An alloy powder and a method of making the same

Abstract

This invention discloses an alloy powder and its preparation method, belonging to the field of alloy powder preparation technology. The invention initially synthesizes a uniform WC-TiC composite phase through a first mixing, ball milling, and sintering process. Then, an electric arc micro-explosion process is used to obtain a first mixed material powder, ensuring uniform mixing of WC-TiC and laying the foundation for subsequent uniform composite formation. Subsequently, the WC-TiC mixed phase and other additives undergo a second ball milling and high-temperature sintering to achieve sufficient diffusion and alloying of each component. Finally, a second electric arc micro-explosion process efficiently breaks down and spheroidizes the dense alloy block into spherical powder. A third low-temperature reduction process eliminates internal stress in the powder and stabilizes the microstructure, thereby comprehensively ensuring the sphericity, compositional uniformity, and low oxygen content of the final powder product. The obtained alloy powder can be used to prepare alloy metal coatings with uniform composition, low segregation, crack resistance, low oxygen content, and good corrosion resistance through a cladding process.

Description

Technical Field

[0001] This invention relates to the field of alloy powder preparation technology, and in particular to an alloy powder and its preparation method. Background Technology

[0002] Cemented carbide, due to its high hardness, wear resistance, and good red hardness, is widely used in machining, mining tools, and wear-resistant parts. Traditional cemented carbide is typically based on tungsten-cobalt (WC-Co) alloys and is prepared using powder metallurgy. However, with the increasing demands for processing efficiency and service life in modern industry, especially when machining tough materials such as steel, conventional WC-Co alloys, due to their high affinity for steel and susceptibility to crater wear, can no longer meet the stringent application requirements. Therefore, adding titanium carbide (TiC) to the WC matrix to improve the alloy's oxidation resistance, hardness, and corrosion resistance has become an important material system suitable for the precision machining of steel.

[0003] However, WC, TiC, and some additives are difficult to mix uniformly, making it impossible to guarantee a high sphericity of the alloy powder. Furthermore, problems such as component segregation, high oxygen content, and susceptibility to corrosion are common. Therefore, there is an urgent need to develop a cemented carbide powder with uniform composition, high sphericity, low oxygen content, and self-fluxing properties. Applying such an alloy powder to the cladding process would facilitate the preparation of alloy coatings with uniform composition, low oxygen content, resistance to cracking, and good corrosion resistance. Summary of the Invention

[0004] Based on this, the present invention mainly provides an alloy powder and its preparation method, which solves the technical problems of uneven mixing of various components in the raw alloy powder, high oxygen content, easy material segregation, uneven composition, low hardness, and poor corrosion resistance of the prepared cladding layer product when preparing cladding layer products through cladding processing.

[0005] To achieve the above objectives, the present invention provides a method for preparing alloy powder, comprising the following steps:

[0006] S10. Mix WC and TiC, perform a first mixing ball milling and a first sintering to obtain a first mixed material, and perform a first electric arc micro-explosion on the first mixed material to obtain the first mixed material powder.

[0007] S20. The first mixed material powder, Co, and Si are mixed, and then subjected to a second mixing ball milling and a second sintering to obtain a second mixed material. The second mixed material is then subjected to a second electric arc micro-explosion to obtain a second mixed material powder.

[0008] S30. The second mixed material powder is subjected to reduction treatment to obtain alloy powder.

[0009] In some embodiments of the present invention, the mass ratio of WC to TiC is (1:0.1) to (1:1).

[0010] In some embodiments of the present invention, the average sphere diameter of WC is 0.1 μm to 10 μm, and the average sphere diameter of TiC is 1 / 10 of the average sphere diameter of WC.

[0011] In some embodiments of the present invention, the mass ratio of the first mixed material powder to the Co and Si is 100:(40~60):(4~10).

[0012] In some embodiments of the present invention, the temperature of the first sintering is 1200℃~1300℃, and the time of the first sintering is 4h~5h.

[0013] In some embodiments of the present invention, the temperature of the second sintering is 1400℃~1500℃; the time of the second sintering is 6h~10h.

