A cemented carbide tool and its preparation method

Abstract

The present invention relates to the technical field of cemented carbide tools, and in particular to a cemented carbide tool and a preparation method thereof. The cemented carbide tool comprises the following raw materials: 60-70 parts of WC powder, 8-12 parts of Ni powder, 5-8 parts of Mo2C powder, 2-4 parts of Si3N4 powder, 6-10 parts of a reinforcing phase, and 4-8 parts of an improvement additive. The preparation method comprises the following steps: S1, weighing the raw materials; S2, mixing the WC powder, Ni powder, Mo2C powder, and Si3N4 powder, ball milling, drying, and pressing the mixture in a mold to obtain a green body, placing the green body in a tube furnace, sintering the mixture under nitrogen, and grinding and sieving to obtain an intermediate product; S3, mixing the intermediate product with the reinforcing phase and the improvement additive, drying, pressing the mixture in a mold, and microwave sintering the mixture under argon to obtain the cemented carbide tool. The prepared cemented carbide tool has excellent toughness and wear resistance, can effectively maintain high strength characteristics, and significantly extends the service life of the alloy tool.

Description

Technical Field

[0001] The present invention relates to the technical field of cemented carbide cutting tools, in particular to a cemented carbide cutting tool and a preparation method thereof. Background Art

[0002] In modern manufacturing, cemented carbide cutting tools, thanks to their exceptional hardness, wear resistance, and thermal stability, have become key tools in metal cutting. However, as the manufacturing industry evolves towards high precision, high efficiency, and high reliability, existing cemented carbide cutting tools face numerous challenges. For one thing, facing the widespread adoption of new high-strength, high-hardness materials (such as nickel-based superalloys and ultra-high-strength steels), conventional cemented carbide cutting tools lack the wear resistance and impact toughness to withstand them. During the cutting process, cutting tools are prone to increased wear and edge chipping, resulting in reduced machining accuracy and significantly shortened tool life. For example, in the aerospace industry, machining nickel-based superalloys suffers from extremely low tool life, and frequent tool changes severely impact production efficiency and costs. Furthermore, current manufacturing processes have limitations. Conventional powder metallurgy methods struggle to ensure a uniform distribution of alloy components, leading to internal structural defects and reduced overall tool performance. Therefore, the development of cemented carbide cutting tools with superior performance and advanced manufacturing processes is urgently needed. Summary of the Invention

[0003] In order to solve the above problems, the present invention provides a cemented carbide tool and a preparation method thereof.

[0004] The present invention provides a cemented carbide cutting tool comprising the following raw materials in parts by weight:

[0005] 60-70 parts of WC powder, 8-12 parts of Ni powder, 5-8 parts of Mo2C powder, 2-4 parts of Si3N4 powder, 6-10 parts of strengthening phase, and 4-8 parts of improved additives.

[0006] Preferably, the reinforcing phase is prepared by the following method:

[0007] Disperse cobalt nitrate and yttrium nitrate in deionized water, stir for 10-15 minutes, add a complexing agent, heat and stir for 30-45 minutes, add citric acid, heat to 80-100°C, stir for 5-7 hours, dry, heat treat, cool naturally, grind and sieve to obtain a reinforcing phase.

[0008] Preferably, the strengthening phase comprises the following components in parts by mass: 20-30 parts of cobalt nitrate, 8-12 parts of yttrium nitrate, 1-3 parts of a complexing agent, 10-15 parts of citric acid, and 70-80 parts of deionized water.

[0009] Preferably, the complexing agent is prepared by the following method:

[0010] A1. Disperse tartaric acid in dichloromethane and stir. Then add copper sulfate and p-toluenesulfonyl chloride and stir. Control the temperature at 4-8°C and stir for 4-6 hours. Heat and stir, centrifuge, and vacuum dry to obtain sulfonylated tartaric acid.

[0011] A2. Disperse sulfonylated tartaric acid in deionized water, add graphene oxide and 1-ethyl-(3-dimethylaminopropyl)carbodiimide (EDC), perform ultrasonic dispersion, adjust the pH, heat and stir for 4-6 hours, filter, and freeze-dry to obtain a complexing agent.

[0012] Preferably, in step A1, the following components are included in parts by mass: 8-12 parts of tartaric acid, 15-20 parts of p-toluenesulfonyl chloride, 0.2-0.5 parts of copper sulfate, and 70-80 parts of dichloromethane; in step A2, the following components are included in parts by mass: 5-10 parts of sulfonylated tartaric acid, 2-4 parts of graphene oxide, 60-70 parts of deionized water, and 0.1-0.2 parts of 1-ethyl-(3-dimethylaminopropyl)carbodiimide.

[0013] Preferably, the improved additive is prepared by the following method:

[0014] B1. Add chromium formate and aluminum nitrate to deionized water, stir, add ferric nitrate, stir, then add boric acid, adjust the pH to 3-4, and obtain a mixed salt solution;

[0015] B2. Disperse sodium alginate in deionized water, heat and stir, add calcium chloride, and stir to obtain a sol;

[0016] B3. Add the sol to the mixed salt solution, stir, freeze-dry, and pre-calcine to obtain a composite oxide; microwave sinter the composite oxide to obtain an intermediate, add the intermediate to the etching solution, soak for 5-7 minutes, dry, grind and sieve to obtain an improved additive.

[0017] Preferably, in step B1, the following components are included in parts by mass: 3-6 parts of chromium formate, 5-8 parts of aluminum nitrate, 15-20 parts of ferric nitrate, 0.5-1 part of boric acid, and 120-150 parts of deionized water; in step B2, the following components are included in parts by mass: 2-4 parts of sodium alginate, 4-6 parts of calcium chloride, and 60-70 parts of deionized water; in step B3, the mass ratio of the sol to the mixed salt solution is 30-45:60-70; and the mass ratio of the intermediate to the etching solution is 15-18:25-30.

