A method for preparing a nano WC-Co-based composite powder with uniform distribution of inhibitors

Abstract

The application relates to a preparation method of a nano WC-Co-based composite powder with inhibitor uniform distribution, and belongs to the technical field of powder preparation. In the application, tungsten oxide and cobalt oxide with large brittleness are used as raw materials, the raw materials are easily broken in a ball milling process, the superfine and nano particle size of a precursor mixed powder containing an inhibitor and the uniform distribution of the raw materials are ensured, the precursor of the inhibitor is dissolved in anhydrous ethanol, a solution is formed, and the solution is mixed with other raw materials, so that the uniform distribution of the component of the inhibitor element in the precursor mixed powder containing the inhibitor is ensured. Polyethylene glycol is added in the ball milling process, the agglomeration of powder particles is reduced, the friction between the powder particles is reduced, and the flowability of the particles is increased. Through the matching of precursor components, the density of the mixed powder of the inhibitor-containing compact and a stage-by-stage heating process, the full reaction of the compact is ensured, the rapid discharge of generated gas is ensured, and through the further ball milling treatment of the prepared powder, the powder is ensured to have the characteristics of pure phase, small WC particle size and uniform component distribution.

Description

Technical Field

[0001] This invention belongs to the field of powder preparation technology, and particularly relates to a method for preparing nano-WC-Co based composite powder with uniformly distributed inhibitors. Background Technology

[0002] Nanocrystalline cemented carbides, with their significant grain refinement and interface effects, hold promise for breaking the inverse relationship between hardness / strength and toughness in traditional cemented carbides. This means that while significantly improving hardness and flexural strength, they can still maintain or even enhance the material's toughness. Inhibitors can effectively suppress WC grain growth during sintering. The compositional distribution in the sintered powder, especially the uniformity of inhibitor distribution, has a decisive impact on the grain size distribution, microstructure uniformity, and mechanical properties of the cemented carbide samples. If the inhibitor distribution in the powder is uneven, it will not only lead to uneven distribution of inhibitor elements in the cemented carbide preparation, but also, especially, the presence of coarse WC grains in the inhibitor-free regions, result in uneven WC grain size distribution and a large average grain size within the sample, making it difficult to prepare nanocrystalline cemented carbides. Therefore, developing nano-WC-Co composite powders with uniform inhibitor distribution is an important prerequisite for preparing nanocrystalline cemented carbides.

[0003] Traditional methods for preparing nanopowders, such as high-energy ball milling, chemical vapor deposition, spray conversion, and direct reduction-carbonization, yield WC-Co powders with a relatively uniform Co phase distribution. WC-Co powders containing inhibitors are primarily obtained through ball milling and mixing of inhibitors and WC-Co powder. During high-temperature, long-holding liquid-phase sintering (such as vacuum sintering and low-pressure sintering), the additive elements flow with the liquid Co phase in the sintered green body, dissolve in the liquid Co phase, and further re-precipitate on the WC grain surface, ensuring the relatively uniform microstructure of the prepared cemented carbide, including the distribution of inhibitors. However, the high temperature and long holding time during liquid-phase sintering significantly promote WC grain growth, which is highly detrimental to the preparation of nanocrystalline cemented carbides. Low-temperature solid-phase sintering techniques (such as spark plasma sintering and rapid hot pressing) can effectively control WC grain growth while achieving powder densification. However, the microstructure of cemented carbides prepared using WC-Co powder containing inhibitors as raw material is uneven, especially the distribution of the inhibitors. The main reason is that only a small amount of liquid Co or even no liquid Co is formed during solid-state sintering, thus preserving the distribution state in the powder. Therefore, higher requirements are placed on the uniformity of the inhibitor distribution in WC-Co powder. Summary of the Invention

[0004] To address the aforementioned technical issues, a method for preparing nano-WC-Co composite powder with easily controllable composition and process and uniform inhibitor distribution is provided. The composite powder prepared by this method can be sintered in the solid phase to produce cemented carbide with uniform microstructure distribution, providing a new approach for the preparation of nanocrystalline cemented carbide.