[0014] In some embodiments of the present invention, the temperature of the reduction treatment is 850°C to 950°C, and the time of the reduction treatment is 3h to 4h.

[0015] In some embodiments of the present invention, in step S20, the first mixed material powder, Co, Si and pore-forming agent are mixed and then subjected to the second ball milling treatment, wherein the pore-forming agent includes ammonium bicarbonate.

[0016] In some embodiments of the present invention, during the second arc micro-explosion, the second mixed material is formed into droplets, and the droplets are cooled to obtain powder of the second mixed material.

[0017] The cooling includes a coolant, which includes at least one of Na2CO3 aqueous solution and K2CO3 aqueous solution.

[0018] The present invention also provides an alloy powder prepared by the method described above.

[0019] The beneficial effects that this invention can achieve are:

[0020] This invention initially synthesizes a uniform WC-TiC composite phase through a first mixing, ball milling, and sintering process. Then, an electric arc micro-explosion process is used to obtain a first mixed material powder, ensuring uniform mixing of WC-TiC and laying the foundation for subsequent uniform composite formation. Subsequently, the first mixed material powder is ball-milled and sintered at high temperature with Co and Si to achieve sufficient diffusion and alloying of each component. Finally, a second electric arc micro-explosion process efficiently breaks down and spheroidizes the dense alloy block into spherical alloy powder. A third low-temperature reduction process eliminates internal stress in the powder and stabilizes the microstructure, thereby comprehensively ensuring the sphericity, compositional uniformity, and overall performance of the final alloy powder.

[0021] The prepared alloy powder can be instantly liquefied and wetted in the subsequent cladding process to form a uniform alloy coating with few cracks and less material segregation. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0023] Figure 1 This is a schematic diagram of the preparation process of alloy powder according to an embodiment of the present invention.

[0024] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0025] It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0026] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0027] In this invention, descriptions involving "first," "second," etc., are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. Furthermore, the technical solutions of the various embodiments can be combined with each other, but only on the basis of being achievable by those skilled in the art. If the combination of technical solutions is contradictory or impossible to implement, such a combination should be considered non-existent and not within the scope of protection claimed by this invention.

[0028] In view of this, the present invention provides a method for preparing alloy powder, referring to... Figure 1 This includes the following steps:

[0029] S10. Mix WC and TiC, perform a first mixing ball milling and a first sintering to obtain a first mixed material, and perform a first electric arc micro-explosion on the first mixed material to obtain the first mixed material powder.

[0030] S20. The first mixed material powder, Co, and Si are mixed, and then subjected to a second mixing ball milling and a second sintering to obtain a second mixed material. The second mixed material is then subjected to a second electric arc micro-explosion to obtain a second mixed material powder.

[0031] S30. The second mixed material powder is subjected to reduction treatment to obtain alloy powder.

[0032] Step S10 involves pre-spheroidizing via "WC-TiC ball milling-sintering-arc micro-explosion". First, a high-hardness carbide skeleton is formed by sintering. Then, the brittle alloy block is directly broken into a first mixed material powder with high sphericity, low oxygen content, and uniform mixing of WC and TiC by instantaneous melting and high-speed cooling through arc micro-explosion.

[0033] The temperature of the first sintering is 1200℃~1300℃, and the time of the first sintering is 4h~5h. The first mixed material after sintering is in the form of an alloy block.

[0034] In some embodiments, the first arc micro-explosion includes the following steps: connecting a first mixed material to the positive terminal of a pulse power supply, connecting a graphite electrode to the negative terminal of a pulse power supply, applying a current between the positive and negative terminals of the pulse power supply to form an arc discharge, and forming a molten pit on the surface of the first mixed material; then introducing a high-pressure fluid between the positive and negative terminals of the pulse power supply, allowing the high-pressure fluid to flow through the molten pit, causing the molten pit to generate small droplets, and cooling the small droplets to obtain powder of the first mixed material.

[0035] In some embodiments, the discharge current in the first arc micro-explosion is 300A~350A, which makes it easy to form a molten pit on the surface of the first mixed material.