[0018] The present invention also provides a method for preparing a cemented carbide tool, comprising the following steps:

[0019] S1, weighing the raw materials in parts by mass;

[0020] S2, mixing WC powder, Ni powder, Mo2C powder and Si3N4 powder for 20-30 minutes, ball milling, drying, pressing in a mold to obtain a green body, placing the green body in a tube furnace, sintering under nitrogen, grinding and sieving to obtain an intermediate product;

[0021] S3. Mixing the intermediate product with the reinforcing phase and the improved additive, drying, pressing and forming in a mold, and microwave sintering under argon to obtain a cemented carbide tool.

[0022] Preferably, the sintering treatment in step S2 includes: heating to 500-700°C at a heating rate of 8-15°C / min, and keeping warm for 45-70 minutes; then heating to 800-900°C at a heating rate of 5-8°C / min, and keeping warm for 2-3 hours; then heating to 1000-1100°C at a heating rate of 3-5°C / min, and keeping warm for 1-2 hours.

[0023] Preferably, the microwave sintering in step S3 includes: heating to 800-900°C at a heating rate of 50-80°C / min, keeping warm for 30-45 minutes, controlling the microwave power to 3-6KW, and the frequency to 2.45GHz; heating to 1350-1400°C at a heating rate of 10-20°C / min, keeping warm for 40-60 minutes, controlling the microwave power to 1-2KW, and the frequency to 2.45GHz.

[0024] The present invention has the following beneficial effects:

[0025] The present invention first prepares a sulfonylated tartaric acid derivative through a condensation reaction of tartaric acid and p-toluenesulfonyl chloride; the derivative is covalently coupled with graphene oxide under the action of 1-ethyl-(3-dimethylaminopropyl)carbodiimide to prepare a complexing agent; the hydroxyl and epoxy groups on the surface of the graphene oxide and the sulfonic acid groups introduced by the sulfonylated tartaric acid produce a synergistic effect to form complexing sites with a three-dimensional network structure, which significantly improves the complexing ability for metal ions; at the same time, the lamellar structure of the graphene plays a bridging supporting role in the crack propagation process of the material, effectively inhibiting further extension of the crack; in the strengthening phase preparation stage, cobalt nitrate and yttrium nitrate are first subjected to a coordination reaction with the complexing agent, and citric acid is introduced as an auxiliary ligand. The strengthening phase is formed by regulating the coordination environment, and the carboxyl groups of the citric acid form a more stable multi-nuclear complex with the metal ions. At the same time, the hydroxyl groups of the citric acid and the groups of the complexing agent form a three-dimensional network structure, which promotes the uniform dispersion of the metal ions. The addition of cobalt significantly enhances the toughness and wear resistance of cemented carbide, while yttrium effectively improves the material's hardness and wear resistance by refining the alloy's grain size. The synergistic effect of the two gives cemented carbide superior wear resistance, thereby extending tool life. Furthermore, the combined introduction of zirconium and yttrium optimizes the alloy's microstructure, alleviating internal stress concentration through stress relaxation mechanisms and further improving the material's toughness.

[0026] The present invention mixes chromium formate, aluminum nitrate, ferric nitrate and boric acid to prepare a mixed salt solution; then the solution is mixed with sodium alginate and calcium chloride, and the gel formed by the reaction of sodium alginate and calcium chloride produces a template effect, so that Cr 3+ 、Al 3 + 、Fe 3+ Achieve uniform dispersion at the molecular scale; after pre-calcination, the components react to form composite oxides, significantly enhancing the synergistic effect between the components. Among them, boric acid is converted into borides under high temperature conditions, which on the one hand fills the grain boundaries and inhibits grain migration, and on the other hand can reduce the temperature of the subsequent sintering process. Through freeze-drying and etching processes, the material forms a porous structure, which can enhance the interface wettability of cemented carbide and promote element diffusion, thereby reducing porosity and improving material density and interface bonding strength. The use of microwave sintering technology for composite oxides can further refine the grains, increase the grain boundary density, and improve the strength of the material. The introduction of Cr and Al elements forms a corrosion-resistant phase, and Fe and B elements form a hard phase. The combined effect of the two can effectively resist wear and chemical corrosion during friction, ultimately extending the service life of cemented carbide.

[0027] The present invention is to stir and mix WC powder, Ni powder, Mo2C powder and Si3N4 powder at high speed, sinter them under nitrogen, grind and sieve, stir and mix them with strengthening phase and improved additives at high speed, and microwave sinter them under argon to finally make cemented carbide cutting tools; the low temperature stage can remove moisture and residual organic matter in the raw materials to avoid the generation of pores in the late sintering stage; the medium temperature stage promotes the initial melting of Ni powder and wets WC particles to form local liquid phase diffusion and initially connect the skeleton; the high temperature stage makes MoC solid dissolved in Ni binder phase or WC lattice to form The solid solution strengthening phase is formed, and the Si3N4 particles are evenly dispersed, which inhibits the excessive coarsening of WC grains; microwave heating uses the dielectric loss of the material to directly generate heat, with a fast heating rate and a short holding time in the high temperature section, which can inhibit the abnormal growth of WC grains and promote the uniform penetration of the Ni bonding phase into the WC grain boundary to form a finer two-phase structure; the obtained cemented carbide tool has high density, fine grains and greatly improved mechanical strength; the total time of the two sinterings is shorter than that of traditional single-stage sintering, especially the rapid heating and holding time in the microwave section, which is suitable for industrial mass production. DETAILED DESCRIPTION

[0028] The principles and features of the present invention are described below in conjunction with embodiments. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0029] WC powder was purchased from Shandong Xinbaiyi Metal Materials Co., Ltd. with a particle size of 2-3 μm; Ni powder was purchased from Shanghai Yingfeng Ruihuang Metal Materials Co., Ltd. with a particle size of 0.5-1 μm; Mo2C powder was purchased from Nangong Xingjiu New Materials Technology Co., Ltd. with a particle size of 0.5-2 μm and an effective ingredient of 99.9%; Si3N4 powder was purchased from Ningbo Luofei Nanotechnology Co., Ltd. with a particle size of 0.5-1.5 μm; graphene oxide was purchased from Jiangxi Shuobang New Materials Technology Co., Ltd. with a particle size of 2-3 nm.

