Hard alloy bearing for hard rock deep drilling and preparation method thereof

Abstract

The invention relates to the technical field of hard alloy materials, and discloses a hard alloy bearing for hard rock deep drilling and a preparation method thereof.The preparation method comprises the following preparation steps that tungsten carbide powder, aluminum powder, cobalt powder, nickel powder, iron powder, graphite powder and reinforcing filler are mixed and subjected to ball milling, and a mixture is obtained; the mixture is placed in a bearing mold to be pressed into a prefabricated blank; and the prefabricated blank is placed in a sintering furnace to be sintered and cooled to the room temperature, and the hard alloy bearing is obtained through aftertreatment, grinding and polishing. The reinforcing filler can be adsorbed to the surface of the alloy powder, so that the alloy powder is adhered to form a compact structure, and the reinforcing filler can improve the heat resistance of the hard alloy bearing, absorb and weaken stress generated by external force and enhance the compressive strength of the alloy bearing, and in addition, the reinforcing filler can supplement the carbon content in the alloy. And the situation that in the preparation process of the alloy bearing, extra carbon loss is caused due to the high oxygen content, and the mechanical performance of the alloy bearing is affected is avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of cemented carbide materials, in particular to a cemented carbide bearing for hard rock deep drilling and a preparation method thereof. Background Art

[0002] Cemented carbide is a type of cemented carbide bearing produced by powder metallurgy, which uses refractory metal carbide (tungsten carbide) as the hard phase and transition metal elements (cobalt, nickel, iron, etc.) as the bonding phase. It has excellent wear resistance, compressive strength, hardness, labor strength and load-bearing capacity, as well as good plasticity and impact toughness. As a bearing material, it is widely used in the field of deep hard rock drilling.

[0003] During the powder metallurgy process, cemented carbide bearings have the problem of poor structural uniformity. Their hardness, toughness and strength are low, making it difficult for them to withstand the impact strength brought by deep hard rock drilling. As the depth of deep hard rock drilling increases, the formation temperature becomes higher, and the heat is difficult to diffuse in the cemented carbide bearings, causing the cemented carbide bearings to deteriorate and affecting their service life. Summary of the Invention

[0004] The present invention provides a cemented carbide bearing for hard rock deep drilling and a preparation method thereof, which solves the problems of poor structural uniformity of cemented carbide bearings and difficulty in heat diffusion in the cemented carbide bearings, which leads to deterioration of the cemented carbide bearings.

[0005] The technical solution of the present invention: A method for preparing a cemented carbide bearing for deep hard rock drilling comprises the following steps: S1. The tungsten carbide powder, aluminum powder, cobalt powder, nickel powder, iron powder, graphite powder and reinforcing filler are mixed and ball-milled to obtain a mixture; S2. The mixture is placed in a bearing mold and pressed into a preform; S3. The preform is placed in a sintering furnace, sintered, cooled to room temperature, and post-processed, ground, and polished to obtain a cemented carbide bearing; The reinforcing filler is obtained by surface treating the composite material with carboxymethyl cellulose and then mixing and reacting it with sulfonated lignin. The composite material is made by adhering nano-silicon nitride to the surface of silicon carbide nanosheets through tannic acid, then mixing it with glucose, carbonizing it at high temperature, and then intercalating it into the interlayers of graphene oxide. Furthermore, in step S1, the mass ratio of tungsten carbide powder, aluminum powder, cobalt powder, nickel powder, iron powder, graphite powder and reinforcing filler is 100:(5-6):(2-4):(4-6):(6-8):(1-3):(5-6).

[0006] Furthermore, in step S1, the ball mill is used, the ball-to-material ratio is (8-10):1, the rotation speed is 200-300 r / min, and the ball milling time is 15-20 h.

[0007] Furthermore, in step S2, the pressing pressure is 300-350 MPa, and the pressing time is 30-40 s.

[0008] Furthermore, in step S3, the sintering temperature is 1300-1380°C, the sintering time is 2-4h, the sintering pressure is 40-50Pa, and the sintering is carried out in a nitrogen atmosphere with a nitrogen introduction rate of 50-60mL / min.

[0009] Furthermore, the reinforcing filler is specifically prepared by the following steps: A1. Add tannic acid to ethanol and stir until completely dissolved. Add silicon carbide nanosheets and stir. Add nano-silicon nitride and continue stirring. Filter, wash, and dry to obtain nano-silicon nitride-loaded silicon carbide nanosheets. A2. The silicon carbide nanosheets loaded with nano-silicon nitride, glucose, and citric acid were added to ethanol, hydrochloric acid was added, stirred, filtered, washed, dried, potassium hydroxide solution was added, nitrogen was introduced, carbonized, cooled to room temperature, removed, washed, and dried to obtain modified silicon carbide nanosheets; A3. Graphene oxide was added to deionized water, stirred evenly, modified silicon carbide nanosheets were added, and after ultrasonic treatment, the mixture was filtered, washed, and dried to obtain a composite material; A4. Add carboxymethyl cellulose to deionized water and stir evenly. Add the composite material and stir. Add sulfonated lignin and hydrochloric acid. After stirring for reaction, filter, wash, and dry to obtain a reinforcing filler.

[0010] Furthermore, during the above-mentioned reaction A1, tannic acid contains a large number of phenolic hydroxyl groups and has good adhesion properties, so that nano-silicon nitride adheres to the surface of silicon carbide nanosheets through tannic acid, thereby obtaining silicon carbide nanosheets loaded with nano-silicon nitride.