[0036] In some embodiments, during the first arc micro-explosion, the relative gap between the positive and negative electrodes of the pulse power supply is 0.03 mm to 0.05 mm. Within this range, it is beneficial to precisely control the formation of the molten pit, and the arc is more stable, making the formation and maintenance of the molten pit more controllable. It also helps to avoid excessive expansion or instability of the molten pit, thereby improving the compositional uniformity and sphericity of the final alloy powder.

[0037] In this invention, during the first arc micro-explosion, the impact of high-pressure fluid on the molten pit can induce the formation of tiny metal droplets. These droplets, after flying away from the molten zone, will rapidly cool to obtain primary alloy powder.

[0038] In some embodiments, during the first arc micro-explosion, the high-pressure fluid includes high-pressure water and / or high-pressure gas. The impact of the high-pressure water and high-pressure gas on the molten pit can rapidly cool the metal droplets, which helps to form a fine grain structure, improves the strength, toughness and sphericity of the material, and can precisely control the deposition position and shape of the small droplets by precisely controlling the parameters of the high-pressure water and high-pressure gas. It is also less likely to react with the components in the first mixed material, resulting in the generation of impurities.

[0039] In some embodiments, during the first arc micro-explosion, the high-pressure fluid is a high-pressure gas, including high-pressure air, high-pressure nitrogen, high-pressure argon, and / or high-pressure helium. These types of high-pressure gases are not prone to reacting with the components in the first mixed material, thus preventing the generation of impurities.

[0040] In some embodiments, during the first arc micro-explosion, the high-pressure fluid is high-pressure water flow, with an applied pressure of 1 MPa to 2 MPa and a flow rate of 50 L / min to 60 L / min. This promotes the dispersion of small metal droplets, prevents the small metal droplets from sticking together before cooling to form alloy powder, improves the sphericity of the final alloy powder, and controls it to obtain a smaller particle size.

[0041] In some embodiments, the first arc micro-explosion is carried out in an inert gas environment, such as an argon or nitrogen atmosphere, which can reduce the oxidation of the metal droplets during the cooling process and provide a more uniform cooling environment, thereby helping to improve the sphericity of the first mixed material powder.

[0042] In some embodiments, during the first arc micro-explosion, the relative horizontal movement of the negative and positive electrodes of the pulse power supply can be adjusted to sequentially form numerous melting pits on the horizontal surface of the first mixed material facing the electrode direction, causing the flying material to become powder of the first mixed material. The material of the first mixed material horizontal surface layer will be peeled off into numerous powders of the first mixed material.

[0043] In some embodiments, during the first arc micro-explosion, the relative vertical movement of the negative and positive terminals of the pulse power supply can be adjusted to allow the first mixed material to be peeled off layer by layer into countless first mixed material powders until the entire first mixed material is completely peeled off, thereby improving the utilization rate of the material.

[0044] In some embodiments, during the first arc micro-explosion, the electrode is fed horizontally relative to the first mixed material at a speed of 600 mm / min and vertically at a speed of 0.5 mm / min.

[0045] In some embodiments, the average sphere diameter of WC is 0.1 μm to 10 μm.

[0046] In some embodiments, the average sphere diameter of TiC is 1 / 10 of the average sphere diameter of WC.

[0047] In this invention, Co can enhance the bonding force between the second mixed materials, thereby ultimately improving the toughness and impact resistance of the alloy powder, while Si can inhibit grain growth, which is beneficial to obtaining finer grains and improving the strength and toughness of the alloy powder. In addition, Si can also improve the fluidity of the liquid phase during the second sintering process, promote the uniform mixing and densification of the alloy, and facilitate the final obtaining of alloy powder with uniform composition.

[0048] In some embodiments, the average particle size of Co is 100 μm to 200 μm.

[0049] In some embodiments, the average particle size of Si is 100 μm to 200 μm.

[0050] In some embodiments, the mass ratio of the first mixed material powder to Co and Si is 100:(40~60):(4~10), which is beneficial to improve the hardness, wear resistance, compressive strength and thermal stability of the final product alloy powder, while obtaining better surface integrity and improving sphericity. As a raw material, it can be used in laser cladding and plasma cladding processes to easily obtain cladding layer products with uniform composition.

