A silicon nitride bonded silicon carbide sintered ceramic material for pumps and a method for producing the same

Abstract

This invention discloses a silicon nitride-bonded silicon carbide sintered ceramic material for pumps and its preparation method. The ceramic material comprises the following raw materials in the following weight proportions: 55-70 parts silicon carbide particles; 10-15 parts silicon powder; 5-15 parts ferrosilicon-chromium alloy powder; 5-10 parts water-soluble phenolic resin powder; 5-10 parts purified water; 0.5-3 parts defoamer; 3-5 parts sintering aid; and 3-5 parts dispersant. The preparation method involves: uniformly mixing the raw materials and injecting the mixture into a mold for room temperature curing; then drying at 50-180℃ for 1-7 days before demolding; reheating to 1350-1450℃ for sintering; and finally repeating the vacuum impregnation and drying process 2-3 times to obtain the target product. The ceramic material prepared by this invention significantly improves the surface hardness of ceramic parts, thereby enhancing their wear resistance.

Description

Technical Field

[0001] This invention relates to a silicon nitride-bonded silicon carbide sintered ceramic material for pumps and its preparation method, belonging to the field of special industrial pump technology. Background Technology

[0002] With the development of modern industry, the service environment of industrial slurry pumps has become increasingly harsh. The interaction of corrosion, erosion, and cavitation reduces the service life of metal flow components in general industrial slurry pumps, making it difficult for them to meet the demands of harsh working environments. Some industrial slurry pumps use ceramic materials as flow components in the pump body. Currently, the commonly used sintered material is silicon nitride-bonded silicon carbide ceramic. Silicon nitride-bonded silicon carbide ceramic, due to its high hardness and stable chemical structure, possesses advantages such as good wear resistance and corrosion resistance. Traditional silicon nitride-bonded silicon carbide is produced by the reaction of metallic silicon in a nitrogen atmosphere. The green body typically requires a certain porosity (15%-20%) to ensure complete nitriding. However, a high porosity of 15-20% limits the mechanical properties of silicon nitride-bonded silicon carbide, with a flexural strength generally between (40-50) ± 5 MPa, and it easily leads to corrosive liquids penetrating to the metal-ceramic interface outside the ceramic component. As a flow-through rotating component, excellent mechanical properties and corrosion resistance are required. Therefore, it is imperative to reduce the porosity of ceramic parts and enhance their mechanical and corrosion resistance. Summary of the Invention

[0003] The purpose of this invention is to solve the problems of high porosity, poor mechanical properties and corrosion resistance of existing pump ceramic materials. To this end, this invention provides a silicon nitride-bonded silicon carbide sintered ceramic material for pumps and its preparation method.

[0004] The objective of this invention is achieved through the following technical solution:

[0005] The present invention discloses a silicon nitride-bonded silicon carbide sintered ceramic material for pumps. The sintered ceramic material, based on a total weight of 120 parts, comprises the following raw materials in parts by weight: 55-70 parts silicon carbide particles; 10-15 parts silicon powder; 5-15 parts silicon-iron-chromium alloy powder; 5-10 parts water-soluble phenolic resin powder; 5-10 parts purified water; 0.5-3 parts defoamer; 3-5 parts sintering aid; and 3-5 parts dispersant.

[0006] The silicon carbide particles have a particle size greater than 75 μm; the particle size distribution of the silicon carbide particles is 5-3 mm, 3-2 mm, and 2-1 mm, and the mass ratio of the three types of silicon carbide particles is (1-14):(1-5):1, and the particle density is greater than 98%.

[0007] The silicon powder has a purity of ≥98% and a particle size of 5-74μm.

[0008] The particle size of the ferrosilicon-chromium alloy powder is 20-240μm, and the purity is ≥99.8%. The mass ratio of silicon, iron and chromium in the ferrosilicon-chromium alloy powder is (7-8):(2-3):(1-2).

