Cermet powder, method for producing the same, and use thereof

Abstract

The application provides a cermet powder, a preparation method and application thereof, and belongs to the field of magnetic force grinding powder preparation. The application provides a preparation method of a cermet powder, which comprises the following steps: mixing iron powder, nano-tungsten powder, nano-cobalt powder and a plasticizer, and then sequentially performing a degreasing treatment and a diffusion treatment to obtain iron powder coated with tungsten and cobalt; the average particle size of the nano-tungsten powder and the average particle size of the nano-cobalt powder are 0.03-0.125% of the average particle size of the iron powder; mixing the iron powder coated with tungsten and cobalt with excess nano-carbon source, and then sequentially performing a carbonization reaction, an oxidation impurity removal and cooling to obtain the cermet powder; the nano-carbon source comprises carbon black and carbon whiskers; the carbonization treatment is performed in argon-hydrogen mixed gas; the temperature of the carbonization treatment is 1320-1410 DEG C, and the time is 23-34 min.

Description

Technical Field

[0001] This invention relates to the field of magnetic grinding powder preparation, and more particularly to a metal ceramic powder, its preparation method, and its application. Background Technology

[0002] Magnetic abrasive polishing is a flexible machining technique that uses a directional magnetic field to orient magnetic abrasive particles onto the surface of a magnetic brush, thereby grinding and polishing the surface of the workpiece. This technology is characterized by high controllability, simple operation, high processing precision, and low cost, and is widely used for finishing the inner and outer surfaces of shafts, tubes, and irregularly shaped parts.

[0003] The wear resistance and lifespan of magnetic abrasives (generally iron-based powders) are key factors determining the accuracy and efficiency of surface finishing of parts. A common preparation method involves combining hard cutting elements (cBN, Si3N4, Al2O3, etc.) with iron powder. However, due to the differences in physicochemical properties between these hard cutting elements and iron, the interfacial bonding between the iron matrix and the cutting elements is weak, resulting in poor wear resistance. Summary of the Invention

[0004] The purpose of this invention is to provide a metal-ceramic powder, its preparation method, and its application. The metal-ceramic powder prepared by this invention has excellent wear resistance.

[0005] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0006] This invention provides a method for preparing metal-ceramic powder, comprising the following steps:

[0007] Iron powder, nano-tungsten powder, nano-cobalt powder, and plasticizer are mixed and then subjected to degreasing and diffusion treatments in sequence to obtain tungsten and cobalt coated iron powder; the average particle size of the nano-tungsten powder and the average particle size of the nano-cobalt powder are 0.03 to 0.125% of the average particle size of the iron powder.

[0008] The tungsten and cobalt-coated iron powder is mixed with an excess of nano-carbon source and then subjected to carbonization reaction, oxidation to remove impurities and cooling in sequence to obtain the metal ceramic powder.

[0009] The nano carbon source includes carbon black and carbon whiskers;

[0010] The carbonization process is carried out in an argon-hydrogen mixture;

[0011] The carbonization process is carried out at a temperature of 1320–1410°C for 23–34 minutes.

[0012] Preferably, the molar ratio of iron in the iron powder to tungsten in the nano-tungsten powder is 12.5 to 20:1.

[0013] Preferably, the molar ratio of tungsten in the nano-tungsten powder to cobalt in the nano-cobalt powder is 4 to 12:1.

[0014] Preferably, the average particle size of the iron powder is 120-160 μm; the average particle size of the nano-tungsten powder and nano-cobalt powder is independently 50-150 nm.

[0015] Preferably, the plasticizer comprises a 13% (w / w) polyvinyl alcohol aqueous solution; the mass of the polyvinyl alcohol aqueous solution is 3.9-6.5% of the total mass of iron powder, nano-tungsten powder, and nano-cobalt powder.

[0016] Preferably, the degreasing process is performed in a vacuum environment;

[0017] The degreasing treatment is performed at a temperature of 330–440°C for 25–32 minutes.

[0018] Preferably, the diffusion treatment is carried out in a vacuum environment; the temperature of the diffusion treatment is 1120℃~1350℃, and the time is 5~8min.