[0005] This solution is characterized by including the following steps:

[0006] (1) Use tungsten, cobalt oxide, carbon black, inhibitor precursors (vanadium precursor and chromium precursor) and 1-3 wt.% of polyethylene glycol as raw materials, and weigh them according to the mass ratio.

[0007] (2) The inhibitor precursor weighed in step (1) is mechanically mixed with anhydrous ethanol at a mass ratio of 1:(50~100) at 60~80°C until the inhibitor precursor is completely dissolved or uniformly distributed in the anhydrous ethanol solution.

[0008] (3) Place the raw materials weighed in step (1) and the solution prepared in step (2) into a ball mill, and use the ball mill to mix the raw materials. The ball milling medium is anhydrous ethanol, the ball-to-material ratio (mass ratio) is 5:1~10:1, the ball mill speed is 500~650 r / min, and the ball milling time is 6~10 h. Place the obtained mixed slurry in a drying oven for drying, and after drying, sieve the precursor mixed powder.

[0009] (4) The precursor mixture powder prepared in step (3) is cold-pressed into a green body with a diameter not exceeding 40 mm and a density of 3.0~3.5 g / cm³. 3 ;

[0010] (5) The precursor mixed powder blank described in step (4) is placed in a vacuum furnace for reduction and carbonization reaction. The heating rate is 20 ℃ / min. After heating to 400~450 ℃, it is held for 1 h. Then, the temperature is increased to 900~1100 ℃ at 10~15 ℃ / min and held for 1.5~3 h. The entire heating stage is carried out in an Ar atmosphere.

[0011] (6) The green body obtained after reduction and carbonization in step (5) is ball-milled, and after ball milling and drying, WC-Co composite powder containing inhibitor is obtained. The ball milling process is as follows: anhydrous ethanol is used as the grinding medium, the ball-to-material ratio is 5:1~10:1, the ball mill speed is 600~800 r / min, and the ball milling time is 30~50 h;

[0012] (7) The WC-Co composite powder containing the inhibitor obtained in step (6) is subjected to rapid hot pressing sintering. The specific sintering process is as follows: the temperature is first raised to 600-800 ℃ at a heating rate of 80-100 ℃ / min, held for 3-5 min, and then the temperature is raised to 1100-1250 ℃. The temperature is held for 5-10 min under a pressure of 50-70 MPa. After cooling, the cemented carbide bulk material is prepared.

[0013] In step (1) above, the tungsten oxide is WO. 2.9 Alternatively, WO3 may be used, with cobalt oxide being Co3O4 or Co2O3, and the inhibitor precursor being one or both of VOC2O4 and Cr3(OH)2(CH3COO)7. The prepared composite powder is denoted as WC-xCo-yVC-zCr3C2 composite powder, where x = 3-12 wt.%, y = 0-2.0 wt.%, and z = 0-2.0 wt.%.

[0014] Furthermore, the specific methods for adding tungsten oxide, cobalt oxide, inhibitor precursor, and carbon black in step (1) are as follows:

[0015] When the raw material is WO 2.9 When Co3O4, VOC2O4, and Cr3(OH)2(CH3COO)7 are present, WO3 2.9 The mass fraction of is 117.58(1-xyz)%, the mass fraction of Co3O4 is 136.20x%, the mass fraction of VOC2O4 is 246.2y%, the mass fraction of Cr3(OH)2(CH3COO)7 is 335.2z%, and the mass fraction of carbon black is (15.017-1.44x+13.56y-41.74z)% ~ (23.919+3.25x+52.38y+2.73z)%;

[0016] When the raw material is WO 2.9 When Co3O4, V2O5, and Cr3(OH)2(CH3COO)7 are present, WO3 2.9 The mass fraction of Cr3(OH)2(CH3COO)7 is 117.58(1-xyz)%, the mass fraction of Co3O4 is 136.20x%, the mass fraction of V2O5 is 144.46y%, the mass fraction of Cr3(OH)2(CH3COO)7 is 335.2z%, and the mass fraction of carbon black is (15.017-1.44x+27.89y-41.74z)% ~ (23.919+3.25x+42.83y+2.73z)%;