[0009] The water-soluble phenolic resin powder is selected from one or a mixture of several grades RS-710, RS-619, RS-518, and RS-122.

[0010] The defoamer is one or a mixture of diethylhexanol, isooctanol, isoamyl alcohol, and diisobutylmethanol.

[0011] The sintering aid is a compound of activated yttrium oxide micro powder, activated lanthanum oxide micro powder and activated alumina micro powder in a mass ratio of (9-14):(1-4):(3-6); the particle size of each component of the sintering aid is 1-74 μm.

[0012] The dispersant is a mixture of 7-9 parts by weight of polyvinylpyrrolidone K90 and 2-3 parts by weight of polyvinylpyrrolidone K30.

[0013] The present invention discloses a method for preparing a silicon nitride-bonded silicon carbide sintered ceramic material for pumps, comprising the following steps:

[0014] S1. Mix silicon powder, ferrosilicon-chromium alloy powder, water-soluble phenolic resin powder, purified water, defoamer, sintering aid and dispersant according to the above formula ratio, and ball mill at 80-120 r / min for 1-48 h; then add silicon carbide particles according to the formula ratio, and roller mill at 10-50 r / min for 2-12 h to mix the raw materials evenly.

[0015] S2. Fill the molding cavity of the mold with the mixed slurry obtained in S1, let it stand for 0.5-2 hours, then add more mixed slurry to fill the molding cavity of the mold again, and then cure at room temperature for 1-2 days to obtain the cured ceramic green body.

[0016] S3. The ceramic green body obtained in S2 is heated to 50-180℃ at a heating rate of 3-10℃ / min, and then dried for 1-7 days before demolding to obtain the dried ceramic green body.

[0017] S4. The ceramic green body obtained in S3 is heated to 1350-1450℃ in a nitrogen atmosphere at a heating rate of 3-10℃ / min and held for 2-8 hours. Then it is cooled to 800℃ at a cooling rate of 3-10℃ / min and then cooled to room temperature in the furnace to obtain sintered ceramic parts.

[0018] S5. The sintered ceramic part obtained in S4 is completely immersed in the wetting liquid under a vacuum of 0.1-1 kPa for 10 min-1 h. Then the wetting ceramic part is dried at 80℃-150℃ for 4-10 h. The above wetting and drying operations are repeated 2-3 times to obtain the target product.

[0019] The impregnation liquid is composed of epoxy resin, curing agent, nano silica and defoamer mixed in a mass ratio of (8-12):(1-4):(0.2-3):(0.1-0.3).

[0020] The epoxy resin is selected from one or more of the grades E-20, E-41, E-44, and E-51, the curing agent is selected from one or more of the grades T31, T520, T31X, T31S, and T33, and the defoamer is selected from one or more of the grades diethylhexanol, isooctanol, isoamyl alcohol, and diisobutylmethanol.

[0021] Beneficial effects

[0022] In the sintered ceramic material of this invention, the content of water-soluble phenolic resin powder and purified water is reduced, resulting in a decrease in the porosity of the sintered ceramic parts to 6%-12%, thus improving the mechanical properties of the ceramics. During nitrogen sintering, the surface layer (5-15mm) of the ceramic parts is fully nitrided, generating high-hardness metal nitrides such as iron nitride, chromium nitride, silicon nitride, and silicon iron nitride, significantly increasing the surface hardness of the ceramic parts and thereby improving their wear resistance. Meanwhile, due to the reduced porosity, the interior of the ceramic parts does not fully react with nitrogen, resulting in certain residual metal phases. A small amount is oxidized to iron oxide, chromium oxide, etc., which promotes sintering. Most of the residual metal phases (iron, chromium, and silicon) exist in the ceramic matrix, thereby improving the mechanical properties and increasing the toughness of the ceramic parts, forming a ceramic / metal composite material with internal toughness and external hardness. Under a nitrogen atmosphere, metal / silicon powder undergoes a nitriding reaction at porous areas, forming corrosion-resistant nitrides such as chromium nitride and silicon nitride. These metal nitrides encapsulate the internal metallic plastic phase of the ceramic part, forming a corrosion-resistant protective layer that significantly improves the ceramic part's corrosion resistance. The sintered ceramic part is then impregnated with resin to further seal any remaining pores, resulting in a denser ceramic surface that further prevents the penetration of corrosive slurries. This ensures both enhanced surface corrosion resistance and prevents corrosive liquids from entering and corroding the internal metal alloys, while also improving the ceramic part's toughness. Adding nano-silica to the impregnation resin, with its numerous silanol groups on the surface, allows it to form a three-dimensional network structure through direct or indirect hydrogen bonding with liquid molecules. Under shear force, this three-dimensional network structure is disrupted first, thus increasing the ceramic part's toughness. Simultaneously, the addition of nanoparticles increases the resin's strength and improves its wear resistance. Detailed Implementation