[0030] Example 1

[0031] A cemented carbide cutting tool comprising the following raw materials in parts by weight:

[0032] 60 parts of WC powder, 8 parts of Ni powder, 5 parts of Mo2C powder, 2 parts of Si3N4 powder, 6 parts of strengthening phase, and 4 parts of improved additives.

[0033] Wherein, the strengthening phase is prepared by the following method:

[0034] Cobalt nitrate and yttrium nitrate are dispersed in deionized water, stirred at 200 rpm for 10 minutes, a complexing agent is added, heated to 60°C, stirred at 100 rpm for 30 minutes, citric acid is added, heated to 80°C, stirred at 150 rpm for 5 hours, dried at 100°C for 12 hours, and then heat-treated at 2°C / min, heating to 300°C, keeping warm for 2 hours, then heating to 600°C at 5°C / min, keeping warm for 3 hours, naturally cooling, grinding, and passing through a 1000-mesh sieve to obtain a reinforcing phase; in parts by mass, the composition comprises 20 parts of cobalt nitrate, 8 parts of yttrium nitrate, 70 parts of deionized water, 1 part of a complexing agent, and 10 parts of citric acid.

[0035] Wherein, complexing agent is prepared by the following method:

[0036] A1. Disperse tartaric acid in dichloromethane, stir at 100 rpm for 15 min, add copper sulfate and p-toluenesulfonyl chloride, stir for 3 min, control the temperature to 4°C, stir at 150 rpm for 4 h, then raise the temperature to 25°C, stir at 80 rpm for 10 h, centrifuge at 3000 rpm for 5 min, and vacuum dry at 60°C for 12 h to obtain sulfonylated tartaric acid; in parts by mass, the following ingredients: 15 parts of tartaric acid, 8 parts of p-toluenesulfonyl chloride, 0.2 parts of copper sulfate, and 70 parts of dichloromethane;

[0037] A2. Disperse sulfonylated tartaric acid in deionized water, add graphene oxide and 1-ethyl-(3-dimethylaminopropyl)carbodiimide, and disperse under ultrasonication at 30 kHz for 25 min. Adjust the pH to 5.5, heat to 60°C, stir at 100 rpm for 4 h, filter, and freeze-dry at -50°C for 12 h to obtain a complexing agent; in parts by mass, the following ingredients: 5 parts sulfonylated tartaric acid, 2 parts graphene oxide, 60 parts deionized water, and 0.1 part 1-ethyl-(3-dimethylaminopropyl)carbodiimide.

[0038] Wherein, the improved additive is prepared by the following method:

[0039] B1. Chromium formate and aluminum nitrate were added to deionized water, stirred at 100 rpm for 10 min, ferric nitrate was added, stirred at 100 rpm for 15 min, and then boric acid was added to adjust the pH to 3 to obtain a mixed salt solution; by mass, 3 parts of chromium formate, 5 parts of aluminum nitrate, 15 parts of ferric nitrate, 0.5 part of boric acid, and 120 parts of deionized water;

[0040] B2. Disperse sodium alginate in deionized water, heat to 30°C, stir at 80 rpm for 8 minutes, add calcium chloride, and stir for 5 minutes to obtain a sol; by mass, 2 parts sodium alginate, 4 parts calcium chloride, and 60 parts deionized water;

[0041] B3. The sol was added to a mixed salt solution, stirred at 100 rpm for 20 min, freeze-dried at -50°C for 24 h, pre-calcined, heated to 300°C at a heating rate of 8°C / min, kept warm for 2 h, then heated to 700°C at a heating rate of 5°C / min, and kept warm for 1 h; cooled to room temperature to obtain a composite oxide; the composite oxide was microwave sintered at 2.45 GHz and 1200°C at a heating rate of 10°C / min for 30 min, the microwave power was controlled to 1.5 kW, and cooled to room temperature to obtain an intermediate, which was added to an etching solution, soaked for 5 min, dried at 80°C for 4 h, and ground through a 3000 mesh sieve to obtain an improved additive; wherein the mass ratio of the sol to the mixed salt solution was 30:60; the mass ratio of the intermediate to the etching solution was 15:25; and the etching solution was prepared by mixing nitric acid and hydrofluoric acid in a mass ratio of 3:0.4.

