A high-strength wear-resistant silicon nitride bonded silicon carbide ceramic and its preparation method

Abstract

The present invention relates to the technical field of wear-resistant ceramics, and in particular to a high-strength, wear-resistant silicon nitride-bonded silicon carbide ceramic and a preparation method thereof. The high-strength, wear-resistant silicon nitride-bonded silicon carbide ceramic is prepared from elemental silicon powder, silicon carbide powder, silicon nitride powder, a tempering agent, and a binder: the tempering agent includes Y2O3 micro-nano particles, zirconium carbide powder, zirconium powder, and tungsten carbide. A reaction-sintered silicon nitride-bonded silicon carbide process is employed, and the microstructure and phase composition are optimized and controllably prepared under the coupling effect of a composite tempering agent and in-situ generated controllable fibrous and columnar Si3N4. ZrSi2N4 can form a good chemical bond with silicon nitride. The wear-resistant ceramic prepared by this method has the characteristics of high strength, high hardness, and high toughness, with significantly improved wear resistance, corrosion resistance, and impact resistance, extended service life, and greatly improved production efficiency in related industries. At the same time, pollution to materials is reduced, ensuring the high performance and stability of the product, and having significant economic benefits.

Description

Technical Field

[0001] This invention relates to the field of wear-resistant ceramics technology, and in particular to a high-strength wear-resistant silicon nitride-bonded silicon carbide ceramic and its preparation method. Background Technology

[0002] Wear-resistant materials are widely used in various fields of industrial production. With the rapid development of science and technology and modern industry, the development of wear-resistant materials has become an important factor affecting the efficiency of modern industrial production.

[0003] In powder production, wear-resistant materials are used throughout the entire process, from raw material mining, crushing, grinding, and ultrafine grinding of micro and nano powders. The performance of these materials directly determines the cost and quality of powder processing. Modern industrial systems have an increasing demand for micro and nano powders, placing higher demands on grinding technologies. For example, in planetary ball mills, the grinding jar and grinding balls are the components that directly contact the material during the powdering process. Their main materials include high-chromium alloys, medium-high carbon steel, and agate. It is difficult to achieve a balance between the mechanical toughness, impact resistance, and wear resistance of these metal materials. When grinding high-hardness materials, spalling and breakage are prone to occur, not only shortening the service life but also causing contamination of the material from the spalled metal. Natural agate is expensive and difficult to manufacture into large-volume grinding jars, negatively impacting industrial production. Furthermore, wear-resistant materials are even more widely used in the metallurgical, cement, and glass industries, such as rollers in hot rolling processes, material pipes for aluminum alloy die casting, cement rotary kiln inlets, and wear-resistant pallets for glass annealing kilns. Wear-resistant materials have become a pillar of industrial production. Existing wear-resistant materials are insufficient to meet the current market production demands.

[0004] Silicon nitride-bonded silicon carbide (SiN4) is a high-performance ceramic material with Si3N4 as the main bonding phase and one or more carbides, nitrides, and oxides as reinforcing phases. It possesses excellent corrosion resistance, erosion resistance, and good comprehensive mechanical properties such as hardness, toughness, and wear resistance. Furthermore, it has a price advantage compared to other non-oxide ceramics such as recrystallized silicon carbide. Therefore, SiN4-bonded silicon carbide materials are widely used in non-ferrous metallurgy, steel smelting, petrochemicals, and automobile manufacturing. However, current production processes for SiN4-bonded silicon carbide use refractory-grade raw materials and relatively outdated mixing and molding processes, resulting in SiN4-bonded silicon carbide with poor uniformity, unsatisfactory mechanical properties, and short lifespan, making it difficult to apply in more advanced powder crushing and grinding technologies and harsher operating environments.

[0005] Therefore, we propose a high-strength, wear-resistant silicon nitride-bonded silicon carbide ceramic and its preparation method to solve the above problems. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of the prior art by proposing a high-strength and wear-resistant silicon nitride-bonded silicon carbide ceramic and its preparation method.