[0019] Preferably, the molar ratio of tungsten to nano carbon source in the nano tungsten powder is 1:1.1 to 1.7;

[0020] The molar ratio of carbon black to carbon whiskers in the nano carbon source is 0.75–1.8:1; the average particle size of the carbon black is 30–60 nm, the average diameter of the carbon whiskers is 30–50 nm, and the aspect ratio is 500–700:1.

[0021] The present invention also provides a metal-ceramic powder prepared by the preparation method described above, which has a core-shell structure, wherein the core is iron and the shell is a cobalt-tungsten carbide alloy.

[0022] The present invention also provides the application of the metal-ceramic powder described above in the field of magnetic grinding.

[0023] This invention provides a method for preparing cermet powder, comprising the following steps: mixing iron powder, nano-tungsten powder, nano-cobalt powder, and a plasticizer, and then sequentially performing degreasing and diffusion treatments to obtain tungsten and cobalt-coated iron powder; wherein the average particle size of the nano-tungsten powder and the average particle size of the nano-cobalt powder are 0.03–0.125% of the average particle size of the iron powder; mixing the tungsten and cobalt-coated iron powder with an excess of nano-carbon source, and then sequentially performing carbonization reaction, oxidation purification, and cooling to obtain the cermet powder; wherein the nano-carbon source includes carbon black and carbon whiskers; wherein the carbonization treatment is carried out in an argon-hydrogen mixture; wherein the carbonization treatment temperature is 1320–1410°C and the time is 23–34 min. In this invention, the plasticizer enables tungsten powder and cobalt powder to have viscosity and plasticity, facilitating uniform spreading on the surface of iron powder, increasing the coating rate of iron powder, and thus improving the wear resistance of the metal ceramic powder; the carbon source combination of carbon black and carbon whiskers can regulate the grain shape and gradation of the carbonized structure, and work in conjunction with the carbonization process to improve the wear resistance of the shell layer; after carbonization, unreacted carbon sources are removed by oxidation and impurity removal, which can also reduce the interfacial stress generated during the cooling process of carbonization, and improve the interfacial bonding performance and wear resistance of the metal ceramic powder.

[0024] Furthermore, by selecting the optimal molar ratio and particle size of iron powder, tungsten powder, and cobalt powder, powder plasticizing process parameters, degreasing and diffusion treatment processes, molar ratio of tungsten powder, carbon black, and carbon whiskers, carbonization treatment, and oxidation impurity removal, this invention further improves the wear resistance and service life of metal ceramic powder. Moreover, the determination of the above parameters makes the preparation method of this invention have the advantages of high precision in microstructure control, strong process stability and repeatability, and can realize the efficient preparation of core-shell structured metal ceramic powder.

[0025] The results of the examples show that the metal-ceramic powder prepared by this invention has a surface hardness ≥12.5 GPa, a shell thickness of 0.8–1.5 μm, an average core-shell powder particle size of 121–162 μm, and a core-shell structure magnetic powder wear consumption ≤0.6 mg·min in the magnetic grinding experiment on the surface of TC18 titanium alloy. -1 . Detailed Implementation

[0026] This invention provides a method for preparing metal-ceramic powder, comprising the following steps:

[0027] Iron powder, nano-tungsten powder, nano-cobalt powder, and plasticizer are mixed and then subjected to degreasing and diffusion treatments in sequence to obtain tungsten and cobalt coated iron powder; the average particle size of the nano-tungsten powder and the average particle size of the nano-cobalt powder are 0.03 to 0.125% of the average particle size of the iron powder.

[0028] The tungsten and cobalt-coated iron powder is mixed with an excess of nano-carbon source and then subjected to carbonization reaction, oxidation to remove impurities and cooling in sequence to obtain the metal ceramic powder.

[0029] The nano carbon source includes carbon black and carbon whiskers;

[0030] The carbonization process is carried out in an argon-hydrogen mixture;

[0031] The carbonization process is carried out at a temperature of 1320–1410°C for 23–34 minutes.

[0032] This invention involves mixing iron powder, nano-tungsten powder, nano-cobalt powder, and a plasticizer, followed by degreasing and diffusion treatments to obtain tungsten and cobalt-coated iron powder.