[0017] When the raw materials are WO3, Co3O4, VOC2O4, and Cr3(OH)2(CH3COO)7, the mass fraction of WO3 is 118.37(1-xyz)%, the mass fraction of Co3O4 is 136.20x%, the mass fraction of VOC2O4 is 246.2y%, the mass fraction of Cr3(OH)2(CH3COO)7 is 335.2z%, and the mass fraction of carbon black is (15.325-1.74x+13.29y-42.02z)% ~ (24.519+2.65x+51.77y+2.13z)%;

[0018] When the raw material is WO 2.9 , Co2O3, V2O5, Cr3(OH)2(CH3COO)7, WO 2.9 The mass fraction of Cr3(OH)2(CH3COO)7 is 117.58(1-xyz)%, the mass fraction of Co2O3 is 140.73x%, the mass fraction of V2O5 is 144.46y%, the mass fraction of Cr3(OH)2(CH3COO)7 is 335.2z%, and the mass fraction of carbon black is (15.017+0.26x+27.89y-41.74z)% ~ (23.919+6.64x+42.83y+2.73z)%;

[0019] When the raw materials are WO3, Co3O4, V2O5, and Cr3(OH)2(CH3COO)7, the mass fraction of WO3 is 118.37(1-xyz)%, the mass fraction of Co3O4 is 136.20x%, the mass fraction of V2O5 is 144.46y%, the mass fraction of Cr3(OH)2(CH3COO)7 is 335.2z%, and the mass fraction of carbon black is (15.325-1.74x+27.59y-42.02z)% ~ (24.519+2.65x+42.22y+2.14z)%;

[0020] When the raw materials are WO3, Co2O3, VOC2O4, and Cr3(OH)2(CH3COO)7, the mass fraction of WO3 is 118.37(1-xyz)%, the mass fraction of Co2O3 is 140.73x%, the mass fraction of VOC2O4 is 246.2y%, the mass fraction of Cr3(OH)2(CH3COO)7 is 335.2z%, and the mass fraction of carbon black is (15.325-0.042x+13.29y-42.02z)% ~ (24.519+6.05x+51.77y+2.14z)%;

[0021] When the raw materials are WO3, Co2O3, V2O5, and Cr3(OH)2(CH3COO)7, the mass fraction of WO3 is 118.37(1-xyz)%, the mass fraction of Co2O3 is 140.73x%, the mass fraction of V2O5 is 144.46y%, the mass fraction of Cr3(OH)2(CH3COO)7 is 335.2z%, and the mass fraction of carbon black is (15.325-0.042x+27.59y-42.02z)% ~ (24.519+6.05x+42.22y+2.14z)%.

[0022] This invention has the following advantages.

[0023] (1) The present invention uses brittle tungsten oxide and cobalt oxide as raw materials, which are easy to break during ball milling, ensuring the ultrafine and nanoparticle size and uniform distribution of raw materials in the mixed powder containing inhibitor precursors; the inhibitor precursor is dissolved in anhydrous ethanol, and after forming a solution, it is mixed with other raw materials to ensure that the composition of the inhibitor element in the mixed powder containing inhibitor precursors is uniformly distributed.

[0024] (2) Adding a certain proportion of polyethylene glycol during the ball milling process of raw material powder can reduce the agglomeration of powder particles, reduce the friction between powder particles, and increase the fluidity of particles. Combined with the ball milling process, and the sieving of the mixed powder containing inhibitor precursors before pressing, the uniformity of the component distribution of the mixed powder containing inhibitor precursors is further ensured.