[0007] A high-strength, wear-resistant silicon nitride-bonded silicon carbide ceramic is prepared from the following raw materials in parts by weight:

[0008] 65-85 parts of elemental silicon powder, 15-35 parts of silicon carbide powder, 5-10 parts of silicon nitride powder, 1-5 parts of conditioning agent, and 0.5-10 parts of binder;

[0009] The conditioning agent comprises 5-10 parts by weight of Y2O3 micro / nano particles, 5-8 parts by weight of zirconium carbide powder, 5-8 parts by weight of zirconium powder, and 1-3 parts by weight of tungsten carbide.

[0010] Preferably, the particle size of the elemental silicon powder is 200-600 mesh, and the particle size of the silicon carbide powder is 200-600 mesh.

[0011] Preferably, the silicon nitride has a particle size of 600 to 1000 mesh.

[0012] Preferably, the binder is one or more selected from polyvinyl alcohol, dextrin, phenolic resin, arabic resin, lignin, phosphate and hydroxymethyl cellulose.

[0013] A method for preparing high-strength, wear-resistant silicon nitride-bonded silicon carbide ceramics includes the following steps:

[0014] S1. Add the raw materials, anhydrous ethanol, and grinding balls to a high-speed mixer and premix for 15 min to 12 h. Then add 5 to 50% of the raw material mass of claim 1 with deionized water and place it in a high-speed ball mill for 15 min to 12 h to obtain a slurry.

[0015] S2. The slurry obtained in step S1 is dried at 100-300℃ using a spray granulation device to obtain granules with uniform and stable dispersion and a particle size of 0.01-1.5mm.

[0016] S3. The granulated material obtained in step S2 is first put into an extrusion molding machine and extruded to obtain a ceramic green body. Then, the ceramic green body obtained by extrusion molding is subjected to isostatic pressing to obtain a uniform and dense ceramic green body.

[0017] S4. Place the ceramic tube blank obtained in step S3 in a high-temperature atmosphere sintering furnace, heat it to 800-1000℃ at a heating rate of 10-30℃ / min under a nitrogen atmosphere, hold it for 0.5-3h, then heat it to 1200-1400℃ at a heating rate of 10-30℃ / min, hold it for 1-3h, and then heat it to 1500-1700℃ at a heating rate of 10-30℃ / min, hold it for 3-6h to obtain a high-strength, wear-resistant silicon nitride-bonded silicon carbide ceramic.

[0018] Preferably, in step S1, the high-speed ball mill rotates at a speed of 100 r / min to 360 r / min, the grinding balls are one or more of agate grinding balls, stainless steel grinding balls, and corundum grinding balls, with a particle size of 1 to 10 mm, and the protective atmosphere is vacuum, argon, nitrogen, or a combination thereof.

[0019] Preferably, in step S1, the mass ratio of raw materials, anhydrous ethanol, and grinding balls is 1:4 to 8:2 to 6.

[0020] Preferably, in step S2, after the granulated material is dried, it is sealed and trapped at a temperature of 28–32°C for 12–36 hours.

[0021] Preferably, in step S3, the isostatic pressure is 150-200 MPa.

[0022] The beneficial effects of this invention are:

[0023] 1. This invention utilizes a high-solids slurry spray granulation process, which can uniformly mix components with significantly different contents in the raw materials, thereby ensuring that the composition and structure of each part of the product are uniform and consistent.

[0024] 2. This invention employs a composite molding process, which improves the density and uniformity of ceramics, enhances the overall mechanical properties and thermal shock stability of the product, significantly reduces raw material consumption caused by machining, and substantially increases product profits for manufacturing enterprises.

[0025] 3. The wear-resistant ceramics prepared by this method, under a nitrogen atmosphere, utilize a conditioning agent such as Y₂O₃ to dissolve α-Si₃N₄ in a liquid phase and promote the growth of β-Si₃N₄, resulting in the in-situ formation of fibrous and columnar silicon nitride crystals within the material. Simultaneously, under high temperature and pressure, ZrSi₂N₄, possessing ultra-high hardness, high thermal stability, and corrosion resistance, is generated in situ, forming a good chemical bond with silicon nitride. Furthermore, through coupling with the composite conditioning agent, the silicon nitride-bonded silicon carbide ceramic exhibits high strength, high hardness, and high toughness in all directions. The controllable microstructure and phase composition provide high adaptability to different shapes and service environments, significantly improving wear resistance, corrosion resistance, and impact resistance. It can withstand rapid continuous impact, high-hardness materials, and corrosive materials (atmospheres), increasing continuous working time and greatly improving the production efficiency of ultrafine powders while reducing material contamination, ensuring high product performance and stability, and demonstrating significant economic benefits. Detailed Implementation

[0026] The present invention will be further explained below with reference to specific embodiments.