[0033] In this invention, the average particle size of the nano-tungsten powder and the average particle size of the nano-cobalt powder are 0.03 to 0.125% of the average particle size of the iron powder, preferably 0.04 to 0.1%, and more preferably 0.06 to 0.08%.

[0034] The molar ratio of iron in the iron powder to tungsten in the nano-tungsten powder is preferably 12.5–20:1, more preferably 15–18:1; the iron powder is preferably atomized iron powder, with an average particle size preferably 120–160 μm, more preferably 140–150 μm; the nano-tungsten powder is preferably reduced powder, with an average particle size preferably 50–150 nm, more preferably 60–120 nm, and even more preferably 80–100 nm.

[0035] In this invention, the molar ratio of tungsten in the nano-tungsten powder to cobalt in the nano-cobalt powder is preferably 4-12:1, more preferably 6-8:1; the nano-cobalt powder is preferably a reduced powder, and the average particle size is preferably 50-150 nm, more preferably 60-120 nm, and even more preferably 80-100 nm.

[0036] In this invention, the plasticizer preferably comprises a polyvinyl alcohol aqueous solution with a mass concentration of 13%; the mass of the polyvinyl alcohol aqueous solution is preferably 3.9-6.5% of the total mass of iron powder, nano-tungsten powder, and nano-cobalt powder, more preferably 4-6%, and even more preferably 4.5-5%.

[0037] Plasticizers can make nano-tungsten powder and nano-cobalt powder sticky and plastic, which makes it easier to spread evenly on the surface of iron powder, improve the coating rate of iron powder, and thus improve the wear resistance of metal ceramic powder.

[0038] When the plasticizer is an aqueous solution of polyvinyl alcohol, the degreasing treatment preferably includes drying and dispersing the resulting mixture; the drying temperature is preferably 140–190°C, more preferably 150–160°C; the dispersion speed is preferably 56–78 r / min. The dispersion treatment prevents particle agglomeration.

[0039] In this invention, the degreasing treatment is preferably carried out in a vacuum environment; the vacuum level of the vacuum environment is preferably 3 × 10⁻⁶. -3 ~5×10 -3 Pa; the temperature of the degreasing treatment is preferably 330–440°C, more preferably 350–400°C, and even more preferably 360–380°C; the time is preferably 25–32 min, more preferably 28–30 min. Plasticizers are removed during the degreasing treatment.

[0040] In this invention, the diffusion treatment is preferably performed in a vacuum environment; the vacuum level of the vacuum environment is preferably 3 × 10⁻⁶. -3 ~5×10 -3 Pa; the diffusion treatment temperature is preferably 1120℃~1350℃, more preferably 1150~1300℃, and even more preferably 1200~1250℃; the time is preferably 5~8min, more preferably 6~7min. The diffusion treatment temperature is conducive to the formation of an interfacial diffusion layer, preventing powder agglomeration and providing a basis for the subsequent second-step in-situ carbonization treatment.

[0041] After obtaining tungsten and cobalt coated iron powder, the present invention mixes the tungsten and cobalt coated iron powder with an excess of nano carbon source and then performs carbonization reaction, oxidation to remove impurities and cooling in sequence to obtain the metal ceramic powder.

[0042] In this invention, the molar ratio of tungsten to carbon source in the nano-tungsten powder is preferably 1:1.1 to 1.7, more preferably 1:1.4 to 1.6; the molar ratio of carbon black to carbon whiskers in the carbon source is preferably 0.75 to 1.8:1, more preferably 0.8 to 1.5:1, and even more preferably 1 to 1.2:1; the average particle size of the carbon black is preferably 30 to 60 nm, more preferably 40 to 50 nm; the average diameter of the carbon whiskers is preferably 30 to 50 nm, more preferably 40 to 45 nm; and the aspect ratio is preferably 500 to 700:1, more preferably 550 to 650:1, and even more preferably 580 to 600:1.

[0043] In this invention, the carbonization process is carried out in an argon-hydrogen mixture, wherein the volume ratio of argon to hydrogen in the argon-hydrogen mixture is preferably 1:0.2; the carbonization temperature is 1320–1410°C, preferably 1350–1400°C, more preferably 1360–1350°C; and the time is 23–34 min, preferably 25–30 min.