[0011] Furthermore, in the above-mentioned A2 reaction process, citric acid is used as a linker, so that glucose is coated on the surface of the silicon carbide nanosheet loaded with nano-silicon nitride through citric acid. After high-temperature carbonization, the glucose is thermally decomposed to form a dense carbon layer. Potassium hydroxide solution is used as an activator to form pores on the surface of the dense carbon layer, thereby realizing the synthesis of a porous carbon structure on the surface of the silicon carbide nanosheet loaded with nano-silicon nitride, and obtaining a modified silicon carbide nanosheet.

[0012] Furthermore, during the above-mentioned reaction A3, the interlayer gaps of graphene oxide are abundant, and ultrasonic treatment can weaken the bonding force between the graphene oxide layers, so that the modified silicon carbide nanosheets are intercalated between the graphene oxide layers to form a composite material.

[0013] Furthermore, in the above-mentioned A4 reaction process, carboxymethyl cellulose serves as a binder, and the carboxyl groups it contains can bond with the oxygen-containing functional groups on the surface of the composite material through hydrogen bonds, so that the carboxymethyl cellulose is coated on the surface of the composite material; the carboxyl groups contained in the carboxymethyl cellulose can combine with the hydroxyl groups of the sulfonated lignin, so that the sulfonated lignin is cross-linked to form a network structure coated on the surface of the composite material, serving as a reinforcing filler.

[0014] Furthermore, in step A1, the ratio of tannic acid, ethanol, silicon carbide nanosheets and nano-silicon nitride is (0.2-0.4) g: (35-45) mL: (1-1.4) g: (0.6-1) g.

[0015] Furthermore, in step A2, the amount ratio of the nano-silicon nitride-loaded silicon carbide nanosheets, glucose, citric acid, ethanol, hydrochloric acid and potassium hydroxide solution is (1-2) g: (2-3) g: (0.4-0.6) g: (90-110) mL: (1-2) mL: (4-6) mL.

[0016] Furthermore, in step A3, the ratio of graphene oxide, deionized water, and modified silicon carbide nanosheets is (1-2) g: (80-120) mL: (1-1.4) g.

[0017] Furthermore, in step A4, the ratio of carboxymethyl cellulose, deionized water, composite material, sulfonated lignin and hydrochloric acid is (0.6-1) g: (75-85) mL: (1.4-1.8) g: (1.5-2.5) g: (1-3) mL.

[0018] The present invention has the following beneficial effects: (1) In the technical solution of the present invention, nano-silicon nitride is adhered to the surface of silicon carbide nanosheets through tannic acid. On the one hand, nano-silicon nitride has a high thermal conductivity and can improve the heat dissipation rate of cemented carbide bearings, thereby avoiding the problem that as the depth of deep drilling in hard rock increases, the formation temperature becomes high and the heat is difficult to diffuse in the cemented carbide bearings, resulting in deterioration of the cemented carbide bearings and affecting the service life of the cemented carbide bearings. On the other hand, silicon carbide nanosheets, as a carrier of nano-silicon nitride, can improve the dispersibility of nano-silicon nitride in the alloy and improve the structural uniformity of the alloy.

[0019] (2) In the technical solution of the present invention, a porous carbon structure is synthesized on the surface of silicon carbide nanosheets loaded with nano-silicon nitride. On the one hand, the synthesized porous carbon has high adsorption performance and can adsorb and fix nano-silicon nitride, thereby preventing the nano-silicon nitride from falling off when the cemented carbide bearing is used under high wear resistance and high pressure, causing cracks in the alloy bearing. The high specific surface area and pore structure of the porous carbon can enhance the heat conduction path of the cemented carbide bearing and improve the heat dissipation performance. On the other hand, the nano-silicon nitride adsorbed into the pores of the porous carbon serves as the supporting skeleton of the porous carbon, avoiding the collapse of the cavities of the porous carbon. In addition, during the sintering process, the carbon element contained in the porous carbon can form a metal carbide reinforcement phase with the molten metal powder, filling the gaps in the alloy bearing, thereby improving the density of the alloy bearing and enhancing the mechanical strength of the alloy bearing.

[0020] (3) In the technical solution of the present invention, modified silicon carbide nanosheets are intercalated between graphene oxide layers. On the one hand, the nano silicon nitride and porous carbon between the layers of the formed layered composite material serve as heat conduction channels, further enhancing the heat conduction path of the cemented carbide bearing and improving the heat dissipation performance. In addition, the formed layered composite material can absorb and reduce the stress generated by external forces, thereby enhancing the compressive strength of the alloy bearing. On the other hand, the alloy powder melt can be adsorbed between the layers of the layered composite material, so that the composite filler is evenly dispersed in the alloy, thereby improving the density of the alloy bearing.

[0021] (4) In the technical solution of the present invention, carboxymethyl cellulose is coated on the surface of the layered composite material and then reacts with sulfonated lignin to form a cross-linked network structure coated on the surface of the layered composite material. On the one hand, sulfonated lignin and carboxymethyl cellulose contain a large number of hydroxyl groups, which can be adsorbed on the surface of the alloy powder to improve the density of the alloy powder. On the other hand, during the sintering process, the lignin-based cross-linked network structure is carbonized to form a dense cross-linked carbon network structure, which can supplement the carbon content in the alloy and avoid additional carbon loss during the preparation of the alloy bearing due to the high oxygen content, thereby affecting the mechanical properties of the alloy bearing. DETAILED DESCRIPTION

[0022] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0023] The raw materials used in the examples of the present invention are as follows, and all reagents used are of analytical grade.