[0023] The present invention will be further described below with reference to the embodiments.

[0024] Example 1

[0025] A method for preparing a silicon nitride-bonded silicon carbide sintered ceramic material for pumps includes the following steps:

[0026] S1. Ingredients: The weight parts of each raw material in the 10kg composite ceramic material slurry are as follows: 4200g of silicon carbide particles with a particle size of 5-3mm, 1200g of silicon carbide particles with a particle size of 3-2mm, 600g of silicon carbide particles with a particle size of 2-1mm; 1000g of silicon powder; 1120g of ferrosilicon-chromium alloy powder; 750g of water-soluble phenolic resin powder of grade RS-710; 450g of purified water; 30g of defoamer (diethylhexanol); 175g of sintering aid (175g of activated alumina micro powder; 70g of activated yttrium oxide micro powder; 105g of activated lanthanum oxide micro powder); and 225g of dispersant (225g of polyvinylpyrrolidone K90; 75g of polyvinylpyrrolidone K30).

[0027] S2. Raw material mixing: The silicon powder, ferrosilicon-chromium alloy powder, water-soluble phenolic resin powder, purified water, defoamer, sintering aid and dispersant in the above proportions are ball-milled at a speed of 100 r / min for 12 h; then silicon carbide particles (particle size > 75 μm) are added and treated by roller milling at a speed of 25 r / min for 6 h to mix the raw materials evenly.

[0028] S3. Injection molding: Inject the above mixed slurry into the plaster mold, let it stand for 0.5 hours, and after the mold is fully filled with slurry, replenish the fallen liquid level and let it cure at room temperature for 2 days.

[0029] S4. Heating and molding: Place the molded ceramic parts in an oven and gradually heat them to 120℃. Dry them for 3 days, then demold them to obtain the solidified ceramic blank.

[0030] S5. Nitrogen sintering: The ceramic blank is placed in a nitriding furnace, and high-purity nitrogen (nitrogen purity > 99.99%) is introduced. The heating rate is 4℃ per minute, the holding temperature is 1350℃, and the holding time is 5 hours. After the heat treatment is completed, the nitriding furnace is cooled at a rate of 8℃ per minute until it reaches 800℃. Then, the furnace is cooled to room temperature to obtain the sintered ceramic part.

[0031] S6. Resin Impregnation: Place the ceramic in a vacuum chamber with a cylinder, evacuate to 0.1 kPa, and inject impregnation liquid into the cylinder until the ceramic is completely submerged. The impregnation liquid consists of E-41 epoxy resin, T31 curing agent, nano silica, and defoamer (diethylhexanol) in a mass ratio of 7:2:1.6:0.4. Prepare 5 kg of impregnation liquid, immerse for 0.5 h, remove the ceramic part, dry at 80℃ for 4 h, and repeat the vacuum impregnation twice.