[0044] In this invention, the oxidation and impurity removal is preferably carried out in air; the temperature of the oxidation and impurity removal is preferably 410–530°C, more preferably 420–500°C, and even more preferably 450–480°C; the time is preferably 45–63 min, more preferably 50–60 min, and even more preferably 55–58 min. Oxidation and impurity removal can remove excess carbon black powder and carbon whiskers by reacting with oxygen to generate carbon dioxide.

[0045] The present invention also provides a metal-ceramic powder having a core-shell structure, wherein the core is iron and the shell is a cobalt-tungsten carbide alloy.

[0046] In this invention, the thickness of the shell layer is preferably 0.8 to 1.5 μm, more preferably 1 to 1.2 μm; the average particle size of the metal ceramic powder is preferably 121 to 162 μm, more preferably 140 to 150 μm.

[0047] The present invention also provides the application of the metal-ceramic powder described above in the field of magnetic grinding.

[0048] The metal-ceramic powder prepared by this invention has a surface hardness ≥12.5 GPa, a shell thickness of 0.8–1.5 μm, and an average core-shell powder particle size of 121–162 μm. In a magnetic grinding experiment on the surface of TC18 titanium alloy, the wear consumption of the core-shell structure magnetic powder was ≤0.6 mg·min. -1 .

[0049] The following detailed description of the metal ceramic powder, its preparation method, and its application provided by the present invention, with reference to specific embodiments, should not be construed as limiting the scope of protection of the present invention.

[0050] Example 1

[0051] Iron powder, tungsten powder, and cobalt powder were weighed out in a molar ratio of 10.3:0.65:0.07. The iron powder was atomized iron powder with an average particle size of 120 μm, while the tungsten and cobalt powders were reduced powders with an average particle size of 50 nm. A 13% polyvinyl alcohol aqueous solution with a total mass of 3.9% of the iron powder, nano-tungsten powder, and nano-cobalt powder was added and mixed thoroughly. After drying at 140℃, the mixture was dispersed in a stirrer at 56 r / min and then placed under a vacuum of 3 × 10⁻⁶. -3 The pre-alloyed powder was degreased at 330°C for 25 min and then diffused at 1120°C for 5 min in a vacuum furnace.

[0052] 2) Weigh and mix carbon black and carbon whiskers according to the molar ratio of tungsten powder, carbon black and carbon whiskers of 1:0.6:0.5. The average particle size of carbon black is 40 nm, the average diameter of carbon whiskers is 30 nm, and the aspect ratio is 500-550:1. Place the powder in a high-temperature furnace under a protective atmosphere of 1:0.2 argon-hydrogen mixture for surface carbonization treatment. The carbonization temperature and time are 1320℃ and 23 min, respectively. Finally, react in an air atmosphere furnace at 410℃ for 45 min to remove excess carbon black powder and carbon whiskers, and finally obtain core-shell structured magnetic metal ceramic powder.

[0053] Example 2

[0054] 1) Weigh out iron powder, tungsten powder, and cobalt powder in a molar ratio of 12.8:0.84:0.16. The iron powder is atomized iron powder with an average particle size of 160 μm. The tungsten powder and cobalt powder are reduced powders with an average particle size of 150 nm. Add 6.5% of the total mass of iron powder, nano-tungsten powder, and nano-cobalt powder to a 13% polyvinyl alcohol aqueous solution, mix thoroughly, dry at 190℃, and then disperse in a stirrer at a speed of 78 r / min. Finally, load the mixture into a vacuum chamber with a vacuum degree of 3 × 10⁻⁶. -3 The pre-alloyed powder was degreased at 440°C for 32 min and then diffused at 1350°C for 8 min in a vacuum furnace.

[0055] 2) Weigh and mix carbon black and carbon whiskers according to the molar ratio of tungsten powder, carbon black and carbon whiskers of 1:0.9:0.8. The average particle size of carbon black is 60 nm, the average diameter of carbon whiskers is 50 nm, and the aspect ratio is 600-650:1. Place the powder in a high-temperature furnace under a protective atmosphere of 1:0.2 argon-hydrogen mixture for surface carbonization treatment. The carbonization temperature and time are 1410℃ and 34 min, respectively. Finally, react in an air atmosphere furnace at 530℃ for 63 min to remove excess carbon black powder and carbon whiskers, and finally obtain core-shell structured magnetic metal ceramic powder.