[0051] In some embodiments, the temperature of the second sintering is 1400℃~1500℃. Under the above temperature conditions, it is beneficial to promote the uniform mixing of the first mixed material powder, Co, and Si, and obtain a blocky second mixed material with uniform composition. After the second mixed material is subjected to arc micro-explosion treatment, it is easy to obtain a second mixed material powder with uniform composition.

[0052] In some embodiments, the second sintering time is 6h to 10h.

[0053] In some embodiments, in step S20, the first mixed material powder, Co, Si, and ammonium bicarbonate are mixed, and then subjected to the second ball milling treatment. The addition of ammonium bicarbonate can create uniform pores within the second mixed material. During the second arc micro-explosion process, when the material melts instantaneously into droplets in the arc, the pores within the second mixed material block can reduce the surface tension and viscosity of the droplets, thereby greatly promoting the sphericification process of the droplets. This makes it easier for the droplets to shrink into spherical shapes with a high sphericity under the action of surface tension, effectively improving the sphericity of the final alloy powder. Simultaneously, the channels formed by ammonium bicarbonate after the second sintering provide pathways for the uniform flow and distribution of the Co metal phase and Si in the matrix, further promoting the homogenization of the alloy composition. Furthermore, during the reduction treatment, these pores shrink or disappear, contributing to the formation of a dense and uniform internal structure of the powder particles, thereby synergistically improving the overall performance of the final alloy powder.

[0054] In some embodiments, the mass ratio of the first mixed material powder to Co, Si and ammonium bicarbonate is 100:(40~60):(4~10):(1~2).

[0055] In some embodiments, the second arc micro-explosion includes the following steps: connecting the second mixed material to the positive terminal of the pulse power supply, connecting the graphite electrode to the negative terminal of the pulse power supply, applying current between the positive and negative terminals of the pulse power supply to form an arc discharge, and forming a molten pit on the surface of the second mixed material; then introducing a high-pressure fluid between the positive and negative terminals of the pulse power supply, allowing the high-pressure fluid to flow through the molten pit, causing the molten pit to generate small droplets, and cooling the small droplets to obtain the second mixed material powder.

[0056] In some embodiments, during the second arc micro-explosion, the discharge current is greater than or equal to 300A, which makes it easy to form a molten pit on the surface of the second mixed material.

[0057] In some embodiments, during the second arc micro-explosion, the relative gap between the positive and negative electrodes of the pulse power supply is 0.03 mm to 0.05 mm. Within this range, it is beneficial to precisely control the formation of the molten pit, and the arc is more stable, making the formation and maintenance of the molten pit more controllable. It also helps to avoid excessive expansion or instability of the molten pit, thereby improving the compositional uniformity and sphericity of the alloy powder obtained subsequently.

[0058] In some embodiments, in the second arc micro-explosion, the high-pressure fluid includes high-pressure water flow and / or high-pressure gas. The impact of the high-pressure water flow and high-pressure gas on the molten pit can rapidly cool the metal droplets, which helps to form a fine grain structure, improves the strength, toughness and sphericity of the material, and can precisely control the deposition position and shape of the small droplets by precisely controlling the parameters of the high-pressure water flow and high-pressure gas. It is also less likely to react with the components in the second mixed material, resulting in the generation of impurities.

[0059] In some embodiments, in the second arc micro-explosion, the high-pressure fluid is a high-pressure gas, including high-pressure air, high-pressure nitrogen, high-pressure argon and / or high-pressure helium. The above types of high-pressure gases are not likely to react with the components in the first mixed material to generate impurities.

[0060] In some embodiments, during the second arc micro-explosion, the high-pressure fluid is high-pressure water flow, with an applied pressure of 1 MPa to 2 MPa and a flow rate of 50 L / min to 60 L / min. This promotes the dispersion of small metal droplets, prevents the small metal droplets from sticking together before cooling to form alloy powder, improves the sphericity of the alloy powder, and controls it to obtain a smaller particle size.

