination temperature in S2 is 800-900℃, and the calcination time is 2-5h.

7. The method for preparing zirconia ceramic material as described in claim 1, characterized in that, The heating and stirring temperature in S3 is 45-60℃, the stirring speed is 400-700rpm, and the stirring time is 4-8h.

8. A zirconia ceramic material, characterized in that, It is prepared by the preparation method described in any one of claims 1-7.

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