[0025] (3) By controlling the composition of the precursor, the density of the mixed powder containing the inhibitor and the staged heating process, the reaction of the green body is fully guaranteed and the generated gas is quickly discharged. Combined with the further ball milling treatment of the prepared powder, the composite powder is guaranteed to have the characteristics of pure phase, small WC particle size and uniform component distribution.

[0026] (4) The WC-Co nanopowder prepared by this invention has the characteristics of high purity, small particle size and uniform composition distribution. The tungsten source, cobalt source, carbon source and inhibitor precursor used in the raw materials are commonly used industrial raw materials. The preparation process does not require special instruments, is low in cost, and can quickly realize large-scale industrial production.

[0027] (7) The uniformity of Co phase and additives in powder was verified by rapid sintering technology, which solved the problem of difficult determination of powder components. Attached Figure Description

[0028] Figure 1 TEM images, EDS results, and particle size distribution of the WC-3 wt.%Co-0.7 wt.%VC composite powder prepared in Example 1.

[0029] Figure 2 SEM images and EDS results of the WC-3 wt.%Co-0.7 wt.%VC cemented carbide bulk material prepared in Example 1

[0030] Figure 3 SEM images and EDS results of the WC-3 wt.%Co-0.4 wt.%VC cemented carbide bulk material prepared in Example 2

[0031] Figure 4 SEM image of WC-12 wt.%Co-2.0 wt.%Cr3C2 cemented carbide bulk material prepared in Example 3

[0032] Figure 5 SEM image of WC-12 wt.%Co-0.6 wt.%VC-1.0 wt.%Cr3C2 cemented carbide bulk material prepared in Example 4

[0033] Figure 6 Comparative SEM images and EDS results of the WC-12 wt.%Co-2.0 wt.%Cr3C2 cemented carbide bulk material prepared in Example 1

[0034] Figure 7 Compare the SEM images and EDS results of the WC-3 wt.%Co-0.7 wt.%VC cemented carbide bulk material prepared in Example 2. Detailed Implementation

[0035] Example 1

[0036] The preparation of WC-3 wt.%Co-0.7 wt.%VC composite powder (i.e., WC-xCo-yVC-zCr3C2 composite powder, where x=3wt.%, y=0.7 wt.%, z=0 wt.%) includes the following steps:

[0037] with WO 2.9 Co3O4, VOC2O4, and carbon black were weighed as raw materials in a mass ratio of 100:3.61:1.52:20.89. The weighed VOC2O4 was mechanically mixed with anhydrous ethanol at a mass ratio of 1:80 at 80℃ until the VOC2O4 was completely dissolved. The anhydrous ethanol solution containing VOC2O4, other raw material powders, and 2 wt.% polyethylene glycol (based on the total mass of the raw materials) were placed in a ball mill for ball milling. The ball milling medium was anhydrous ethanol, the ball-to-material ratio was 10:1, the ball mill speed was 550 r / min, and the ball milling time was 10 h. After ball milling, the mixed slurry was placed in a drying oven for drying, baking, and sieving. The obtained powder was cold-pressed into a 40 mm diameter graphite mold, and the density of the cold-pressed green body was 3.2 g / cm³.3 The green body had a smooth, defect-free surface. The green body was placed in a vacuum furnace and heated to 450 °C at a heating rate of 20 °C / min, held for 1 h, then heated to 1100 °C at a heating rate of 15 °C / min, and held for 3 h. All heating stages were carried out in an Ar atmosphere. After cooling, the green body was removed and ball-milled using anhydrous ethanol as the milling medium, with a ball-to-material ratio of 6:1, a milling speed of 600 r / min, and a milling time of 50 h. The ball-milled powder was dried and sieved to obtain the WC-3 wt.%Co-0.7 wt.%VC composite powder. TEM images and EDS results are shown below. Figure 1 As shown. Rapid hot pressing sintering technology was employed, with the temperature first raised to 700 °C at a heating rate of 80 °C / min and held for 5 min, then further raised to 1250 °C and held at 70 MPa for 10 min. After cooling, a cemented carbide bulk material with a density of 98.5% was obtained, and its microstructure is shown below. Figure 2 As shown, Co and VC are uniformly distributed in both the prepared powder and bulk materials.