[0024] The average particle size of tungsten carbide powder, aluminum powder, cobalt powder, nickel powder, iron powder and graphite powder is 2.5um.

[0025] The diameter of the silicon carbide nanosheets is 10μm, the brand is Dekedaojin, Beijing Dekedaojin Technology Co., Ltd.

[0026] Nano-silicon nitride particles with a particle size of 20 nm were purchased from Hubei Langbowan Biopharmaceutical Co., Ltd.

[0027] The graphene oxide sheet had a diameter of 10 μm and was purchased from Hangzhou Zheming New Materials Co., Ltd.

[0028] Example 1 A method for preparing a cemented carbide bearing for hard rock deep drilling comprises the following steps: S1. The tungsten carbide powder, aluminum powder, cobalt powder, nickel powder, iron powder, graphite powder and reinforcing filler are mixed and ball-milled to obtain a mixture; S2. The mixture is placed in a bearing mold and pressed into a preform; S3. Place the prefabricated body in a sintering furnace for sintering, cool to room temperature, and then post-process, grind, and polish to obtain a cemented carbide bearing.

[0029] Wherein, in step S1, the mass ratio of tungsten carbide powder, aluminum powder, cobalt powder, nickel powder, iron powder, graphite powder and reinforcing filler is 100:5:2:4:6:1:5; In step S1, the ball mill is used, the ball-to-material ratio is 8:1, the rotation speed is 200 r / min, and the ball milling time is 15 h; In step S2, the pressing pressure is 300 MPa and the pressing time is 30 s; In step S3, the sintering temperature is 1300° C., the sintering time is 2 h, the sintering pressure is 40 Pa, and the sintering is carried out in a nitrogen atmosphere with a nitrogen introduction rate of 50 mL / min.

[0030] The reinforcing filler is specifically prepared by the following steps: A1. Add 0.2 g of tannic acid to 35 mL of ethanol and stir until completely dissolved. Then add 1 g of silicon carbide nanosheets and stir at 70°C for 40 minutes. Then add 0.6 g of nano-silicon nitride and continue stirring for 40 minutes. The mixture is filtered, washed three times with deionized water, and dried in a 70°C oven for 10 minutes to obtain silicon carbide nanosheets loaded with nano-silicon nitride. A2. 1 g of silicon nitride nanosheets loaded with silicon carbide nanosheets, 2 g of glucose, and 0.4 g of citric acid were added to 90 mL of ethanol. 1 mL of 36% hydrochloric acid was added and stirred at 70°C for 30 min. The mixture was filtered, washed three times with deionized water, and dried in a 70°C oven for 10 min. The mixture was then placed in a tube furnace, and 4 mL of 30% potassium hydroxide solution was added. Nitrogen was introduced and carbonized at 800°C for 4 h. The mixture was cooled to room temperature, removed, washed three times with deionized water, and dried in a 70°C oven for 10 min to obtain modified silicon carbide nanosheets. A3. 1 g of graphene oxide was added to 80 mL of deionized water and stirred. 1 g of modified silicon carbide nanosheets was added and ultrasonicated at 40 kHz for 20 min. The mixture was filtered, washed three times with deionized water, and dried in an oven at 80°C for 10 min to obtain a composite material. A4. Add 0.6 g of carboxymethyl cellulose to 75 mL of deionized water and stir well. Then add 1.4 g of the composite material and stir for 30 minutes. Then add 1.5 g of sulfonated lignin and 1 mL of 36% hydrochloric acid. Stir and react at 60°C for 20 minutes. Filter, wash three times with deionized water, and dry in an oven at 70°C for 10 minutes to obtain the reinforcing filler.

[0031] Example 2 A method for preparing a cemented carbide bearing for hard rock deep drilling comprises the following steps: S1. The tungsten carbide powder, aluminum powder, cobalt powder, nickel powder, iron powder, graphite powder and reinforcing filler are mixed and ball-milled to obtain a mixture; S2. The mixture is placed in a bearing mold and pressed into a preform; S3. Place the prefabricated body in a sintering furnace for sintering, cool to room temperature, and then post-process, grind, and polish to obtain a cemented carbide bearing.

[0032] Wherein, in step S1, the mass ratio of tungsten carbide powder, aluminum powder, cobalt powder, nickel powder, iron powder, graphite powder and reinforcing filler is 100:5.5:3:5:7:2:5.5; In step S1, the ball mill is used, the ball-to-material ratio is 9:1, the rotation speed is 250 r / min, and the ball milling time is 18 h; In step S2, the pressing pressure is 330 MPa and the pressing time is 35 s; In step S3, the sintering temperature is 1340° C., the sintering time is 3 h, the sintering pressure is 45 Pa, and the sintering is carried out in a nitrogen atmosphere with a nitrogen introduction rate of 55 mL / min.