[0061] In some embodiments, the second arc micro-explosion is carried out in an inert gas environment, such as an argon or nitrogen atmosphere, which can reduce the oxidation of the metal droplets during the cooling process and provide a more uniform cooling environment, thus helping to improve the sphericity of the metal powder.

[0062] In some embodiments, during the second arc micro-explosion, the relative horizontal movement of the negative and positive electrodes of the pulse power supply can be adjusted to sequentially form numerous melting pits on the horizontal surface of the second mixed material facing the electrode direction, causing the flying material to become second mixed material powder. The material on the horizontal surface of the second mixed material will be peeled off into numerous second mixed material powders.

[0063] In some embodiments, during the second arc micro-explosion, the relative vertical movement of the negative and positive terminals of the pulse power supply can be adjusted to allow the second mixed material to be peeled off layer by layer into countless powders until the entire second mixed material is completely peeled off, thereby improving the utilization rate of the material.

[0064] In some embodiments, during the second arc micro-explosion, the electrode is fed horizontally relative to the second mixed material at a speed of 600 mm / min and vertically at a speed of 0.5 mm / min.

[0065] In some embodiments, during the second arc micro-explosion, the second mixed material is formed into droplets, which are then cooled to obtain powder of the second mixed material using a coolant, which includes water.

[0066] In some embodiments, the coolant includes at least one of Na2CO3 aqueous solution and K2CO3 aqueous solution. In this embodiment, using at least one of Na2CO3 aqueous solution and K2CO3 aqueous solution as the coolant can instantly form an alkali-rich film on the surface of the small droplets generated in the melting pit, blocking oxygen diffusion. In the subsequent low-temperature reduction process, the volatilization of the alkali metal can also remove SiO2 from the alloy surface, reducing the oxygen content of the alloy powder without affecting the sphericity of the alloy powder.

[0067] In some embodiments, the mass concentration of the Na2CO3 aqueous solution is 20%~30%, and the mass concentration of the K2CO3 aqueous solution is 20%~30%.

[0068] In some embodiments, the second mixed material powder is washed before being processed in the subsequent step S30.

[0069] In some embodiments, the second mixture powder is washed with an alcohol-based cleaning agent, such as ethanol.

[0070] In some embodiments, in step S30, the second mixed material powder is reduced in a hydrogen atmosphere, which makes it less likely for side reactions to occur and for excessive impurities to be generated.

[0071] In some embodiments, the temperature range of the reduction process is 850°C to 950°C.

[0072] In some embodiments, the restoration process takes 3 to 4 hours.

[0073] In some embodiments, the alloy powder obtained in step S30 is further subjected to sieving.

[0074] In some embodiments, the screening process includes ultrasonic vibration screening or airflow classification screening.

[0075] In some embodiments, the particle size range of the alloy powder obtained by sieving is 50 μm to 150 μm.

[0076] The alloy powder of this invention can be used as a raw material for cladding processes, which include plasma cladding and laser cladding.

[0077] This invention also provides a cladding process method, which includes the steps of the alloy powder preparation method described above, wherein the prepared alloy powder is used as a raw material, and a cladding layer product is prepared through a cladding process. The cladding process includes laser cladding or plasma cladding, and the cladding layer product includes a clad metal coating.

[0078] The cladding process of the present invention can refer to the well-known process flow and process parameters in the art. The alloy powder of the present invention is used as the raw material in the cladding process. Because the alloy powder is a mixture of different types of metal powders in a certain weight ratio, the proportion can be customized in the preparation of the first mixed material powder according to the composition requirements of the cladding layer product. Then, the physical mixing is carried out by ball milling, the chemical mixing is carried out in the sintering process, and finally, the alloy powder with uniform composition, high sphericity, lower cost and less surface oxide is easily obtained. When the alloy powder is applied to the cladding process, material segregation is not easy to occur, and a cladding layer product with uniform composition can be prepared.