[0032] Example 2

[0033] A method for preparing a silicon nitride-bonded silicon carbide sintered ceramic material for pumps includes the following steps:

[0034] S1. Ingredients: The weight proportions of each raw material in the 10kg composite ceramic material slurry are as follows: 4200g of silicon carbide particles with a particle size of 5-3mm, 1200g of silicon carbide particles with a particle size of 3-2mm, 600g of silicon carbide particles with a particle size of 2-1mm; 1000g of silicon powder; 1020g of ferrosilicon-chromium alloy powder; 800g of water-soluble phenolic resin powder of grade RS-619; 500g of purified water; 30g of defoamer (isooctanol); 175g of sintering aid (175g of activated alumina micro powder; 70g of activated yttrium oxide micro powder; 105g of activated lanthanum oxide micro powder); and 225g of dispersant (225g of polyvinylpyrrolidone K90; 75g of polyvinylpyrrolidone K30).

[0035] S2. Raw material mixing: The silicon powder, ferrosilicon-chromium alloy powder, water-soluble phenolic resin powder, purified water, defoamer, sintering aid and dispersant in the above proportions are ball-milled at a speed of 100 r / min for 12 h; then silicon carbide particles (particle size > 75 μm) are added and treated by roller milling at a speed of 25 r / min for 6 h to mix the raw materials evenly.

[0036] S3. Injection molding: Inject the above mixed slurry into the plaster mold, let it stand for 0.5 hours, and after the mold is fully filled with slurry, replenish the fallen liquid level and let it cure at room temperature for 2 days.

[0037] S4. Heating and molding: Place the molded ceramic parts in an oven and gradually heat them to 120℃. Dry them for 3 days, then demold them to obtain the solidified ceramic blank.

[0038] S5. Nitrogen sintering: The ceramic blank is placed in a nitriding furnace, and high-purity nitrogen (nitrogen purity > 99.99%) is introduced. The heating rate is 4℃ per minute, the holding temperature is 1350℃, and the holding time is 5 hours. After the heat treatment is completed, the nitriding furnace is cooled at a rate of 8℃ per minute until it reaches 800℃. Then, the furnace is cooled to room temperature to obtain the sintered ceramic part.

[0039] S6. Resin Impregnation: Place the ceramic in a vacuum chamber with a cylinder, evacuate to 0.1 kPa, and inject impregnation liquid into the cylinder until the ceramic is completely submerged. The impregnation liquid consists of E-44 epoxy resin, T520 curing agent, nano silica, and defoamer (isooctanol) in a mass ratio of 7:2:1.6:0.4. Prepare 5 kg of impregnation liquid, immerse for 0.7 h, remove the ceramic part, dry at 100℃ for 3 h, and repeat the vacuum impregnation twice.

[0040] Example 3

[0041] A method for preparing a silicon nitride-bonded silicon carbide sintered ceramic material for pumps includes the following steps:

[0042] S1. Ingredients: The weight proportions of each raw material in the 10kg composite ceramic material slurry are as follows: 4200g of silicon carbide particles with a particle size of 5-3mm, 1200g of silicon carbide particles with a particle size of 3-2mm, 600g of silicon carbide particles with a particle size of 2-1mm; 1000g of silicon powder; 920g of ferrosilicon-chromium alloy powder; 850g of water-soluble phenolic resin powder of grade RS-518; 500g of purified water; 30g of defoamer (isoamyl alcohol); 175g of sintering aid (175g of activated alumina micro powder; 70g of activated yttrium oxide micro powder; 105g of activated lanthanum oxide micro powder); and 225g of dispersant (225g of polyvinylpyrrolidone K90; 75g of polyvinylpyrrolidone K30).

[0043] S2. Raw material mixing: The silicon powder, ferrosilicon-chromium alloy powder, water-soluble phenolic resin powder, purified water, defoamer, sintering aid and dispersant in the above proportions are ball-milled at a speed of 100 r / min for 12 h; then silicon carbide particles (particle size > 75 μm) are added and treated by roller milling at a speed of 25 r / min for 6 h to mix the raw materials evenly.