[0056] Example 3

[0057] 1) Weigh out iron powder, tungsten powder, and cobalt powder in a molar ratio of 11.3:0.75:0.09. The iron powder is atomized iron powder with an average particle size of 130 μm. The tungsten powder and cobalt powder are reduced powders with an average particle size of 60 nm. Add 4.9% of the total mass of iron powder, nano-tungsten powder, and nano-cobalt powder to a 13% polyvinyl alcohol aqueous solution, mix thoroughly, dry at 150℃, and then disperse in a stirrer at a speed of 66 r / min. Finally, load the mixture into a vacuum chamber with a vacuum degree of 3 × 10⁻⁶. -3 The pre-alloyed powder was degreased at 350°C for 27 min and then diffused at 1160°C for 6 min in a vacuum furnace.

[0058] 2) Weigh and mix carbon black and carbon whiskers according to the molar ratio of tungsten powder, carbon black and carbon whiskers of 1:0.7:0.6. The average particle size of carbon black is 50 nm, the average diameter of carbon whiskers is 40 nm, the aspect ratio is 500-600:1, and the average diameter and length of carbon whiskers are 20 nm and 1.5 μm, respectively. Place the powder in a high-temperature furnace under a protective atmosphere of 1:0.2 argon-hydrogen mixture for surface carbonization treatment. The carbonization temperature and time are 1380℃ and 26 min, respectively. Finally, react in an air atmosphere furnace at 460℃ for 63 min to remove excess carbon black powder and carbon whiskers, and finally obtain core-shell structured magnetic metal ceramic powder.

[0059] Example 4

[0060] 1) Weigh out iron powder, tungsten powder, and cobalt powder in a molar ratio of 12.3:0.84:0.16. The iron powder is atomized iron powder with an average particle size of 140 μm. The tungsten powder and cobalt powder are reduced powders with an average particle size of 70 nm. Add 5.9% of the total mass of iron powder, nano-tungsten powder, and nano-cobalt powder to a 13% polyvinyl alcohol aqueous solution, mix thoroughly, dry at 160℃, and then disperse in a stirrer at 76 r / min. Finally, load the mixture into a vacuum chamber with a vacuum degree of 3 × 10⁻⁶. -3 The pre-alloyed powder was degreased at 370°C for 28 min in a vacuum furnace and then diffused at 1350°C for 7 min.

[0061] 2) Weigh and mix carbon black and carbon whiskers according to the molar ratio of tungsten powder, carbon black and carbon whiskers of 1:0.8:0.7. The average particle size of carbon black is 60 nm, the average diameter of carbon whiskers is 30 nm, and the aspect ratio is 500-530:1. Place the powder in a high-temperature furnace under a protective atmosphere of 1:0.2 argon-hydrogen mixture for surface carbonization treatment. The carbonization temperature and time are 1410℃ and 34 min, respectively. Finally, react in an air atmosphere furnace at 530℃ for 45 min to remove excess carbon black powder and carbon whiskers, and finally obtain core-shell structured magnetic metal ceramic powder.

[0062] The performance parameters of the core-shell structured high-efficiency magnetically ground cermet powders prepared in Examples 1-4 are shown in Table 1:

[0063] Table 1 Performance parameters of core-shell structured high-efficiency magnetically polished cermet powders prepared in Examples 1-4

[0064]

[0065] As can be seen from the table above, the magnetic metal-ceramic powder prepared by this invention has excellent surface hardness and wear resistance. The powder surface hardness is ≥12.5 GPa, the shell thickness is 0.8–1.5 μm, the average particle size of the core-shell powder is 121–162 μm, and the wear consumption of the core-shell structure magnetic powder in the magnetic grinding experiment on the TC18 titanium alloy surface is ≤0.6 mg·min. -1 .