[0027] Example 1:

[0028] A high-strength, wear-resistant silicon nitride-bonded silicon carbide ceramic is prepared from the following raw materials in parts by weight:

[0029] 75 parts by weight of elemental silicon powder with a particle size of 400 mesh, 25 parts by weight of silicon carbide powder with a particle size of 400 mesh, 5 parts by weight of silicon nitride powder with a particle size of 800 mesh, 2 parts by weight of conditioning agent, and 3 parts by weight of phenolic resin binder.

[0030] The conditioning agent includes 8 parts by weight of Y2O3 micro / nano particles, 6 parts by weight of zirconium carbide powder, 6 parts by weight of zirconium powder, and 2 parts by weight of tungsten carbide.

[0031] A method for preparing high-strength, wear-resistant silicon nitride-bonded silicon carbide ceramics includes the following steps:

[0032] S1. Weigh the raw materials, anhydrous ethanol, and 5mm grinding balls accurately according to a mass ratio of 1:6:4. Add them to a high-speed mixer and premix for 45 minutes. Then add 30% of the raw material mass of deionized water and place it in a high-speed ball mill at 200r / min. Ball mill for 45 minutes under a nitrogen atmosphere to obtain a slurry. The grinding balls are agate grinding beads.

[0033] S2. The slurry obtained in step S1 is dried at 200°C using a spray granulation device to obtain a uniformly dispersed, stable, and consistent granulated material with a particle size of 0.5 mm. Then, the material is sealed and trapped at 30°C for 24 hours.

[0034] S3. The granulated material obtained in step S2 is first put into an extrusion molding machine and extruded to obtain a ceramic green body. Then, the ceramic green body obtained by extrusion molding is isostatically pressed under a pressure of 180MPa to obtain a uniform and dense ceramic green body.

[0035] S4. Place the ceramic tube blank obtained in step S3 in a high-temperature atmosphere sintering furnace, heat it to 900℃ at a heating rate of 20℃ / min under nitrogen atmosphere, hold it for 2 hours, then heat it to 1300℃ at a heating rate of 20℃ / min, hold it for 2 hours, and then heat it to 1600℃ at a heating rate of 20℃ / min, hold it for 5 hours to obtain high-strength wear-resistant silicon nitride bonded silicon carbide ceramic.

[0036] Example 2:

[0037] A high-strength, wear-resistant silicon nitride-bonded silicon carbide ceramic is prepared from the following raw materials in parts by weight:

[0038] 70 parts by weight of elemental silicon powder with a particle size of 400 mesh, 30 parts by weight of silicon carbide powder with a particle size of 400 mesh, 5 parts by weight of silicon nitride powder with a particle size of 800 mesh, 3 parts by weight of conditioning agent, and 2 parts by weight of polyvinyl alcohol binder.

[0039] The conditioning agent includes 6 parts by weight of Y2O3 micro / nano particles, 7 parts by weight of zirconium carbide powder, 7 parts by weight of zirconium powder, and 2 parts by weight of tungsten carbide.

[0040] A method for preparing high-strength, wear-resistant silicon nitride-bonded silicon carbide ceramics includes the following steps:

[0041] S1. Weigh the raw materials, anhydrous ethanol, and 5mm grinding balls accurately according to a mass ratio of 1:6:4. Add them to a high-speed mixer and premix for 45 minutes. Then add 35% of the raw material mass of deionized water and place it in a high-speed ball mill at 200r / min. Ball mill for 45 minutes under an argon atmosphere to obtain a slurry. The grinding balls are stainless steel grinding beads.

[0042] S2. The slurry obtained in step S1 is dried at 200°C using a spray granulation device to obtain a uniformly dispersed, stable, and consistent granulated material with a particle size of 1 mm. Then, the material is sealed and trapped at 30°C for 24 hours.

[0043] S3. The granulated material obtained in step S2 is first put into an extrusion molding machine and extruded to obtain a ceramic green body. Then, the ceramic green body obtained by extrusion molding is isostatically pressed under a pressure of 180MPa to obtain a uniform and dense ceramic green body.