[0033] The reinforcing filler is specifically prepared by the following steps: A1. Add 0.3 g of tannic acid to 40 mL of ethanol and stir until completely dissolved. Then add 1.2 g of silicon carbide nanosheets and stir at 70°C for 40 minutes. Then add 0.8 g of nano-silicon nitride and continue stirring for 40 minutes. The mixture is filtered, washed three times with deionized water, and dried in a 70°C oven for 10 minutes to obtain silicon carbide nanosheets loaded with nano-silicon nitride. A2. 1.5 g of nano-silicon nitride-loaded silicon carbide nanosheets, 2.5 g of glucose, and 0.5 g of citric acid were added to 100 mL of ethanol. 1.5 mL of 36% hydrochloric acid was added and stirred at 70°C for 30 min. The mixture was filtered, washed three times with deionized water, and dried in a 70°C oven for 10 min. The mixture was then placed in a tube furnace, and 5 mL of 30% potassium hydroxide solution was added. Nitrogen was introduced and carbonized at 800°C for 4 h. The mixture was cooled to room temperature, removed, washed three times with deionized water, and dried in a 70°C oven for 10 min to obtain modified silicon carbide nanosheets. A3. 1.5 g of graphene oxide was added to 100 mL of deionized water and stirred. 1.2 g of modified silicon carbide nanosheets was added and ultrasonicated at 40 kHz for 20 min. The mixture was filtered, washed three times with deionized water, and dried in an oven at 80 ° C for 10 min to obtain a composite material. A4. Add 0.8 g of carboxymethyl cellulose to 80 mL of deionized water and stir well. Then add 1.6 g of the composite material and stir for 30 minutes. Then add 2 g of sulfonated lignin and 2 mL of 36% hydrochloric acid. Stir and react at 60°C for 20 minutes. Filter, wash three times with deionized water, and dry in an oven at 70°C for 10 minutes to obtain the reinforcing filler.

[0034] Example 3 A method for preparing a cemented carbide bearing for hard rock deep drilling comprises the following steps: S1. The tungsten carbide powder, aluminum powder, cobalt powder, nickel powder, iron powder, graphite powder and reinforcing filler are mixed and ball-milled to obtain a mixture; S2. The mixture is placed in a bearing mold and pressed into a preform; S3. Place the prefabricated body in a sintering furnace for sintering, cool to room temperature, and then post-process, grind, and polish to obtain a cemented carbide bearing.

[0035] Wherein, in step S1, the mass ratio of tungsten carbide powder, aluminum powder, cobalt powder, nickel powder, iron powder, graphite powder and reinforcing filler is 100:6:4:6:8:3:6; In step S1, the ball mill is used, the ball-to-material ratio is 10:1, the rotation speed is 300 r / min, and the ball milling time is 20 h; In step S2, the pressing pressure is 350 MPa and the pressing time is 40 s; In step S3, the sintering temperature is 380° C., the sintering time is 4 h, the sintering pressure is 50 Pa, and the sintering is carried out in a nitrogen atmosphere with a nitrogen introduction rate of 60 mL / min.

[0036] The reinforcing filler is specifically prepared by the following steps: A1. Add 0.4 g of tannic acid to 45 mL of ethanol and stir until completely dissolved. Then add 1.4 g of silicon carbide nanosheets and stir at 70°C for 40 minutes. Then add 1 g of nano-silicon nitride and continue stirring for 40 minutes. The mixture is filtered, washed three times with deionized water, and dried in a 70°C oven for 10 minutes to obtain silicon carbide nanosheets loaded with nano-silicon nitride. A2. 2 g of silicon nitride nanosheets loaded with silicon carbide nanosheets, 3 g of glucose, and 0.6 g of citric acid were added to 110 mL of ethanol. 2 mL of 36% hydrochloric acid was added and stirred at 70°C for 30 min. The mixture was filtered, washed three times with deionized water, and dried in a 70°C oven for 10 min. The mixture was then placed in a tube furnace, and 6 mL of 30% potassium hydroxide solution was added. Nitrogen was introduced and carbonized at 800°C for 4 h. The mixture was cooled to room temperature, removed, washed three times with deionized water, and dried in a 70°C oven for 10 min to obtain modified silicon carbide nanosheets. A3. 2 g of graphene oxide was added to 120 mL of deionized water and stirred. 1.4 g of modified silicon carbide nanosheets was added and ultrasonicated at 40 kHz for 20 min. The mixture was filtered, washed three times with deionized water, and dried in an oven at 80 ° C for 10 min to obtain a composite material. A4. Add 1 g of carboxymethyl cellulose to 85 mL of deionized water and stir until well combined. Then, add 1.8 g of the composite material and stir for 30 minutes. Then, add 2.5 g of sulfonated lignin and 3 mL of 36% hydrochloric acid. Stir and react at 60°C for 20 minutes. Filter, wash three times with deionized water, and dry in an oven at 70°C for 10 minutes to obtain the reinforcing filler.

[0037] Comparative Example 1 A method for preparing a cemented carbide bearing for deep hard rock drilling comprises the following steps: S1. The tungsten carbide powder, aluminum powder, cobalt powder, nickel powder, iron powder, graphite powder and reinforcing filler are mixed and ball-milled to obtain a mixture; S2. The mixture is placed in a bearing mold and pressed into a preform; S3. Place the prefabricated body in a sintering furnace for sintering, cool to room temperature, and then post-process, grind, and polish to obtain a cemented carbide bearing.

[0038] Wherein, in step S1, the mass ratio of tungsten carbide powder, aluminum powder, cobalt powder, nickel powder, iron powder, graphite powder and reinforcing filler is 100:6:4:6:8:3:6; In step S1, the ball mill is used, the ball-to-material ratio is 10:1, the rotation speed is 300 r / min, and the ball milling time is 20 h; In step S2, the pressing pressure is 350 MPa and the pressing time is 40 s; In step S3, the sintering temperature is 380° C., the sintering time is 4 h, the sintering pressure is 50 Pa, and the sintering is carried out in a nitrogen atmosphere with a nitrogen introduction rate of 60 mL / min.