[0079] The technical solution of the present invention will be further described in detail below with reference to specific embodiments. It should be understood that the following specific embodiments are only used to explain the present invention and are not intended to limit the present invention.

[0080] Example 1

[0081] The preparation method of the alloy powder in this embodiment is as follows:

[0082] S10. Mix WC and TiC in a 1:1 mass ratio (the average sphere diameter of WC is 5μm, and the average sphere diameter of TiC is 1 / 10 of the average sphere diameter of WC). Stir evenly in a powder mixer, then ball mill thoroughly and place in a vacuum sintering furnace for a first sintering at 1200℃ for 5 hours to form a first mixed material. Connect the first mixed material to the positive electrode of a pulse power supply and the graphite electrode to the negative electrode of the pulse power supply. The relative gap between the positive and negative electrodes of the pulse power supply is 0.03mm. Apply a current of 320A between the positive and negative electrodes to cause an arc discharge on the nearest surface of the first mixed material, forming a molten pit on the surface of the first mixed material. Introduce a high-pressure pure water fluid with a pressure of 1MPa and a flow rate of 40L / min between the positive and negative electrodes of the pulse power supply. Locally enhance the high-speed flow of the fluid across the molten pit on the surface of the first mixed material, causing the molten pit to explode and generate numerous small droplets. The small droplets fly away from the molten zone and are cooled by external low-temperature water to obtain the first mixed material powder.

[0083] S20. Mix the first mixed material powder, Co powder with an average particle size of 200 μm, and Si powder with an average particle size of 150 μm in a mass ratio of 100:55:8. Stir the mixture evenly in a powder mixer, then ball-mill the mixture thoroughly. Place the mixture in a vacuum sintering furnace and sinter it a second time at 1400℃ for 6 hours to form the second mixed material. Connect the second mixed material to the positive terminal of the pulse power supply, and connect the graphite electrode to the negative terminal of the pulse power supply. The relative gap between the positive and negative terminals of the pulse power supply is 0.03 mm. A current of 320A is applied between the positive and negative electrodes, causing an arc discharge on the surface of the second mixed material, forming a molten pit on the surface of the second mixed material. A high-pressure fluid of pure water with a pressure of 1MPa and a flow rate of 50L / min is introduced between the positive and negative electrodes of the pulse power supply. The fluid is then rapidly passed over the molten pit on the surface of the second mixed material, causing the molten pit to explode and generate countless small droplets. The small droplets fly away from the molten area and are cooled by an external low-temperature Na2CO3 aqueous solution with a mass concentration of 20% to obtain the powder of the second mixed material.

[0084] S30. The second mixed material powder is cleaned with ethanol, an alcohol-based cleaning agent, and then placed in a hydrogen atmosphere for sintering and reduction at 850°C for 4 hours. Then, it is sieved in an air classifier to obtain alloy powder with a particle size range of 50μm~150μm, with a particle size less than 50μm and a particle size greater than 150μm.

[0085] Example 2

[0086] Example 2: Alloy powder was prepared using the same method as in Example 1, except that the mass ratio of WC to TiC was 1:0.5.

[0087] Example 3

[0088] Example 3 prepared alloy powder according to the preparation method of Example 1. The difference is that in Example 3, in the second arc micro-explosion, the small droplets flew away from the molten zone and were cooled by external low-temperature water to obtain the second mixed material powder.

[0089] Example 4

[0090] Example 4 prepared alloy powder according to the preparation method of Example 1. The difference is that ammonium bicarbonate was added in step S20 of Example 4. The mass ratio of the first mixed material powder and the Co, Si and ammonium bicarbonate was 100:55:8:1.

[0091] Comparative Example 1

[0092] Comparative Example 1 prepared alloy powder according to the preparation method of Example 1, except that TiC was not added.

[0093] Comparative Example 2

[0094] Comparative Example 2 is composed of the same components as in Example 1. However, in Comparative Example 2, the various raw material components are mixed evenly by stirring. Then, a second mixed material powder is prepared according to step S20, and then alloy powder is obtained by the subsequent step S30.

[0095] Performance testing

[0096] 1. The sphericity of the alloy powders in the examples and comparative examples was determined and recorded in Table 1.