[0042] A method for preparing a cemented carbide tool comprises the following steps:

[0043] S1, weighing the raw materials in parts by mass;

[0044] S2. WC powder, Ni powder, Mo2C powder and Si3N4 powder were mixed, stirred at 300 rpm for 20 min, ball milled at 200 rpm for 16 h, the ball-liquid mass ratio was controlled to be 10:2:1, zirconia balls were selected, anhydrous ethanol was selected as the dispersion medium, dried at 70 ° C for 3 h, and pressed in a mold, the molding pressure was controlled to be 10 MPa, and a green body was obtained. The green body was placed in a tubular furnace and sintered under nitrogen. The temperature was increased to 500 ° C at a heating rate of 8 ° C / min and kept warm for 45 min; then the temperature was increased to 800 ° C at a heating rate of 5 ° C / min and kept warm for 2 h; then the temperature was increased to 1000 ° C at a heating rate of 3 ° C / min and kept warm for 1 h, and then the temperature was reduced to room temperature at 2 ° C / min, and the green body was ground through a 3000 mesh sieve to obtain an intermediate product;

[0045] S3. Mix the intermediate product with the reinforcing phase and the improved additives, stir at 600 rpm for 15 minutes, dry at 70°C for 3 hours, press into shape in a mold, control the molding pressure to be 10 MPa, and perform microwave sintering under argon. Heat up to 800°C at a heating rate of 50°C / min, keep warm for 30 minutes, control the microwave power to be 3KW, and the frequency to be 2.45GHz; heat up to 1350°C at a heating rate of 10°C / min, keep warm for 40 minutes, control the microwave power to be 1KW, and the frequency to be 2.45GHz. Cool with the furnace to obtain a cemented carbide tool.

[0046] Example 2

[0047] A cemented carbide cutting tool comprising the following raw materials in parts by weight:

[0048] 70 parts of WC powder, 12 parts of Ni powder, 8 parts of Mo2C powder, 4 parts of Si3N4 powder, 10 parts of strengthening phase, and 8 parts of improved additives.

[0049] Wherein, the strengthening phase is prepared by the following method:

[0050] Cobalt nitrate and yttrium nitrate are dispersed in deionized water, stirred at 300 rpm for 15 minutes, a complexing agent is added, heated to 70°C, stirred at 200 rpm for 45 minutes, citric acid is added, heated to 100°C, stirred at 200 rpm for 7 hours, dried at 110°C for 20 hours, and then heat treated at 4°C / min, heating to 400°C, keeping warm for 3 hours, then heating to 700°C at 10°C / min, keeping warm for 5 hours, naturally cooling, grinding, and passing through a 1000 mesh sieve to obtain a reinforcing phase; by mass, 30 parts of cobalt nitrate, 12 parts of yttrium nitrate, 80 parts of deionized water, 3 parts of a complexing agent, and 15 parts of citric acid.

[0051] Wherein, complexing agent is prepared by the following method:

[0052] A1. Disperse tartaric acid in dichloromethane, stir at 200 rpm for 20 min, add copper sulfate and p-toluenesulfonyl chloride, stir for 5 min, control the temperature to 8°C, stir at 200 rpm for 6 h, then raise the temperature to 30°C, stir at 120 rpm for 12 h, centrifuge at 5000 rpm for 8 min, and vacuum dry at 70°C for 16 h to obtain sulfonylated tartaric acid; by mass: 20 parts of tartaric acid, 12 parts of p-toluenesulfonyl chloride, 0.5 parts of copper sulfate, and 80 parts of dichloromethane;

[0053] A2. Disperse sulfonylated tartaric acid in deionized water, add graphene oxide and 1-ethyl-(3-dimethylaminopropyl)carbodiimide, and ultrasonically disperse at 40 kHz for 35 min. Adjust the pH to 6.5, heat to 70°C, stir at 200 rpm for 6 h, filter, and freeze-dry at -50°C for 18 h to obtain a complexing agent; in parts by mass, the following ingredients: 10 parts sulfonylated tartaric acid, 4 parts graphene oxide, 70 parts deionized water, and 0.2 parts 1-ethyl-(3-dimethylaminopropyl)carbodiimide.

[0054] Wherein, the improved additive is prepared by the following method:

[0055] B1. Chromium formate and aluminum nitrate were added to deionized water, stirred at 150 rpm for 15 min, ferric nitrate was added, stirred at 200 rpm for 20 min, and then boric acid was added to adjust the pH to 4 to obtain a mixed salt solution; by mass, 6 parts of chromium formate, 8 parts of aluminum nitrate, 20 parts of ferric nitrate, 1 part of boric acid, and 150 parts of deionized water;

[0056] B2. Disperse sodium alginate in deionized water, heat to 40°C, stir at 100 rpm for 10 min, add calcium chloride, and stir for 8 min to obtain a sol; by mass, 4 parts of sodium alginate, 6 parts of calcium chloride, and 70 parts of deionized water;

[0057] B3. The sol was added to a mixed salt solution, stirred at 200 rpm for 30 min, freeze-dried at -50°C for 36 h, pre-calcined, heated to 400°C at a heating rate of 12°C / min, kept warm for 3 h, then heated to 800°C at a heating rate of 8°C / min, and kept warm for 2 h; cooled to room temperature to obtain a composite oxide; the composite oxide was microwave sintered at 2.45 GHz and 1200°C at a heating rate of 15°C / min for 45 min, the microwave power was controlled to 1.5 kW, and cooled to room temperature to obtain an intermediate, which was added to an etching solution, soaked for 7 min, dried at 100°C for 6 h, and ground through a 3000 mesh sieve to obtain an improved additive; wherein the mass ratio of the sol to the mixed salt solution was 45:70; the mass ratio of the intermediate to the etching solution was 18:30; and the etching solution was prepared by mixing nitric acid and hydrofluoric acid in a mass ratio of 4:0.5.