[0039] The reinforcing filler is specifically prepared by the following steps: A1. 45 mL of ethanol and 1.4 g of silicon carbide nanosheets were stirred at 70°C for 40 min. 1 g of nano-silicon nitride was added and stirred for another 40 min. The mixture was filtered, washed three times with deionized water, and dried in a 70°C oven for 10 min to obtain nano-silicon nitride-loaded silicon carbide nanosheets. A2. 2 g of silicon nitride nanosheets loaded with silicon carbide nanosheets, 3 g of glucose, and 0.6 g of citric acid were added to 110 mL of ethanol. 2 mL of 36% hydrochloric acid was added and stirred at 70°C for 30 min. The mixture was filtered, washed three times with deionized water, and dried in a 70°C oven for 10 min. The mixture was then placed in a tube furnace, and 6 mL of 30% potassium hydroxide solution was added. Nitrogen was introduced and carbonized at 800°C for 4 h. The mixture was cooled to room temperature, removed, washed three times with deionized water, and dried in a 70°C oven for 10 min to obtain modified silicon carbide nanosheets. A3. 2 g of graphene oxide was added to 120 mL of deionized water and stirred. 1.4 g of modified silicon carbide nanosheets was added and ultrasonicated at 40 kHz for 20 min. The mixture was filtered, washed three times with deionized water, and dried in an oven at 80 ° C for 10 min to obtain a composite material. A4. Add 1 g of carboxymethyl cellulose to 85 mL of deionized water and stir until well combined. Then, add 1.8 g of the composite material and stir for 30 minutes. Then, add 2.5 g of sulfonated lignin and 3 mL of 36% hydrochloric acid. Stir and react at 60°C for 20 minutes. Filter, wash three times with deionized water, and dry in an oven at 70°C for 10 minutes to obtain the reinforcing filler.

[0040] Comparative Example 2 A method for preparing a cemented carbide bearing for deep hard rock drilling comprises the following steps: S1. The tungsten carbide powder, aluminum powder, cobalt powder, nickel powder, iron powder, graphite powder and reinforcing filler are mixed and ball-milled to obtain a mixture; S2. The mixture is placed in a bearing mold and pressed into a preform; S3. Place the prefabricated body in a sintering furnace for sintering, cool to room temperature, and then post-process, grind, and polish to obtain a cemented carbide bearing.

[0041] Wherein, in step S1, the mass ratio of tungsten carbide powder, aluminum powder, cobalt powder, nickel powder, iron powder, graphite powder and reinforcing filler is 100:6:4:6:8:3:6; In step S1, the ball mill is used, the ball-to-material ratio is 10:1, the rotation speed is 300 r / min, and the ball milling time is 20 h; In step S2, the pressing pressure is 350 MPa and the pressing time is 40 s; In step S3, the sintering temperature is 380° C., the sintering time is 4 h, the sintering pressure is 50 Pa, and the sintering is carried out in a nitrogen atmosphere with a nitrogen introduction rate of 60 mL / min.

[0042] The reinforcing filler is specifically prepared by the following steps: A1. Add 0.4 g of tannic acid to 45 mL of ethanol and stir until completely dissolved. Then add 1.4 g of silicon carbide nanosheets and stir at 70°C for 40 min. Filter, wash three times with deionized water, and dry in an oven at 70°C for 10 min to obtain a silicon carbide nanosheet composite. A2. 2 g of silicon carbide nanosheet composite, 3 g of glucose, and 0.6 g of citric acid were added to 110 mL of ethanol. 2 mL of 36% hydrochloric acid was added and stirred at 70°C for 30 min. The mixture was filtered, washed three times with deionized water, and dried in a 70°C oven for 10 min. The mixture was then placed in a tube furnace, and 6 mL of 30% potassium hydroxide solution was added. Nitrogen was introduced and carbonized at 800°C for 4 h. The mixture was cooled to room temperature, removed, washed three times with deionized water, and dried in a 70°C oven for 10 min to obtain modified silicon carbide nanosheets. A3. 2 g of graphene oxide was added to 120 mL of deionized water and stirred. 1.4 g of modified silicon carbide nanosheets was added and ultrasonicated at 40 kHz for 20 min. The mixture was filtered, washed three times with deionized water, and dried in an oven at 80 ° C for 10 min to obtain a composite material. A4. Add 1 g of carboxymethyl cellulose to 85 mL of deionized water and stir until well combined. Then, add 1.8 g of the composite material and stir for 30 minutes. Then, add 2.5 g of sulfonated lignin and 3 mL of 36% hydrochloric acid. Stir and react at 60°C for 20 minutes. Filter, wash three times with deionized water, and dry in an oven at 70°C for 10 minutes to obtain the reinforcing filler.

[0043] Comparative Example 3 A method for preparing a cemented carbide bearing for hard rock deep drilling comprises the following steps: S1. The tungsten carbide powder, aluminum powder, cobalt powder, nickel powder, iron powder, graphite powder and reinforcing filler are mixed and ball-milled to obtain a mixture; S2. The mixture is placed in a bearing mold and pressed into a preform; S3. Place the prefabricated body in a sintering furnace for sintering, cool to room temperature, and then post-process, grind, and polish to obtain a cemented carbide bearing.

[0044] Wherein, in step S1, the mass ratio of tungsten carbide powder, aluminum powder, cobalt powder, nickel powder, iron powder, graphite powder and reinforcing filler is 100:6:4:6:8:3:6; In step S1, the ball mill is used, the ball-to-material ratio is 10:1, the rotation speed is 300 r / min, and the ball milling time is 20 h; In step S2, the pressing pressure is 350 MPa and the pressing time is 40 s; In step S3, the sintering temperature is 380° C., the sintering time is 4 h, the sintering pressure is 50 Pa, and the sintering is carried out in a nitrogen atmosphere with a nitrogen introduction rate of 60 mL / min.