[0038] Example 2

[0039] The preparation of WC-3 wt.%Co-0.4 wt.%VC-0.6 wt.%Cr3C2 composite powder (i.e., WC-xCo-yVC-zCr3C2 composite powder, where x=3 wt.%, y=0.4 wt.%, z=0.6 wt.%) includes the following steps:

[0040] with WO 2.9 Carbon black, including Co2O3, V2O5, and Cr3(OH)2(CH3COO)7, was used as raw material. The raw materials were weighed in a mass ratio of 100:3.74:0.51:1.78:15.66. The weighed Cr3(OH)2(CH3COO)7 and V2O5 were mechanically mixed with anhydrous ethanol at a mass ratio of 1:90 at 80°C until Cr3(OH)2(CH3COO)7 was completely dissolved and V2O5 was evenly distributed in the ethanol solution. The anhydrous ethanol solution containing Cr3(OH)2(CH3COO)7 and V2O5, along with other raw material powders and 2.5 wt.% polyethylene glycol (based on the total mass of the raw materials), were placed in a ball mill for mixing and grinding. The ball milling medium was anhydrous ethanol, the ball-to-material ratio was 8:1, the ball mill speed was 650 r / min, and the milling time was 10 h. After ball milling, the mixed slurry was placed in a drying oven for drying, baking, and sieving. The resulting powder was then cold-pressed into a 20 mm diameter graphite mold, and the density of the cold-pressed green body was 3.5 g / cm³. 3The billet surface was smooth and free of defects. The billet was placed in a vacuum furnace and heated to 420 °C at a heating rate of 20 °C / min, held for 1 h, then heated to 1050 °C at a heating rate of 15 °C / min and held for 2.5 h. All heating stages were carried out in an Ar atmosphere. After cooling, the billet was removed and ball-milled using anhydrous ethanol as the milling medium at a ball-to-material ratio of 5:1, a milling speed of 800 r / min, and a milling time of 40 h. After ball milling, the powder was dried and sieved to prepare a WC-3wt.%Co-0.4 wt.%VC-0.6 wt.%Cr3C2 composite powder. A rapid hot-pressing technique was used, with the temperature first raised to 750℃ at a rate of 100℃ / min and held for 3 min, then further raised to 1200℃ and held at 60 MPa for 10 min. After cooling, a cemented carbide bulk material with a density of 99.0% was obtained, and its microstructure is as follows: Figure 3 As shown, it can be seen that VC and Cr3C2 are uniformly distributed in the bulk material.

[0041] Example 3

[0042] The preparation of WC-12 wt.%Co-2.0 wt.%Cr3C2 composite powder (i.e., WC-xCo-yVC-zCr3C2 composite powder, where x=12 wt.%, y=0 wt.%, z=2.0 wt.%) includes the following steps:

[0043] Using WO3, Co3O4, Cr3(OH)2(CH3COO)7 and carbon black as raw materials, they were weighed in a mass ratio of 100:16.06:6.59:23.58. The weighed Cr3(OH)2(CH3COO)7 was mechanically mixed with anhydrous ethanol at a mass ratio of 1:(50~100) at 80 °C until the Cr3(OH)2(CH3COO)7 was completely dissolved. The anhydrous ethanol solution containing Cr3(OH)2(CH3COO)7, other raw material powders, and 1 wt.% of polyethylene glycol (based on the total mass of the raw materials) were placed in a ball mill for ball milling. The ball milling media was anhydrous ethanol, the ball-to-material ratio was 10:1, the ball mill speed was 500 r / min, and the milling time was 6 h. After ball milling, the mixed slurry was placed in a drying oven for drying, baking, and sieving. The obtained powder was cold-pressed into shape using a graphite mold with a diameter of 25 mm. The density of the cold-pressed blank was 3.0 g / cm³. 3The green body had a smooth, defect-free surface. The green body was placed in a vacuum furnace and heated to 420 °C at a heating rate of 20 °C / min, held for 1 h, then heated to 1000 °C at a heating rate of 10 °C / min, and held for 1.5 h. All heating stages were carried out in an Ar atmosphere. After cooling, the green body was removed and ball-milled using anhydrous ethanol as the milling medium, with a ball-to-material ratio of 10:1, a milling speed of 500 r / min, and a milling time of 30 h. The ball-milled powder was dried and sieved to prepare WC-12 wt.%Co-2.0 wt.%Cr3C2 composite powder. Rapid hot pressing was used, with the temperature first raised to 600 °C at a heating rate of 80 °C / min and held for 3 min, then further raised to 1150 °C and held at 50 MPa for 8 min. After cooling, a sample with a density of 99.2% was prepared, and its microstructure was as follows: Figure 4 As shown, Cr3C2 is uniformly distributed in the bulk material.