[0058] A method for preparing a cemented carbide tool comprises the following steps:

[0059] S1, weighing the raw materials in parts by mass;

[0060] S2. WC powder, Ni powder, Mo2C powder and Si3N4 powder were mixed, stirred at 400 rpm for 30 min, ball milled at 300 rpm for 16 h, the ball-liquid mass ratio was controlled to be 10:2:1, zirconia balls were selected, anhydrous ethanol was selected as the dispersion medium, dried at 80 ° C for 5 h, and pressed in a mold, the molding pressure was controlled to be 15 MPa, and a green body was obtained. The green body was placed in a tube furnace and sintered under nitrogen. The temperature was increased to 700 ° C at a heating rate of 15 ° C / min and kept warm for 70 min; then the temperature was increased to 900 ° C at a heating rate of 8 ° C / min and kept warm for 3 h; then the temperature was increased to 1100 ° C at a heating rate of 5 ° C / min and kept warm for 2 h, and then the temperature was reduced to room temperature at 3 ° C / min, and the green body was ground through a 3000 mesh sieve to obtain an intermediate product;

[0061] S3. Mix the intermediate product with the reinforcing phase and the improved additives, stir at 800 rpm for 20 min, dry at 80°C for 5 h, press into shape in a mold, control the molding pressure to 15 MPa, and perform microwave sintering under argon. Heat up to 900°C at a heating rate of 80°C / min, keep warm for 45 min, control the microwave power to 6 kW, and the frequency to 2.45 GHz; heat up to 1400°C at a heating rate of 20°C / min, keep warm for 60 min, control the microwave power to 2 kW, and the frequency to 2.45 GHz. Cool with the furnace to obtain a cemented carbide tool.

[0062] Example 3

[0063] A cemented carbide cutting tool comprising the following raw materials in parts by weight:

[0064] 65 parts of WC powder, 10 parts of Ni powder, 7 parts of Mo2C powder, 3 parts of Si3N4 powder, 8 parts of strengthening phase, and 6 parts of improved additives.

[0065] Wherein, the strengthening phase is prepared by the following method:

[0066] Cobalt nitrate and yttrium nitrate are dispersed in deionized water, stirred at 260 rpm for 12 minutes, a complexing agent is added, heated to 65°C, stirred at 150 rpm for 40 minutes, citric acid is added, heated to 90°C, stirred at 180 rpm for 6 hours, dried at 105°C for 16 hours, and then heat treated by heating to 350°C at 3°C / min, keeping warm for 2.5 hours, then heating to 650°C at 8°C / min, keeping warm for 4 hours, naturally cooling, grinding, and passing through a 1000 mesh sieve to obtain a reinforcing phase; by mass, 25 parts of cobalt nitrate, 10 parts of yttrium nitrate, 75 parts of deionized water, 2 parts of a complexing agent, and 12 parts of citric acid.

[0067] Wherein, complexing agent is prepared by the following method:

[0068] A1. Disperse tartaric acid in dichloromethane, stir at 150 rpm for 18 min, add copper sulfate and p-toluenesulfonyl chloride, stir for 4 min, control the temperature to 6°C, stir at 180 rpm for 5 h, then raise the temperature to 28°C, stir at 100 rpm for 11 h, centrifuge at 4000 rpm for 7 min, and vacuum dry at 65°C for 14 h to obtain sulfonylated tartaric acid; by mass: 18 parts of tartaric acid, 10 parts of p-toluenesulfonyl chloride, 0.4 parts of copper sulfate, and 75 parts of dichloromethane;

[0069] A2. Disperse sulfonylated tartaric acid in deionized water, add graphene oxide and 1-ethyl-(3-dimethylaminopropyl)carbodiimide, and disperse under ultrasonication at 35 kHz for 30 min. Adjust the pH to 6, heat to 65°C, stir at 150 rpm for 5 h, filter, and freeze-dry at -50°C for 16 h to obtain a complexing agent; in parts by mass, the following ingredients: 8 parts sulfonylated tartaric acid, 3 parts graphene oxide, 65 parts deionized water, and 0.15 parts 1-ethyl-(3-dimethylaminopropyl)carbodiimide.

[0070] Wherein, the improved additive is prepared by the following method:

[0071] B1. Chromium formate and aluminum nitrate were added to deionized water, stirred at 120 rpm for 13 min, ferric nitrate was added, stirred at 150 rpm for 18 min, and then boric acid was added to adjust the pH to 3.5 to obtain a mixed salt solution; by mass, 5 parts of chromium formate, 7 parts of aluminum nitrate, 17 parts of ferric nitrate, 0.8 part of boric acid, and 140 parts of deionized water;

[0072] B2. Disperse sodium alginate in deionized water, heat to 35°C, stir at 90 rpm for 9 minutes, add calcium chloride, and stir for 7 minutes to obtain a sol; by mass, 3 parts of sodium alginate, 5 parts of calcium chloride, and 65 parts of deionized water;

[0073] B3. The sol was added to a mixed salt solution, stirred at 150 rpm for 25 min, freeze-dried at -50°C for 30 h, pre-calcined, heated to 350°C at a heating rate of 10°C / min, kept warm for 2.5 h, then heated to 750°C at a heating rate of 7°C / min, and kept warm for 1.5 h; cooled to room temperature to obtain a composite oxide; the composite oxide was microwave sintered at 2.45 GHz and 1200°C at a heating rate of 13°C / min for 40 min, with the microwave power controlled at 1.5 kW, and cooled to room temperature to obtain an intermediate, which was added to an etching solution, soaked for 6 min, dried at 9°C for 5 h, and ground through a 3000 mesh sieve to obtain an improved additive; wherein the mass ratio of the sol to the mixed salt solution was 40:65; the mass ratio of the intermediate to the etching solution was 17:28; and the etching solution was prepared by mixing nitric acid and hydrofluoric acid in a mass ratio of 3.5:0.45.