[0066] Example 5

[0067] 1) Weigh out iron powder, tungsten powder, and cobalt powder in a molar ratio of 12.5:0.74:0.14. The iron powder is atomized iron powder with an average particle size of 150 μm. The tungsten powder and cobalt powder are reduced powders with an average particle size of 120 nm. Add 6.5% of the total mass of iron powder, nano-tungsten powder, and nano-cobalt powder to a 13% polyvinyl alcohol aqueous solution, mix thoroughly, dry at 160℃, and then disperse in a stirrer at 78 r / min. Finally, load the mixture into a vacuum chamber with a vacuum degree of 3 × 10⁻⁶. -3 The pre-alloyed powder was degreased at 440°C for 32 min and then diffused at 1320°C for 7 min in a vacuum furnace.

[0068] 2) Weigh and mix carbon black and carbon whiskers according to the molar ratio of tungsten powder, carbon black and carbon whiskers of 1:0.8:0.8. The average particle size of carbon black is 50 nm, the average diameter of carbon whiskers is 30 nm, and the aspect ratio is 530-560:1. Place the mixture in a high-temperature furnace under a protective atmosphere of 1:0.2 argon-hydrogen mixture for surface carbonization treatment. The carbonization temperature and time are 1390℃ and 32 min, respectively. Finally, react in an air atmosphere furnace at 520℃ for 53 min to remove excess carbon black powder and carbon whiskers, and finally obtain core-shell structured magnetic metal ceramic powder.

[0069] Example 6

[0070] 1) Weigh out iron powder, tungsten powder, and cobalt powder in a molar ratio of 12.8:0.65:0.16. The iron powder is atomized iron powder with an average particle size of 160 μm. The tungsten powder and cobalt powder are reduced powders with an average particle size of 110 nm. Add 3.9% of the total mass of iron powder, nano-tungsten powder, and nano-cobalt powder to a 13% polyvinyl alcohol aqueous solution, mix thoroughly, dry at 180℃, and then disperse in a stirrer at 78 r / min. Finally, load the mixture into a vacuum chamber with a vacuum degree of 3 × 10⁻⁶. -3 The pre-alloyed powder was degreased at 440°C for 32 min and then diffused at 1350°C for 8 min in a vacuum furnace.

[0071] 2) Weigh and mix carbon black and carbon whiskers according to the molar ratio of tungsten powder, carbon black and carbon whiskers of 1:0.9:0.7. The average particle size of carbon black is 50 nm, the average diameter of carbon whiskers is 30 nm, and the aspect ratio is 610-630:1. Place the powder in a high-temperature furnace under a protective atmosphere of 1:0.2 argon-hydrogen mixture for surface carbonization treatment. The carbonization temperature and time are 1410℃ and 34 min, respectively. Finally, react in an air atmosphere furnace at 470℃ for 55 min to remove excess carbon black powder and carbon whiskers, and finally obtain core-shell structured magnetic metal ceramic powder.

[0072] Example 7

[0073] 1) Weigh out iron powder, tungsten powder, and cobalt powder in a molar ratio of 12.4:0.65:0.13. The iron powder is atomized iron powder with an average particle size of 140 μm. The tungsten powder and cobalt powder are reduced powders with an average particle size of 150 nm. Add 6.5% of the total mass of iron powder, nano-tungsten powder, and nano-cobalt powder to a 13% polyvinyl alcohol aqueous solution, mix thoroughly, dry at 190℃, and then disperse in a stirrer at a speed of 68 r / min. Finally, load the mixture into a vacuum chamber with a vacuum degree of 3 × 10⁻⁶. -3 The pre-alloyed powder was degreased at 340°C for 28 min and then diffused at 1250°C for 8 min in a vacuum furnace.

[0074] 2) Weigh and mix carbon black and carbon whiskers according to the molar ratio of tungsten powder, carbon black and carbon whiskers of 1:0.9:0.8. The average particle size of carbon black is 50 nm, the average diameter of carbon whiskers is 30 nm, and the aspect ratio is 620-650:1. Place the powder in a high-temperature furnace under a protective atmosphere of 1:0.2 argon-hydrogen mixture for surface carbonization treatment. The carbonization temperature and time are 1410℃ and 23 min, respectively. Finally, react in an air atmosphere furnace at 530℃ for 45 min to remove excess carbon black powder and carbon whiskers, and finally obtain core-shell structured magnetic metal ceramic powder.