[0044] Example 4

[0045] The preparation of WC-12 wt.%Co-0.6 wt.%VC-1.0 wt.%Cr3C2 composite powder (i.e., WC-xCo-yVC-zCr3C2 composite powder, where x=12 wt.%, y=0.6 wt.%, z=1.0 wt.%) includes the following steps:

[0046] WO3, Co2O3, VOC2O4, Cr3(OH)2(CH3COO)7 and carbon black were used as raw materials and weighed in a mass ratio of 100:16.51:1.44:3.28:23.58. The weighed VOC2O4 and Cr3(OH)2(CH3COO)7V2O5 were mixed with anhydrous ethanol at a mass ratio of 1:60 at 80°C until VOC2O4 and Cr3(OH)2(CH3COO)7 were completely dissolved. The anhydrous ethanol solution containing VOC2O4 and Cr3(OH)2(CH3COO)7, other raw material powders, and 3 wt.% of polyethylene glycol were placed in a ball mill for ball milling. The ball milling media was anhydrous ethanol, the ball-to-material ratio was 5:1, the ball mill speed was 650 r / min, and the ball milling time was 10 h. After ball milling, the mixed slurry was placed in a drying oven for drying, baking, and sieving. The resulting powder was then cold-pressed into a graphite mold with a diameter of 20 mm. The density of the cold-pressed green body was 3.3 g / cm³. 3The billet surface was smooth and free of defects. The billet was placed in a vacuum furnace and heated to 450℃ at a heating rate of 20℃ / min, held for 1 h, and then heated to 900℃ at a heating rate of 10℃ / min, held for 1.5 h. All heating stages were carried out in an Ar atmosphere. After cooling, the billet was removed and ball-milled using anhydrous ethanol as the milling medium at a ball-to-material ratio of 8:1, a milling speed of 800 r / min, and a milling time of 35 h. After ball milling, the powder was dried and sieved to prepare a WC-12 wt.%Co-0.6wt.%VC-1.0 wt.%Cr3C2 composite powder. A rapid hot-pressing technique was used, with the temperature first raised to 800℃ at a rate of 100℃ / min and held for 3 min, then further raised to 1100℃ and held at 70 MPa for 10 min. After cooling, a sample with a density of 98.3% was obtained, and its microstructure was as follows: Figure 5 As shown, it can be seen that VC and Cr3C2 are uniformly distributed in the bulk material.

[0047] Comparative Example 1

[0048] The preparation of WC-12 wt.%Co-2.0 wt.%Cr3C2 powder includes the following steps:

[0049] Commercially purchased WC, Co, and Cr3C2 powders were used as raw materials and mixed in a mass ratio of 96:12:2 using anhydrous ethanol as the milling medium. The ball-to-powder ratio was 10:1, the milling speed was 500 r / min, and the milling time was 30 h. After milling, the powder was dried and sieved to obtain WC-12 wt.%Co-2.0 wt.%Cr3C2 powder. Rapid hot pressing was used to first heat the powder to 600 ℃ at a heating rate of 80 ℃ / min, hold it for 3 min, then continue heating to 1150 ℃, hold it at 50 MPa for 8 min, and after cooling, a cemented carbide bulk material with a density of 98.7% was obtained. Its microstructure is as follows: Figure 6 As shown.