[0074] A method for preparing a cemented carbide tool comprises the following steps:

[0075] S1, weighing the raw materials in parts by mass;

[0076] S2. WC powder, Ni powder, Mo2C powder and Si3N4 powder were mixed, stirred at 350 rpm for 25 min, ball milled at 260 rpm for 16 h, the ball-to-liquid mass ratio was controlled to be 10:2:1, zirconia balls were selected, anhydrous ethanol was selected as the dispersion medium, dried at 75 ° C for 4 h, and pressed in a mold, the molding pressure was controlled to be 12 MPa, and a green body was obtained. The green body was placed in a tube furnace and sintered under nitrogen. The temperature was increased to 600 ° C at a heating rate of 12 ° C / min and kept warm for 60 min; then the temperature was increased to 850 ° C at a heating rate of 7 ° C / min and kept warm for 2.5 h; then the temperature was increased to 1050 ° C at a heating rate of 4 ° C / min and kept warm for 1.5 h, then cooled to room temperature at 3 ° C / min, and ground through a 3000 mesh sieve to obtain an intermediate product;

[0077] S3. Mix the intermediate product with the reinforcing phase and the improved additives, stir at 700 rpm for 18 minutes, dry at 75°C for 4 hours, press into shape in a mold, control the molding pressure to be 12 MPa, and perform microwave sintering under argon. Heat up to 850°C at a heating rate of 70°C / min, keep warm for 40 minutes, control the microwave power to be 4 kW, and the frequency to be 2.45 GHz; heat up to 1380°C at a heating rate of 15°C / min, keep warm for 50 minutes, control the microwave power to be 1.5 kW, and the frequency to be 2.45 GHz. Cool with the furnace to obtain a cemented carbide tool.

[0078] Comparative Example 1

[0079] Comparative Example 1 is the same as Example 1, except that the preparation method of the complexing agent is different, as follows:

[0080] The complexing agent is prepared by the following method:

[0081] Tartaric acid was dispersed in deionized water, and graphene oxide and 1-ethyl-(3-dimethylaminopropyl)carbodiimide were added. The mixture was ultrasonically dispersed at 30 kHz for 25 minutes, the pH was adjusted to 5.5, the mixture was heated to 60°C, stirred at 100 rpm for 4 hours, filtered, and freeze-dried at -50°C for 12 hours to obtain a complexing agent; the components, by mass, included 5 parts of tartaric acid, 2 parts of graphene oxide, 60 parts of deionized water, and 0.1 parts of 1-ethyl-(3-dimethylaminopropyl)carbodiimide.

[0082] Comparative Example 2

[0083] Comparative Example 2 is the same as Example 1, except that the preparation method of the reinforcement phase is different, as follows:

[0084] The reinforcement phase was prepared by the following method:

[0085] Cobalt nitrate and yttrium nitrate are dispersed in deionized water, stirred at 200 rpm for 10 minutes, a complexing agent is added, heated to 80°C, stirred at 150 rpm for 5 hours, dried at 100°C for 12 hours, and then heat treated by heating to 300°C at 2°C / min, keeping warm for 2 hours, then heating to 600°C at 5°C / min, keeping warm for 3 hours, naturally cooling, grinding, and passing through a 1000-mesh sieve to obtain a reinforcing phase; by mass, 20 parts of cobalt nitrate, 8 parts of yttrium nitrate, 70 parts of deionized water, and 11 parts of a complexing agent.

[0086] Comparative Example 3

[0087] Comparative Example 3 is the same as Example 1, except that the preparation method of the improved additive is different, as follows:

[0088] The improved additive is prepared by the following method:

[0089] B1. Chromium formate and aluminum nitrate were added to deionized water, stirred at 100 rpm for 10 min, ferric nitrate was added, stirred at 100 rpm for 15 min, and then boric acid was added to adjust the pH to 3 to obtain a mixed salt solution; by mass, 3 parts of chromium formate, 5 parts of aluminum nitrate, 15 parts of ferric nitrate, 0.5 part of boric acid, and 120 parts of deionized water;

[0090] B2. Disperse sodium alginate in deionized water, heat to 30°C, stir at 80 rpm for 8 minutes, add calcium chloride, and stir for 5 minutes to obtain a sol; by mass, 2 parts sodium alginate, 4 parts calcium chloride, and 60 parts deionized water;

[0091] B3. Add the sol to the mixed salt solution, stir at 100 rpm for 20 min, freeze-dry at -50°C for 24 h, pre-calcine, heat to 300°C at a heating rate of 8°C / min, keep warm for 2 h, then heat to 700°C at a heating rate of 5°C / min, keep warm for 1 h; cool to room temperature to obtain a composite oxide; microwave sinter the composite oxide at 2.45 GHz and 1200°C at a heating rate of 10°C / min for 30 min, control the microwave power to 1.5 kW, cool to room temperature, grind through a 3000 mesh sieve to obtain an improved additive; wherein the mass ratio of the sol to the mixed salt solution is 30:60.

[0092] Comparative Example 4

[0093] Comparative Example 4 is the same as Example 1, except that the preparation method of the improved additive is different, as follows:

[0094] The improved additive is prepared by the following method:

[0095] B1. Chromium formate and aluminum nitrate were added to deionized water, stirred at 100 rpm for 10 min, ferric nitrate was added, stirred at 100 rpm for 15 min, and then boric acid was added to adjust the pH to 3 to obtain a mixed salt solution; by mass, 3 parts of chromium formate, 5 parts of aluminum nitrate, 15 parts of ferric nitrate, 0.5 part of boric acid, and 120 parts of deionized water;

[0096] B2. Disperse sodium alginate in deionized water, heat to 30°C, stir at 80 rpm for 8 minutes, add calcium chloride, and stir for 5 minutes to obtain a sol; by mass, 2 parts sodium alginate, 4 parts calcium chloride, and 60 parts deionized water;

[0097] B3. The sol was added to a mixed salt solution, stirred at 100 rpm for 20 min, freeze-dried at -50°C for 24 h, heated to 300°C at a heating rate of 8°C / min, kept warm for 2 h, then heated to 700°C at a heating rate of 5°C / min, kept warm for 1 h; then heated to 1200°C at a heating rate of 5°C / min, kept warm for 30 min, and cooled to room temperature to obtain an intermediate, which was added to an etching solution, soaked for 5 min, dried at 80°C for 4 h, and ground through a 3000 mesh sieve to obtain an improved additive; wherein the mass ratio of the sol to the mixed salt solution was 30:60; the mass ratio of the intermediate to the etching solution was 15:25; and the etching solution was prepared by mixing nitric acid and hydrofluoric acid in a mass ratio of 3:0.4.