[0044] S4. Place the ceramic tube blank obtained in step S3 in a high-temperature atmosphere sintering furnace, heat it to 1000℃ at a heating rate of 20℃ / min under a nitrogen atmosphere, hold it for 1 hour, then heat it to 1300℃ at a heating rate of 20℃ / min, hold it for 2 hours, and then heat it to 1600℃ at a heating rate of 20℃ / min, hold it for 5 hours to obtain a high-strength and wear-resistant silicon nitride-bonded silicon carbide ceramic.

[0045] Example 3:

[0046] A high-strength, wear-resistant silicon nitride-bonded silicon carbide ceramic is prepared from the following raw materials in parts by weight:

[0047] 80 parts by weight of elemental silicon powder with a particle size of 400 mesh, 20 parts by weight of silicon carbide powder with a particle size of 400 mesh, 5 parts by weight of silicon nitride powder with a particle size of 800 mesh, 4 parts by weight of conditioning agent, and 4 parts by weight of arabic resin binder.

[0048] The conditioning agent includes 6 parts by weight of Y2O3 micro / nano particles, 7 parts by weight of zirconium carbide powder, 5 parts by weight of zirconium powder, and 2 parts by weight of tungsten carbide.

[0049] A method for preparing high-strength, wear-resistant silicon nitride-bonded silicon carbide ceramics includes the following steps:

[0050] S1. Weigh the raw materials, anhydrous ethanol, and 5mm grinding balls accurately according to a mass ratio of 1:6:4. Add them to a high-speed mixer and premix for 45 minutes. Then add 30% of the raw material mass of deionized water and place it in a high-speed ball mill at 200r / min. Ball mill under a nitrogen atmosphere for 45 minutes to obtain a slurry. The grinding balls are corundum grinding beads.

[0051] S2. The slurry obtained in step S1 is dried at 200°C using a spray granulation device to obtain a uniformly dispersed, stable, and consistent granulated material with a particle size of 0.5 mm. Then, the material is sealed and trapped at 30°C for 24 hours.

[0052] S3. The granulated material obtained in step S2 is first put into an extrusion molding machine and extruded to obtain a ceramic green body. Then, the ceramic green body obtained by extrusion molding is isostatically pressed under a pressure of 180MPa to obtain a uniform and dense ceramic green body.

[0053] S4. Place the ceramic tube blank obtained in step S3 in a high-temperature atmosphere sintering furnace, heat it to 900℃ at a heating rate of 20℃ / min under a nitrogen atmosphere, hold it for 2 hours, then heat it to 1200℃ at a heating rate of 20℃ / min, hold it for 2 hours, and then heat it to 1600℃ at a heating rate of 20℃ / min, hold it for 5 hours to obtain a high-strength and wear-resistant silicon nitride-bonded silicon carbide ceramic.

[0054] Comparative example:

[0055] A silicon nitride-bonded silicon carbide tubing is prepared from the following raw materials in parts by weight:

[0056] 10 parts by weight of elemental silicon powder, 20 parts by weight of silicon nitride powder, and 20 parts by weight of silicon carbide powder.

[0057] Its preparation method includes the following steps:

[0058] S1. Mix elemental silicon powder, silicon nitride powder and silicon carbide powder at 60°C for 1.5 hours to obtain a uniform mixture;

[0059] S2. The mixture obtained in step S1 is dried at a temperature of 200℃ and a humidity of 3% for 5 hours, and then sealed and trapped for 36 hours to obtain the shaped mixture.

[0060] S3. The mixture obtained in step S2 is shaped by friction forming to obtain a blank of the tube.

[0061] S4. Place the blank of the tube obtained in step S3 into a high-temperature furnace. The high-temperature furnace is a box-type carbonization furnace. Sintering is carried out under the protection of nitrogen atmosphere. The temperature is raised to 1200℃ at a heating rate of 60℃ / h and held for 2h to obtain the tube.