[0044] S3. Injection molding: Inject the above mixed slurry into the plaster mold, let it stand for 0.5 hours, and after the mold is fully filled with slurry, replenish the fallen liquid level and let it cure at room temperature for 2 days.

[0045] S4. Heating and molding: Place the molded ceramic parts in an oven and gradually heat them to 120℃. Dry them for 3 days, then demold them to obtain the solidified ceramic blank.

[0046] S5. Nitrogen sintering: The ceramic blank is placed in a nitriding furnace, and high-purity nitrogen (nitrogen purity > 99.99%) is introduced. The heating rate is 4℃ per minute, the holding temperature is 1350℃, and the holding time is 5 hours. After the heat treatment is completed, the nitriding furnace is cooled at a rate of 8℃ per minute until it reaches 800℃. Then, the furnace is cooled to room temperature to obtain the sintered ceramic part.

[0047] S6. Resin Impregnation: Place the ceramic in a vacuum chamber with a cylinder, evacuate to 0.1 kPa, and inject impregnation liquid into the cylinder until the ceramic is completely submerged. The impregnation liquid consists of E-51 epoxy resin, T31X curing agent, nano silica, and defoamer (isoamyl alcohol) in a mass ratio of 7:2:1.6:0.4. Prepare 5 kg of impregnation liquid, immerse for 0.5 h, remove the ceramic part, dry at 70℃ for 6 h, and repeat the vacuum impregnation process twice.

[0048] Example 4

[0049] A method for preparing a silicon nitride-bonded silicon carbide sintered ceramic material for pumps includes the following steps:

[0050] S1. Ingredients: The weight parts of each raw material in the 10kg composite ceramic material slurry are as follows: 4200g of silicon carbide particles with a particle size of 5-3mm, 1200g of silicon carbide particles with a particle size of 3-2mm, 600g of silicon carbide particles with a particle size of 2-1mm; 1000g of silicon powder; 1120g of ferrosilicon-chromium alloy powder; 750g of water-soluble phenolic resin powder of grade RS-122; 450g of purified water; 30g of defoamer (diisobutylmethanol); 175g of sintering aid (175g of activated alumina micro powder; 70g of activated yttrium oxide micro powder; 105g of activated lanthanum oxide micro powder); and 225g of dispersant (225g of polyvinylpyrrolidone K90; 75g of polyvinylpyrrolidone K30).

[0051] S2. Raw material mixing: The silicon powder, ferrosilicon-chromium alloy powder, water-soluble phenolic resin powder, purified water, defoamer, sintering aid and dispersant in the above proportions are ball-milled at a speed of 100 r / min for 12 h; then silicon carbide particles (particle size > 75 μm) are added and treated by roller milling at a speed of 25 r / min for 6 h to mix the raw materials evenly.

[0052] S3. Injection molding: Inject the above mixed slurry into the plaster mold, let it stand for 0.5 hours, and after the mold is fully filled with slurry, replenish the fallen liquid level and let it cure at room temperature for 2 days.

[0053] S4. Heating and molding: Place the molded ceramic parts in an oven and gradually heat them to 120℃. Dry them for 3 days, then demold them to obtain the solidified ceramic blank.

[0054] S5. Nitrogen sintering: The ceramic blank is placed in a nitriding furnace, and high-purity nitrogen (nitrogen purity > 99.99%) is introduced. The heating rate is 4℃ per minute, the holding temperature is 1350℃, and the holding time is 5 hours. After the heat treatment is completed, the nitriding furnace is cooled at a rate of 8℃ per minute until it reaches 800℃. Then, the furnace is cooled to room temperature to obtain the sintered ceramic part.

[0055] S6. Resin Impregnation: Place the ceramic in a vacuum chamber with a cylinder, evacuate to 0.1 kPa, and inject impregnation liquid into the cylinder until the ceramic is completely submerged. The impregnation liquid consists of a mixture of epoxy resins of grades E-44 and E-51, a curing agent of grade T31S, nano-silica, and a defoamer (diisobutylmethanol) in a mass ratio of 4:3:2:1.6:0.4. Prepare 5 kg of impregnation liquid, immerse for 1 hour, remove the ceramic part, dry at 60℃ for 7 hours, and repeat the vacuum impregnation process 3 times.