[0098] Comparative Example 5

[0099] Comparative Example 5 is the same as Example 1, except that the preparation method of the cemented carbide tool is different, specifically:

[0100] A method for preparing a cemented carbide tool comprises the following steps:

[0101] S1, weighing the raw materials in parts by mass;

[0102] S2. WC powder, Ni powder, Mo2C powder and Si3N4 powder were mixed, stirred at 300 rpm for 20 min, ball milled at 200 rpm for 16 h, the ball-liquid mass ratio was controlled to be 10:2:1, zirconia balls were selected, anhydrous ethanol was selected as the dispersion medium, dried at 70 ° C for 3 h, and pressed in a mold, the molding pressure was controlled to be 10 MPa, and a green body was obtained. The green body was placed in a tubular furnace and sintered under nitrogen. The temperature was increased to 500 ° C at a heating rate of 8 ° C / min and kept warm for 45 min; then the temperature was increased to 800 ° C at a heating rate of 5 ° C / min and kept warm for 2 h; then the temperature was increased to 1000 ° C at a heating rate of 3 ° C / min and kept warm for 1 h, and then the temperature was reduced to room temperature at 2 ° C / min, and the green body was ground through a 3000 mesh sieve to obtain an intermediate product;

[0103] S3. Mix the intermediate product with the reinforcing phase and the improved additives, stir at 600 rpm for 15 min, dry at 70 ° C for 3 h, press into shape in a mold, control the molding pressure to 10 MPa, and sinter under argon. Heat up to 500 ° C at a heating rate of 8 ° C / min and keep warm for 60 min; heat up to 800 ° C at a heating rate of 5 ° C / min and keep warm for 30 min; then heat up to 1350 ° C at a heating rate of 3 ° C / min and keep warm for 40 min. Cool with the furnace to obtain a cemented carbide tool.

[0104] Comparative Example 6

[0105] Comparative Example 6 is the same as Example 1, except that the preparation method of the cemented carbide tool is different, specifically:

[0106] A method for preparing a cemented carbide tool comprises the following steps:

[0107] S1, weighing the raw materials in parts by mass;

[0108] S2. Mix WC powder, Ni powder, Mo2C powder, Si3N4 powder, strengthening phase and improved additives, stir at 300 rpm for 20 min, ball mill at 200 rpm for 16 h, control the ball-liquid mass ratio to be 10:2:1, select zirconia balls, select anhydrous ethanol as the dispersion medium, dry at 70 ° C for 3 h, press into shape in a mold, control the forming pressure to be 10 MPa, obtain a green body, place the green body in a tubular furnace, sintering treatment under nitrogen, heating to 500 ° C at a heating rate of 8 ° C / min, keep warm for 45 min; then heat to 800 ° C at a heating rate of 5 ° C / min, keep warm for 2 h; then heat to 1350 ° C at a heating rate of 3 ° C / min, keep warm for 1 h, and then cool to room temperature at 2 ° C / min to obtain a cemented carbide tool.

[0109] Performance Testing

[0110] The following performance tests were performed on the cemented carbide tools prepared in Examples 1-3 and Comparative Examples 1-6, with the thickness of the cemented carbide tools being controlled to be 3 mm:

[0111] Bending strength: tested according to GB / T232-2010, using the three-point bending method to test the bending strength;

[0112] Impact resistance: The prepared cemented carbide tool was used as a cutting tool to cut 42CrMo steel at a cutting speed of 250 m / min, a cutting amount of 2 mm, and a feed rate of 0.5 mm / rev. The processing length completed when the cutting tool showed obvious defects such as chipping or breakage was used as the evaluation standard. The unit was m. The larger the processing length value, the better the impact resistance of the cemented carbide.

[0113] Wear resistance: The prepared cemented carbide tool was used as a cutting tool to cut 42CrMo steel at a cutting speed of 250 m / min, a cutting amount of 2 mm, and a feed rate of 0.1 mm / rev. The processing length completed when the cutting tool wear reached 0.1 mm was used as the evaluation standard. The unit is m. The larger the processing length value, the better the wear resistance of the cemented carbide.

[0114] Vickers hardness: The room temperature hardness (HV) was measured on a Vickers hardness tester with a load of 30 kg. The fracture toughness (K) was calculated from the radial crack length generated by the Vickers hardness indentation according to the Nihara formula. IC ), unit: MPa·m 1 / 2 ;

[0115] The test results are as follows:

[0116] Table 1 Performance test results

[0117]

[0118] The performance data of Example 1 and Comparative Example 1 show that the strength and hardness of the alloy are significantly improved by sulfonylating the graphene oxide and introducing it into the synthesis system of cemented carbide; the lamellar structure of the sulfonyl-modified graphene forms physical bridges at the grain boundaries, which can effectively inhibit crack propagation.

[0119] According to the test results of Example 1 and Comparative Example 2, the carboxyl groups of citric acid form more stable multinuclear complexes with metal ions, while the hydroxyl groups of citric acid form a three-dimensional network structure with the groups of the complexing agent, which promotes the uniform dispersion of metal ions and avoids agglomeration defects, playing an important role in improving the strength of the alloy.