[0045] The reinforcing filler is specifically prepared by the following steps: A1. Add 0.4 g of tannic acid to 45 mL of ethanol and stir until completely dissolved. Then add 1.4 g of silicon carbide nanosheets and stir at 70°C for 40 minutes. Then add 1 g of nano-silicon nitride and continue stirring for 40 minutes. The mixture is filtered, washed three times with deionized water, and dried in a 70°C oven for 10 minutes to obtain silicon carbide nanosheets loaded with nano-silicon nitride. A2. 2 g of graphene oxide was added to 120 mL of deionized water and stirred. 1.4 g of silicon carbide nanosheets loaded with nano-silicon nitride was added and ultrasonicated at 40 kHz for 20 min. The mixture was filtered, washed three times with deionized water, and dried in an oven at 80°C for 10 min to obtain a composite material. A3. Add 1 g of carboxymethyl cellulose to 85 mL of deionized water and stir well. Then add 1.8 g of the composite material and stir for 30 minutes. Then add 2.5 g of sulfonated lignin and 3 mL of 36% hydrochloric acid. Stir and react at 60°C for 20 minutes. Filter, wash three times with deionized water, and dry in an oven at 70°C for 10 minutes to obtain the reinforcing filler.

[0046] Comparative Example 4 A method for preparing a cemented carbide bearing for deep hard rock drilling comprises the following steps: S1. The tungsten carbide powder, aluminum powder, cobalt powder, nickel powder, iron powder, graphite powder and reinforcing filler are mixed and ball-milled to obtain a mixture; S2. The mixture is placed in a bearing mold and pressed into a preform; S3. Place the prefabricated body in a sintering furnace for sintering, cool to room temperature, and then post-process, grind, and polish to obtain a cemented carbide bearing.

[0047] Wherein, in step S1, the mass ratio of tungsten carbide powder, aluminum powder, cobalt powder, nickel powder, iron powder, graphite powder and reinforcing filler is 100:6:4:6:8:3:6; In step S1, the ball mill is used, the ball-to-material ratio is 10:1, the rotation speed is 300 r / min, and the ball milling time is 20 h; In step S2, the pressing pressure is 350 MPa and the pressing time is 40 s; In step S3, the sintering temperature is 380° C., the sintering time is 4 h, the sintering pressure is 50 Pa, and the sintering is carried out in a nitrogen atmosphere with a nitrogen introduction rate of 60 mL / min.

[0048] The reinforcing filler is specifically prepared by the following steps: A1. Add 0.4 g of tannic acid to 45 mL of ethanol and stir until completely dissolved. Then add 1.4 g of silicon carbide nanosheets and stir at 70°C for 40 minutes. Then add 1 g of nano-silicon nitride and continue stirring for 40 minutes. The mixture is filtered, washed three times with deionized water, and dried in a 70°C oven for 10 minutes to obtain silicon carbide nanosheets loaded with nano-silicon nitride. A2. 2 g of silicon nitride nanosheets loaded with silicon carbide nanosheets, 3 g of glucose, and 0.6 g of citric acid were added to 110 mL of ethanol. 2 mL of 36% hydrochloric acid was added and stirred at 70°C for 30 min. The mixture was filtered, washed three times with deionized water, and dried in a 70°C oven for 10 min. The mixture was then placed in a tube furnace, and 6 mL of 30% potassium hydroxide solution was added. Nitrogen was introduced and carbonized at 800°C for 4 h. The mixture was cooled to room temperature, removed, washed three times with deionized water, and dried in a 70°C oven for 10 min to obtain modified silicon carbide nanosheets. A3. Add 1 g of carboxymethyl cellulose to 85 mL of deionized water and stir well. Then add 1.8 g of modified silicon carbide nanosheets and stir for 30 minutes. Then add 2.5 g of sulfonated lignin and 3 mL of 36% hydrochloric acid. Stir and react at 60°C for 20 minutes. Filter, wash three times with deionized water, and dry in an oven at 70°C for 10 minutes to obtain a reinforcing filler.

[0049] Comparative Example 5 A method for preparing a cemented carbide bearing for deep hard rock drilling comprises the following steps: S1. The tungsten carbide powder, aluminum powder, cobalt powder, nickel powder, iron powder, graphite powder and reinforcing filler are mixed and ball-milled to obtain a mixture; S2. The mixture is placed in a bearing mold and pressed into a preform; S3. Place the prefabricated body in a sintering furnace for sintering, cool to room temperature, and then post-process, grind, and polish to obtain a cemented carbide bearing.

[0050] Wherein, in step S1, the mass ratio of tungsten carbide powder, aluminum powder, cobalt powder, nickel powder, iron powder, graphite powder and reinforcing filler is 100:6:4:6:8:3:6; In step S1, the ball mill is used, the ball-to-material ratio is 10:1, the rotation speed is 300 r / min, and the ball milling time is 20 h; In step S2, the pressing pressure is 350 MPa and the pressing time is 40 s; In step S3, the sintering temperature is 380° C., the sintering time is 4 h, the sintering pressure is 50 Pa, and the sintering is carried out in a nitrogen atmosphere with a nitrogen introduction rate of 60 mL / min.