[0062] The mechanical properties and thermal shock stability of the silicon nitride-bonded silicon carbide ceramic tubing in Examples 1 to 3 and the comparative example were tested, and the test results are as follows:

[0063]

[0064]

[0065] Among them, hardness is Vickers hardness at room temperature, and the testing standard is GB / T 16534-2009; coefficient of thermal expansion is the linear coefficient of thermal expansion between 20℃ and 300℃, and the testing standard is YS / T 63.4-2006; thermal shock cracking test is the residual strength retention rate after water cooling at 1000℃, and the testing standard is YB 4018-91; thermal conductivity is tested according to GB / T 39862-2021; and abrasion resistance is abrasion resistance at room temperature, and the testing standard is GB / T 18301-2012.

[0066] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A high-strength, wear-resistant silicon nitride-bonded silicon carbide ceramic, characterized in that, It is prepared from the following raw materials in parts by weight: 65-85 parts of elemental silicon powder, 15-35 parts of silicon carbide powder, 5-10 parts of silicon nitride powder, 1-5 parts of conditioning agent, and 0.5-10 parts of binder; The conditioning agent comprises 5-10 parts by weight of Y2O3 micro / nano particles, 5-8 parts by weight of zirconium carbide powder, 5-8 parts by weight of zirconium powder, and 1-3 parts by weight of tungsten carbide.

2. The high-strength, wear-resistant silicon nitride-bonded silicon carbide ceramic according to claim 1, characterized in that, The particle size of the elemental silicon powder is 200-600 mesh, and the particle size of the silicon carbide powder is 200-600 mesh.

3. The high-strength, wear-resistant silicon nitride-bonded silicon carbide ceramic according to claim 1, characterized in that, The silicon nitride has a particle size of 600-1000 mesh.

4. The high-strength, wear-resistant silicon nitride-bonded silicon carbide ceramic according to claim 1, characterized in that, The binder is one or more of polyvinyl alcohol, dextrin, phenolic resin, arabic resin, lignin, phosphate and hydroxymethyl cellulose.

5. A method for preparing high-strength, wear-resistant silicon nitride-bonded silicon carbide ceramics, characterized in that, Includes the following steps: S1. The raw material described in claim 1, anhydrous ethanol, and grinding balls are added to a high-speed mixer and premixed for 15 min to 12 h. Then, 5 to 50% of the mass of the raw material described in claim 1 is added to deionized water, and the mixture is placed in a high-speed ball mill and ball-milled for 15 min to 12 h to obtain a slurry. S2. The slurry obtained in step S1 is dried at 100-300℃ using a spray granulation device to obtain granules with uniform and stable dispersion and a particle size of 0.01-1.5mm. S3. The granulated material obtained in step S2 is first put into an extrusion molding machine and extruded to obtain a ceramic green body. Then, the ceramic green body obtained by extrusion molding is subjected to isostatic pressing to obtain a uniform and dense ceramic green body. S4. Place the ceramic tube blank obtained in step S3 in a high-temperature atmosphere sintering furnace, heat it to 800-1000℃ at a heating rate of 10-30℃ / min under a nitrogen atmosphere, hold it for 0.5-3h, then heat it to 1200-1400℃ at a heating rate of 10-30℃ / min, hold it for 1-3h, and then heat it to 1500-1700℃ at a heating rate of 10-30℃ / min, hold it for 3-6h to obtain a high-strength, wear-resistant silicon nitride-bonded silicon carbide ceramic.

6. The method for preparing a high-strength, wear-resistant silicon nitride-bonded silicon carbide ceramic according to claim 5, characterized in that, In step S1, the high-speed ball mill rotates at a speed of 100 r / min to 360 r / min, and the grinding balls are one or more of agate grinding balls, stainless steel grinding balls, and corundum grinding balls, with a particle size of 1 to 10 mm. The protective atmosphere is vacuum, argon, nitrogen, or a combination of these atmospheres.

7. The method for preparing a high-strength, wear-resistant silicon nitride-bonded silicon carbide ceramic according to claim 5, characterized in that, In step S1, the mass ratio of raw materials, anhydrous ethanol, and grinding balls is 1:4 to 8:2 to 6.

8. The method for preparing a high-strength, wear-resistant silicon nitride-bonded silicon carbide ceramic according to claim 5, characterized in that, In step S2, after the granulated material is dried, it is sealed and trapped at a temperature of 28–32°C for 12–36 hours.

9. The method for preparing a high-strength, wear-resistant silicon nitride-bonded silicon carbide ceramic according to claim 5, characterized in that, In step S3, the isostatic pressure is 150–200 MPa.