[0120] The test results of Example 1 and Comparative Example 3 show that the etching process can effectively construct a porous structure and significantly improve the wettability of the alloy interface. The freeze-drying and chemical etching work synergistically to enhance the wettability of the alloy interface and improve the interfacial bonding strength of the material.

[0121] According to the comparative analysis of Example 1 and Comparative Example 4, the use of microwave sintering technology can further refine the grains of the composite oxide, enhance the grain boundary density, and thus improve the strength of the alloy material.

[0122] According to the test results of Example 1 and Comparative Examples 5-6, the hybrid treatment process of nitrogen protected pre-sintering and argon protected microwave sintering is adopted to achieve the coordinated regulation of interface activation and grain refinement, thereby improving the toughness while enhancing the toughness, and further achieving precise control of sintering.

[0123] This specific embodiment is merely an explanation of the present invention and is not intended to limit the present invention. After reading this specification, those skilled in the art may make non-creative modifications to this embodiment as needed. However, as long as such modifications are within the scope of the claims of the present invention, they are protected by patent law.

Claims

1. A cemented carbide tool, characterized in that: Comprising the following raw materials in parts by mass: WC powder 60-70 parts, Ni powder 8-12 parts, Mo2C powder 5-8 parts, Si3N4 powder 2-4 parts, strengthening phase 6-10 parts, improvement additives 4-8 parts; The reinforcing phase is prepared by the following method: Disperse 20-30 parts of cobalt nitrate and 8-12 parts of yttrium nitrate in 70-80 parts of deionized water, stir for 10-15 minutes, add 1-3 parts of complexing agent, heat and stir for 30-45 minutes, add 10-15 parts of citric acid, heat to 80-100°C, stir for 5-7 hours, dry, heat-treat, cool naturally, grind and sieve to obtain a reinforcing phase; Described complexing agent is prepared by the following method: A1. Disperse tartaric acid in dichloromethane and stir. Then add copper sulfate and p-toluenesulfonyl chloride and stir. Control the temperature at 4-8°C and stir for 4-6 hours. Heat and stir, centrifuge, and vacuum dry to obtain sulfonylated tartaric acid. A2. Disperse sulfonylated tartaric acid in deionized water, add graphene oxide and 1-ethyl-(3-dimethylaminopropyl)carbodiimide, disperse under ultrasonication, adjust the pH, heat and stir for 4-6 hours, filter, and freeze-dry to obtain a complexing agent; The improved additive is prepared by the following method: B1. Add chromium formate and aluminum nitrate to deionized water, stir, add ferric nitrate, stir, and then add boric acid to adjust the pH to obtain a mixed salt solution; B2. Disperse sodium alginate in deionized water, heat and stir, add calcium chloride, and stir to obtain a sol; B3, adding the sol to the mixed salt solution, stirring, freeze-drying, and pre-calcining to obtain a composite oxide; The composite oxide is subjected to microwave sintering to obtain an intermediate, which is added into an etching solution, soaked for 5-7 minutes, dried, ground and sieved to obtain an improved additive.

2. A cemented carbide tool according to claim 1, characterized in that: In step A1, the following components are included in parts by mass: 8-12 parts of tartaric acid, 15-20 parts of p-toluenesulfonyl chloride, 0.2-0.5 parts of copper sulfate, and 70-80 parts of dichloromethane; in step A2, the following components are included in parts by mass: 5-10 parts of sulfonylated tartaric acid, 2-4 parts of graphene oxide, 60-70 parts of deionized water, and 0.1-0.2 parts of 1-ethyl-(3-dimethylaminopropyl)carbodiimide.

3. A cemented carbide tool according to claim 1, characterized in that: In step B1, the following components are included in parts by mass: 3-6 parts of chromium formate, 5-8 parts of aluminum nitrate, 15-20 parts of ferric nitrate, 0.5-1 part of boric acid, and 120-150 parts of deionized water; in step B2, the following components are included in parts by mass: 2-4 parts of sodium alginate, 4-6 parts of calcium chloride, and 60-70 parts of deionized water; in step B3, the mass ratio of the sol to the mixed salt solution is 30-45:60-70; and the mass ratio of the intermediate to the etching solution is 15-18:25-30.

4. A method for preparing a cemented carbide tool according to any one of claims 1 to 3, characterized in that: The following steps are involved: S1, weighing the raw materials in parts by mass; S2, mixing WC powder, Ni powder, Mo2C powder and Si3N4 powder for 20-30 minutes, ball milling, drying, pressing in a mold to obtain a green body, placing the green body in a tube furnace, sintering under nitrogen, grinding and sieving to obtain an intermediate product; S3. Mixing the intermediate product with the reinforcing phase and the improved additive, drying, pressing and forming in a mold, and microwave sintering under argon to obtain a cemented carbide tool.

5. The method for preparing a cemented carbide tool according to claim 4, wherein: The sintering treatment in step S2 includes: heating to 500-700°C at a heating rate of 8-15°C / min, and keeping warm for 45-70 minutes; then heating to 800-900°C at a heating rate of 5-8°C / min, and keeping warm for 2-3 hours; then heating to 1000-1100°C at a heating rate of 3-5°C / min, and keeping warm for 1-2 hours.

6. The method for preparing a cemented carbide tool according to claim 4, wherein: The microwave sintering in step S3 includes: heating to 800-900°C at a heating rate of 50-80°C / min, keeping warm for 30-45 minutes, controlling the microwave power to 3-6KW and the frequency to 2.45GHz; heating to 1350-1400°C at a heating rate of 10-20°C / min, keeping warm for 40-60 minutes, controlling the microwave power to 1-2KW and the frequency to 2.45GHz.

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