[0050] Comparative Example 2

[0051] The preparation of WC-3 wt.%Co-0.7 wt.%VC powder includes the following steps:

[0052] Using the prepared WC-3 wt.%Co composite powder and VC as raw materials, they were ball-milled and mixed according to the following mass ratio. Anhydrous ethanol was used as the grinding medium, the mass ratio of powder to grinding balls was 6:1, the ball mill speed was 600 r / min, and the ball milling time was 50 h. After ball milling, the mixed slurry was dried in a drying oven and sieved to obtain WC-3 wt.%Co-0.7 wt.%VC mixed powder. A rapid hot pressing technique was used to first heat the material to 700 ℃ at a heating rate of 80 ℃ / min, hold it at that temperature for 5 min, and then continue heating to 1250 ℃, holding it at a pressure of 70 MPa for 10 min. After cooling, a cemented carbide bulk material with a density of 99.4% was obtained, and its microstructure was as follows. Figure 7 As shown.

Claims

1. A method for preparing a uniformly distributed inhibitor nano-WC-Co based composite powder, characterized in that, Includes the following steps: (1) Use tungsten, cobalt oxide, carbon black and inhibitor precursor as raw materials and polyethylene glycol of 1-3 wt.% of the total mass of raw materials as raw materials, and weigh them according to the mass ratio; (2) The inhibitor precursor weighed in step (1) is mechanically mixed with anhydrous ethanol at a mass ratio of 1:(50~100) at 60~80°C until the inhibitor precursor is completely dissolved or uniformly distributed in the anhydrous ethanol solution. (3) Place the raw materials weighed in step (1) and the solution prepared in step (2) into a ball mill and use the ball mill to mix the raw materials. The ball milling medium is anhydrous ethanol, the ball-to-material mass ratio is 5:1~10:1, the ball mill speed is 500~650 r / min, and the ball milling time is 6~10 h. The obtained mixed slurry is placed in a drying oven for drying, and after drying, the precursor mixed powder is sieved. (4) The precursor mixture powder prepared in step (3) is cold-pressed into a green body with a diameter not exceeding 40 mm and a density of 3.0~3.5 g / cm³. 3 ; (5) The precursor mixed powder blank described in step (4) is placed in a vacuum furnace for reduction and carbonization reaction. The heating rate is 20 ℃ / min. After heating to 400~450 ℃, it is held for 1 h. Then, the temperature is increased to 900~1100 ℃ at 10~15 ℃ / min and held for 1.5~3 h. The entire heating stage is carried out in an Ar atmosphere. (6) The blank obtained after reduction and carbonization in step (5) is ball-milled, and after ball milling and drying, WC-Co composite powder containing inhibitor is obtained; the ball milling process is as follows: anhydrous ethanol is used as the grinding medium, the ball-to-material ratio is 5:1~10:1, the ball mill speed is 600~800r / min, and the ball milling time is 30~50 h. (7) The WC-Co composite powder containing the inhibitor obtained in step (6) is subjected to rapid hot pressing sintering. The specific sintering process is as follows: the temperature is first raised to 600-800 ℃ at a heating rate of 80-100 ℃ / min, held for 3-5 min, and then the temperature is raised to 1100-1250 ℃. The temperature is held for 5-10 min under a pressure of 50-70 MPa. After cooling, the cemented carbide bulk material is prepared.

2. The method according to claim 1, characterized in that: In step (1), the tungsten oxide is WO. 2.9 Alternatively, WO3, cobalt oxide is Co3O4 or Co2O3, and the inhibitor precursor is one or both of VOC2O4 and Cr3(OH)2(CH3COO)7; the prepared composite powder is denoted as WC-xCo-yVC-zCr3C2 composite powder, where x=3-12 wt.%, y=0-2.0 wt.%, z=0-2.0 wt.%.