[0051] The reinforcing filler is specifically prepared by the following steps: A1. Add 0.4 g of tannic acid to 45 mL of ethanol and stir until completely dissolved. Then add 1.4 g of silicon carbide nanosheets and stir at 70°C for 40 minutes. Then add 1 g of nano-silicon nitride and continue stirring for 40 minutes. The mixture is filtered, washed three times with deionized water, and dried in a 70°C oven for 10 minutes to obtain silicon carbide nanosheets loaded with nano-silicon nitride. A2. 2 g of silicon nitride nanosheets loaded with silicon carbide nanosheets, 3 g of glucose, and 0.6 g of citric acid were added to 110 mL of ethanol. 2 mL of 36% hydrochloric acid was added and stirred at 70°C for 30 min. The mixture was filtered, washed three times with deionized water, and dried in a 70°C oven for 10 min. The mixture was then placed in a tube furnace, and 6 mL of 30% potassium hydroxide solution was added. Nitrogen was introduced and carbonized at 800°C for 4 h. The mixture was cooled to room temperature, removed, washed three times with deionized water, and dried in a 70°C oven for 10 min to obtain modified silicon carbide nanosheets. A3. 2 g of graphene oxide was added to 120 mL of deionized water and stirred. 1.4 g of modified silicon carbide nanosheets was added and ultrasonicated at 40 kHz for 20 min. The mixture was filtered, washed three times with deionized water, and dried in an oven at 80 ° C for 10 min to obtain a composite material. A4. Add 1 g of carboxymethyl cellulose to 85 mL of deionized water and stir until uniform. Then add 1.8 g of the composite material and stir for 30 minutes. Filter, wash three times with deionized water, and dry in an oven at 70°C for 10 minutes to obtain a reinforcing filler.

[0052] The performance of the cemented carbide bearings prepared in Examples 1-3 and Comparative Examples 1-5 was tested.

[0053] Mechanical property test: The yield strength and tensile strength of the prepared cemented carbide bearings were measured according to GB / T228-2010 (room temperature tensile test method for metallic materials).

[0054] Hardness (HRA) test: The hardness value of the prepared carbide bearing at room temperature was tested according to the standard GB / T3849.1-2015. The prepared carbide bearing was placed at 1000°C to test the hardness value of the carbide bearing at high temperature.

[0055] The test results are shown in Table 1 below.

[0056] Table 1 Performance test of cemented carbide bearings prepared in Examples 1-3 and Comparative Examples 1-5 project Yield strength / MPa Tensile strength / MPa Room temperature hardness (HRA) Hardness at 1000℃(HRA) Example 1 1093 1108 65.9 55.3 Example 2 1105 1119 67.3 57.2 Example 3 1085 1097 63.7 53.1 Comparative Example 1 852 887 48.3 35.1 Comparative Example 2 786 793 45.7 31.7 Comparative Example 3 722 732 40.9 25.3 Comparative Example 4 766 771 43.7 28.6 Comparative Example 5 802 811 47.1 33.5 It can be seen from the data in Table 1 that the cemented carbide bearings prepared in Examples 1-3 have relatively high mechanical properties and temperature resistance.

[0057] In Comparative Example 1, the reinforcing filler prepared by replacing the mass of tannic acid with ethanol was added to the cemented carbide bearing. Its mechanical properties and heat resistance decreased, proving that nano-silicon nitride adhered to the surface of silicon carbide nanosheets through tannic acid. Nano-silicon nitride has a high thermal conductivity, can increase the heat dissipation rate of the cemented carbide bearing, and is conducive to the formation of composite layered materials, thereby improving the mechanical properties of the cemented carbide bearing.

[0058] In Comparative Example 2, reinforcing fillers prepared by replacing nano-silicon nitride with silicon carbide nanosheets were added to cemented carbide bearings. Their mechanical properties and heat resistance decreased, proving that nano-silicon nitride has high thermal conductivity and can improve the heat dissipation rate of cemented carbide bearings, avoiding the problem that as the depth of deep drilling in hard rock increases, the formation temperature is high and heat is difficult to diffuse in the cemented carbide bearings, resulting in deterioration of the cemented carbide bearings and affecting the service life of the cemented carbide bearings.

[0059] In Comparative Example 3, the modified silicon carbide nanosheets are replaced with reinforcing fillers prepared by silicon carbide nanosheets loaded with nano-silicon nitride and added to the cemented carbide bearings. Its mechanical properties and heat resistance are reduced, which proves that the porous carbon structure synthesized on the surface of the silicon carbide nanosheets loaded with nano-silicon nitride can adsorb and fix nano-silicon nitride, thereby preventing the cemented carbide bearings from falling off when the nano-silicon nitride is used under high wear resistance and high pressure, causing cracks in the alloy bearings. During the sintering process, the carbon elements contained in the porous carbon can form a metal carbide reinforcement phase with the molten metal powder, filling the gaps in the alloy bearings, improving the density of the alloy bearings, and enhancing the mechanical strength of the alloy bearings.

[0060] In Comparative Example 4, the composite material is replaced with a reinforcing filler prepared from modified silicon carbide nanosheets and added to the cemented carbide bearing. Its mechanical properties and heat resistance are reduced, proving that the nano-silicon nitride and porous carbon between the layers of the layered composite material formed by intercalating the modified silicon carbide nanosheets into the graphene oxide layers serve as heat conduction channels, further enhancing the heat conduction path of the cemented carbide bearing and improving the heat dissipation performance. The formed layered composite material can absorb and reduce the stress generated by external forces, thereby enhancing the compressive strength of the alloy bearing.