[0056] The ceramic samples obtained in Examples 1-4 were tested for performance using the following standards:

[0057] 1. The bulk density and apparent porosity of the sample were tested using an apparent porosity tester (model: XKQ-01) (GB / T2997-2015 standard);

[0058] 2. The room temperature flexural strength of the specimens was tested using a microcomputer-controlled fully automatic flexural strength testing machine (main unit model: CCS600 / 20P). Three specimens were tested for each group of specimens (GB / T3001-2017 standard).

[0059] 3. The bottom and surface of the sample were eroded once each using a sand-containing slurry to test the sample's abrasion resistance at room temperature. The sand-containing slurry was a mixture of 80-mesh mullite, 80-mesh quartz sand, and water (mass ratio 1:1:8). The erosion angle was 30°, the erosion time was 30 minutes, and the erosion pressure was 0.3 MPa. The abrasion resistance of the sample was measured by the sample loss volume, calculated using the following formula:

[0060]

[0061] Where: V s V1 represents the volume lost due to erosion; m1 represents the mass before erosion; m2 represents the mass after erosion; and V1 represents the volume before erosion.

[0062] The specific test performance results are as follows:

[0063] Example 1: After sintering with added alloy powder, the porosity was 8.2%; the flexural strength at room temperature was 65.5 MPa; and the abrasion resistance at room temperature was 0.135 cm. 2 The resin-impregnated porosity is 1.1%; the room temperature flexural strength is 70.7 MPa; and the room temperature abrasion resistance is 0.106 cm. 2 .

[0064] Example 2: After sintering with added alloy powder, the porosity was 8.9%; the flexural strength at room temperature was 60.4 MPa; and the abrasion resistance at room temperature was 0.163 cm. 2 The resin-impregnated porosity is 1.4%; the room temperature flexural strength is 67.6 MPa; and the room temperature abrasion resistance is 0.149 cm.2 .

[0065] Example 3: After sintering with added alloy powder, the porosity was 10.0%; the flexural strength at room temperature was 55.1 MPa; and the abrasion resistance at room temperature was 0.184 cm. 2 The resin-impregnated porosity is 1.8%; the room temperature flexural strength is 62.0 MPa; and the room temperature abrasion resistance is 0.153 cm. 2 .

[0066] Example 4: After sintering with added alloy powder, the porosity was 8.1%; the flexural strength at room temperature was 65.5 MPa; and the abrasion resistance at room temperature was 0.136 cm. 2 The resin-impregnated porosity is 0.9%; the room temperature flexural strength is 70.8 MPa; and the room temperature abrasion resistance is 0.109 cm. 2 .

[0067] As shown in Examples 1, 2, 3, and 4, by reducing the use of purified water and water-soluble phenolic resin powder and increasing the content of ferrosilicon-chromium alloy powder while ensuring workability and green body strength, the porosity after sintering decreases, and the room temperature flexural strength and abrasion resistance are improved. After filling the pores with a wetting agent, the porosity further decreases, and the room temperature flexural strength and abrasion resistance are also improved.