[0075] Example 8

[0076] 1) Weigh out iron powder, tungsten powder, and cobalt powder in a molar ratio of 12.2:0.84:0.16. The iron powder is atomized iron powder with an average particle size of 150 μm. The tungsten powder and cobalt powder are reduced powders with an average particle size of 130 nm. Add 6.5% of the total mass of iron powder, nano-tungsten powder, and nano-cobalt powder to a 13% polyvinyl alcohol aqueous solution, mix thoroughly, dry at 170℃, and then disperse in a stirrer at a speed of 56 r / min. Finally, load the mixture into a vacuum chamber with a vacuum degree of 3 × 10⁻⁶ m³ / h. -3 The pre-alloyed powder was degreased at 420°C for 30 min and then diffused at 1320°C for 6 min in a vacuum furnace.

[0077] 2) Weigh and mix carbon black and carbon whiskers according to the molar ratio of tungsten powder, carbon black and carbon whiskers of 1:0.7:0.6. The average particle size of carbon black is 50 nm, the average diameter of carbon whiskers is 40 nm, and the aspect ratio is 500-540:1. Place the powder in a high-temperature furnace under a protective atmosphere of 1:0.2 argon-hydrogen mixture for surface carbonization treatment. The carbonization temperature and time are 1400℃ and 24 min, respectively. Finally, react in an air atmosphere furnace at 430℃ for 63 min to remove excess carbon black powder and carbon whiskers, and finally obtain core-shell structured magnetic metal ceramic powder.

[0078] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a metal-ceramic powder, characterized in that, The steps are as follows: Iron powder, nano-tungsten powder, nano-cobalt powder, and plasticizer are mixed and then subjected to degreasing and diffusion treatments in sequence to obtain tungsten and cobalt-coated iron powder; the average particle size of the nano-tungsten powder and the average particle size of the nano-cobalt powder are 0.03~0.125% of the average particle size of the iron powder; The tungsten and cobalt-coated iron powder is mixed with an excess of nano-carbon source and then subjected to carbonization reaction, oxidation to remove impurities and cooling in sequence to obtain the metal ceramic powder. The nano carbon source includes carbon black and carbon whiskers; The carbonization reaction is carried out in an argon-hydrogen mixture; the volume ratio of argon to hydrogen in the argon-hydrogen mixture is 1:0.

2. The carbonization reaction is carried out at a temperature of 1320~1410℃ for 23~34 minutes.

2. The preparation method according to claim 1, characterized in that, The molar ratio of iron in the iron powder to tungsten in the nano-tungsten powder is 12.5~20:

1.

3. The preparation method according to claim 1, characterized in that, The molar ratio of tungsten in the nano-tungsten powder to cobalt in the nano-cobalt powder is 4~12:

1.

4. The preparation method according to claim 1, characterized in that, The average particle size of the iron powder is 120~160μm; the average particle size of the nano-tungsten powder and nano-cobalt powder is independently 50~150nm.

5. The preparation method according to any one of claims 1 to 3, characterized in that, The plasticizer comprises a 13% polyvinyl alcohol aqueous solution; the mass of the polyvinyl alcohol aqueous solution is 3.9-6.5% of the total mass of iron powder, nano-tungsten powder, and nano-cobalt powder.

6. The preparation method according to claim 1, characterized in that, The degreasing process is carried out in a vacuum environment; the temperature of the degreasing process is 330~440℃, and the time is 25~32min.

7. The preparation method according to claim 1, characterized in that, The diffusion process is carried out in a vacuum environment; the temperature of the diffusion process is 1120℃~1350℃, and the time is 5~8 minutes.

8. The preparation method according to claim 1, characterized in that, The molar ratio of tungsten to nano-carbon source in the nano-tungsten powder is 1:1.1~1.7; The molar ratio of carbon black to carbon whiskers in the nano carbon source is 0.75~1.8:1, the average particle size of the carbon black is 30~60nm, the average diameter of the carbon whiskers is 30~50nm, and the aspect ratio is 500~700:

1.

9. The metal-ceramic powder prepared by the preparation method according to any one of claims 1 to 8, characterized in that, It has a core-shell structure, wherein the core is iron and the shell is a cobalt-tungsten carbide alloy.

10. The application of the metal-ceramic powder of claim 9 in the field of magnetic grinding.

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