[0061] In Comparative Example 5, a reinforcing filler prepared by replacing sulfonated lignin with carboxymethyl cellulose was added to a cemented carbide bearing, and its mechanical properties and heat resistance decreased, proving that the carboxymethyl cellulose was coated on the surface of the composite material and then reacted with the sulfonated lignin to form a cross-linked network structure coated on the surface of the composite material, which could be adsorbed to the surface of the alloy powder, thereby improving the density of the alloy powder. During the sintering process, the lignin-based cross-linked network structure was carbonized to form a dense cross-linked carbon network structure, which could supplement the carbon content in the alloy and avoid additional carbon loss during the preparation of the alloy bearing due to the high oxygen content, thereby affecting the mechanical properties of the alloy bearing.

[0062] Throughout the specification, references to terms such as "one embodiment," "example," or "specific example" indicate that the specific features, structures, materials, or characteristics described in conjunction with that embodiment or example are included in at least one embodiment or example of the present invention. In this specification, schematic representations of these terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0063] The above contents are merely examples and explanations of the present invention. Those skilled in the art may make various modifications or additions to the described specific embodiments or replace them in similar ways. As long as they do not deviate from the invention or exceed the scope defined by the claims, they should all fall within the scope of protection of the present invention.

Claims

1. A method for preparing a cemented carbide bearing for hard rock deep drilling, characterized in that: The method comprises the following preparation steps: S1. The tungsten carbide powder, aluminum powder, cobalt powder, nickel powder, iron powder, graphite powder and reinforcing filler are mixed and ball-milled to obtain a mixture; S2. The mixture is placed in a bearing mold and pressed into a preform; S3. The preform is placed in a sintering furnace, sintered, cooled to room temperature, and post-processed, ground, and polished to obtain a cemented carbide bearing; The reinforcing filler is obtained by mixing and reacting a composite material with sulfonated lignin after surface treatment with carboxymethyl cellulose; The composite material is prepared by adhering nano-silicon nitride to the surface of silicon carbide nanosheets through tannic acid, then mixing with glucose, carbonizing at high temperature, and then intercalating between graphene oxide layers.

2. The method for preparing a cemented carbide bearing for hard rock deep drilling according to claim 1, characterized in that: The reinforcing filler is specifically prepared by the following steps: A1. Add tannic acid to ethanol and stir until completely dissolved. Add silicon carbide nanosheets and stir. Add nano-silicon nitride and continue stirring. Filter, wash, and dry to obtain nano-silicon nitride-loaded silicon carbide nanosheets. A2. The silicon carbide nanosheets loaded with nano-silicon nitride, glucose, and citric acid were added to ethanol, hydrochloric acid was added, stirred, filtered, washed, dried, potassium hydroxide solution was added, nitrogen was introduced, carbonized, cooled to room temperature, removed, washed, and dried to obtain modified silicon carbide nanosheets; A3. Graphene oxide was added to deionized water, stirred evenly, modified silicon carbide nanosheets were added, and after ultrasonic treatment, the mixture was filtered, washed, and dried to obtain a composite material; A4. Add carboxymethyl cellulose to deionized water and stir evenly. Add the composite material and stir. Add sulfonated lignin and hydrochloric acid. After stirring for reaction, filter, wash, and dry to obtain a reinforcing filler.

3. The method for preparing a cemented carbide bearing for hard rock deep drilling according to claim 2, characterized in that: In step A1, the ratio of the tannic acid, ethanol, silicon carbide nanosheets and nano-silicon nitride is (0.2-0.4) g: (35-45) mL: (1-1.4) g: (0.6-1) g.

4. The method for preparing a cemented carbide bearing for hard rock deep drilling according to claim 2, characterized in that: In step A2, the amount ratio of the silicon carbide nanosheets loaded with nano-silicon nitride, glucose, citric acid, ethanol, hydrochloric acid and potassium hydroxide solution is (1-2) g: (2-3) g: (0.4-0.6) g: (90-110) mL: (1-2) mL: (4-6) mL.

5. The method for preparing a cemented carbide bearing for hard rock deep drilling according to claim 2, characterized in that: In step A3, the ratio of the graphene oxide, deionized water, and modified silicon carbide nanosheets is (1-2) g: (80-120) mL: (1-1.4) g.

6. The method for preparing a cemented carbide bearing for hard rock deep drilling according to claim 2, characterized in that: In step A4, the ratio of the carboxymethyl cellulose, deionized water, composite material, sulfonated lignin and hydrochloric acid is (0.6-1) g: (75-85) mL: (1.4-1.8) g: (1.5-2.5) g: (1-3) mL.

7. The method for preparing a cemented carbide bearing for hard rock deep drilling according to claim 1, characterized in that: In step S1, the mass ratio of the tungsten carbide powder, aluminum powder, cobalt powder, nickel powder, iron powder, graphite powder and reinforcing filler is 100:(5-6):(2-4):(4-6):(6-8):(1-3):(5-6); The ball milling is performed using a ball mill with a ball-to-material ratio of (8-10):1, a rotation speed of 200-300 r / min, and a ball milling time of 15-20 h.

8. The method for preparing a cemented carbide bearing for hard rock deep drilling according to claim 1, characterized in that: In step S2, the pressing pressure is 300-350 MPa, and the pressing time is 30-40 s.

9. The method for preparing a cemented carbide bearing for hard rock deep drilling according to claim 1, characterized in that: In step S3, the sintering temperature is 1300-1380°C, the sintering time is 2-4 hours, the sintering pressure is 40-50 Pa, and the sintering is carried out in a nitrogen atmosphere with a nitrogen introduction rate of 50-60 mL / min.

10. A cemented carbide bearing produced by the method for producing a cemented carbide bearing for hard rock deep drilling according to any one of claims 1 to 9.