Claims

1. A silicon nitride-bonded silicon carbide sintered ceramic material for pumps, characterized in that: The sintered ceramic material, based on a total weight of 120 parts, comprises the following raw materials in the following weight proportions: 55-70 parts silicon carbide particles; 10-15 parts silicon powder; 5-15 parts ferrosilicon-chromium alloy powder; 5-10 parts water-soluble phenolic resin powder; 5-10 parts purified water; 0.5-3 parts defoamer; 3-5 parts sintering aid; and 3-5 parts dispersant. The defoamer is one or a mixture of diethylhexanol, isooctanol, isoamyl alcohol, and diisobutylmethanol. The sintering aid is a compound of activated yttrium oxide micro powder, activated lanthanum oxide micro powder and activated alumina micro powder in a mass ratio of (9-14):(1-4):(3-6); The dispersant is a mixture of 7-9 parts by weight of polyvinylpyrrolidone K90 and 2-3 parts by weight of polyvinylpyrrolidone K30; A method for preparing a silicon nitride-bonded silicon carbide sintered ceramic material for pumps includes the following steps: S1. Mix silicon powder, ferrosilicon-chromium alloy powder, water-soluble phenolic resin powder, purified water, defoamer, sintering aid and dispersant according to the above formula ratio, and ball mill at 80-120 r / min for 1-48 h; then add silicon carbide particles according to the formula ratio, and roller mill at 10-50 r / min for 2-12 h to mix the raw materials evenly. S2. Fill the molding cavity of the mold with the mixed slurry obtained in S1, let it stand for 0.5-2 hours, then add more mixed slurry to fill the molding cavity of the mold again, and then cure at room temperature for 1-2 days to obtain the cured ceramic green body. S3. The ceramic green body obtained in S2 is heated to 50-180℃ at a heating rate of 3-10℃ / min, and then dried for 1-7 days before demolding to obtain the dried ceramic green body. S4. The ceramic green body obtained in S3 is heated to 1350-1450℃ in a nitrogen atmosphere at a heating rate of 3-10℃ / min and held for 2-8 hours. Then it is cooled to 800℃ at a cooling rate of 3-10℃ / min and then cooled to room temperature in the furnace to obtain sintered ceramic parts. S5. The sintered ceramic parts obtained in S4 are completely immersed in the wetting liquid under a vacuum of 0.1-1 kPa for 10 min-1 h. Then the wetting ceramic parts are dried at 80℃-150℃ for 4-10 h. The above wetting and drying operations are repeated 2-3 times to obtain the target product. The impregnation liquid is composed of epoxy resin, curing agent, nano silica and defoamer mixed in a mass ratio of (8-12):(1-4):(0.2-3):(0.1-0.3).

2. The silicon nitride-bonded silicon carbide sintered ceramic material for pumps as described in claim 1, characterized in that: The silicon carbide particles have a particle size greater than 75 μm; the particle size distribution of the silicon carbide particles is 5-3 mm, 3-2 mm, and 2-1 mm, and the mass ratio of the three types of silicon carbide particles is (1-14):(1-5):1, and the particle density is greater than 98%.

3. The silicon nitride-bonded silicon carbide sintered ceramic material for pumps as described in claim 1, characterized in that: The silicon powder has a purity of ≥98% and a particle size of 5-74μm.

4. The silicon nitride-bonded silicon carbide sintered ceramic material for pumps as described in claim 1, characterized in that: The particle size of the ferrosilicon-chromium alloy powder is 20-240 μm, and the purity is ≥99.8%. The mass ratio of silicon, iron and chromium in the ferrosilicon-chromium alloy powder is (7-8):(2-3):(1-2).

5. The silicon nitride-bonded silicon carbide sintered ceramic material for pumps as described in claim 1, characterized in that: The water-soluble phenolic resin powder is selected from one or a mixture of several grades RS-710, RS-619, RS-518, and RS-122.

6. The silicon nitride-bonded silicon carbide sintered ceramic material for pumps as described in claim 1, characterized in that: The particle size of each component of the sintering aid is 1-74 μm.

7. The method for preparing a silicon nitride-bonded silicon carbide sintered ceramic material for pumps as described in claim 1, characterized in that: The epoxy resin in the impregnation liquid is selected from one or more of the grades E-20, E-41, E-44, and E-51, and the curing agent in the impregnation liquid is selected from one or more of the grades T31, T520, T31X, T31S, and T33, and the defoamer in the impregnation liquid is selected from one or more of the grades diethylhexanol, isooctanol, isoamyl alcohol, and diisobutylmethanol.

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