3. The method according to claim 1, characterized in that: The specific methods for adding tungsten oxide, cobalt oxide, inhibitor precursor, and carbon black in step (1) are as follows: When the raw material is WO 2.9 When Co3O4, VOC2O4, and Cr3(OH)2(CH3COO)7 are present, WO3 2.9 The mass fraction of is 117.58(1-xyz)%, the mass fraction of Co3O4 is 136.20x%, the mass fraction of VOC2O4 is 246.2y%, the mass fraction of Cr3(OH)2(CH3COO)7 is 335.2z%, and the mass fraction of carbon black is (15.017-1.44x+13.56y-41.74z)% ~ (23.919+3.25x+52.38y+2.73z)%; When the raw material is WO 2.9 When Co3O4, V2O5, and Cr3(OH)2(CH3COO)7 are present, WO3 2.9 The mass fraction of Cr3(OH)2(CH3COO)7 is 117.58(1-xyz)%, the mass fraction of Co3O4 is 136.20x%, the mass fraction of V2O5 is 144.46y%, the mass fraction of Cr3(OH)2(CH3COO)7 is 335.2z%, and the mass fraction of carbon black is (15.017-1.44x+27.89y-41.74z)% ~ (23.919+3.25x+42.83y+2.73z)%; When the raw materials are WO3, Co3O4, VOC2O4, and Cr3(OH)2(CH3COO)7, the mass fraction of WO3 is 118.37(1-xyz)%, the mass fraction of Co3O4 is 136.20x%, the mass fraction of VOC2O4 is 246.2y%, the mass fraction of Cr3(OH)2(CH3COO)7 is 335.2z%, and the mass fraction of carbon black is (15.325-1.74x+13.29y-42.02z)% ~ (24.519+2.65x+51.77y+2.13z)%; When the raw material is WO 2.9 , Co2O3, V2O5, Cr3(OH)2(CH3COO)7, WO 2.9 The mass fraction of Cr3(OH)2(CH3COO)7 is 117.58(1-xyz)%, the mass fraction of Co2O3 is 140.73x%, the mass fraction of V2O5 is 144.46y%, the mass fraction of Cr3(OH)2(CH3COO)7 is 335.2z%, and the mass fraction of carbon black is (15.017+0.26x+27.89y-41.74z)% ~ (23.919+6.64x+42.83y+2.73z)%; When the raw materials are WO3, Co3O4, V2O5, and Cr3(OH)2(CH3COO)7, the mass fraction of WO3 is 118.37(1-xyz)%, the mass fraction of Co3O4 is 136.20x%, the mass fraction of V2O5 is 144.46y%, the mass fraction of Cr3(OH)2(CH3COO)7 is 335.2z%, and the mass fraction of carbon black is (15.325-1.74x+27.59y-42.02z)% ~ (24.519+2.65x+42.22y+2.14z)%; When the raw materials are WO3, Co2O3, VOC2O4, and Cr3(OH)2(CH3COO)7, the mass fraction of WO3 is 118.37(1-xyz)%, the mass fraction of Co2O3 is 140.73x%, the mass fraction of VOC2O4 is 246.2y%, the mass fraction of Cr3(OH)2(CH3COO)7 is 335.2z%, and the mass fraction of carbon black is (15.325-0.042x+13.29y-42.02z)% ~ (24.519+6.05x+51.77y+2.14z)%; When the raw materials are WO3, Co2O3, V2O5, and Cr3(OH)2(CH3COO)7, the mass fraction of WO3 is 118.37(1-xyz)%, the mass fraction of Co2O3 is 140.73x%, the mass fraction of V2O5 is 144.46y%, the mass fraction of Cr3(OH)2(CH3COO)7 is 335.2z%, and the mass fraction of carbon black is (15.325-0.042x+27.59y-42.02z)% ~ (24.519+6.05x+42.22y+2.14z)%.

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