[0097] 2. The oxygen content of the alloy powders in the examples and comparative examples was determined and recorded in Table 1.

[0098] 3. Using alloy powder with a particle size of 50μm~150μm obtained from the examples and comparative examples as raw materials, and FV520B steel plate as substrate, a cladding alloy coating with a thickness of 5nm was prepared on the surface of the steel plate by plasma cladding process. The process parameters of plasma cladding are as follows: argon gas with a purity of 99.99% is used as protective gas, the current is set to 100A, the voltage is set to 50V, and the feed rate is 5.5g / min.

[0099] The obtained cladding alloy coating was subjected to thermal shock testing. Specifically, the substrate containing the cladding alloy coating was placed in a furnace and heated to 500°C for 10 minutes, and then placed in cold water at -20°C for 10 minutes. This was used as one test cycle, and the cycle was repeated 150 times. The presence of fine cracks or crazing in the cladding alloy coating was observed and recorded in Table 1.

[0100] 4. The hardness of the cladding alloy coatings prepared from the alloy powders of the examples and comparative examples was measured and recorded in Table 1.

[0101] Table 1

[0102]

[0103] As shown in Table 1, the alloy powder prepared by the method of the embodiment has a high sphericity and an oxygen content of less than 500 mmp. Moreover, the components in the alloy powder are mixed relatively uniformly. Using the alloy powder of the embodiment as raw material, the various materials in the alloy powder are mixed uniformly. The clad alloy coating prepared by the plasma cladding process has good uniformity and good adhesion to the substrate. After thermal shock testing, the clad alloy coating is intact and free of micro-cracks and cracks.

[0104] Comparative Example 1 used only WC as a single hard phase without adding TiC. It had good high-temperature resistance, but its hardness performance was not outstanding.

[0105] Comparative Example 2 uses alloy powder obtained by physically mixing alloy materials and additives as raw material. However, physical mixing methods are difficult to achieve uniform mixing, and problems such as material segregation easily occur during the preparation of the cladding alloy coating. This leads to unevenness in the prepared cladding alloy coating, thus affecting its durability. Consequently, the cladding alloy coating exhibited numerous fine cracks after thermal shock testing. Its high-temperature resistance and hardness performance are also unsatisfactory.

[0106] The above are merely preferred embodiments of the present invention and do not limit the scope of the patent. Any equivalent structural or procedural transformations made based on the description and drawings of the present invention, or direct or indirect applications in other related technical fields, are similarly included within the scope of patent protection of the present invention.

Claims

1. A method for preparing alloy powder, characterized in that, Includes the following steps: S10. Mix WC and TiC, perform a first mixing ball milling and a first sintering to obtain a first mixed material, and perform a first electric arc micro-explosion on the first mixed material to obtain the first mixed material powder. S20. The first mixed material powder, Co, and Si are mixed, and then subjected to a second mixing ball milling and a second sintering to obtain a second mixed material. The second mixed material is then subjected to a second electric arc micro-explosion to obtain a second mixed material powder. S30. The second mixed material powder is subjected to reduction treatment to obtain alloy powder.

2. The method for preparing the alloy powder according to claim 1, characterized in that, The mass ratio of WC to TiC is (1:0.1) to (1:1).

3. The method for preparing the alloy powder according to claim 1, characterized in that, The average sphere diameter of WC is 0.1 μm to 10 μm, while the average sphere diameter of TiC is 1 / 10 of that of WC.

4. The method for preparing the alloy powder according to claim 1, characterized in that, The mass ratio of the first mixed material powder to Co and Si is 100:(40~60):(4~10).

5. The method for preparing the alloy powder according to claim 1, characterized in that, The temperature of the first sintering is 1200℃~1300℃, and the time of the first sintering is 4h~5h.

6. The method for preparing the alloy powder according to claim 1, characterized in that, The temperature of the second sintering is 1400℃~1500℃; the time of the second sintering is 6h~10h.

7. The method for preparing alloy powder according to claim 1, characterized in that, The reduction treatment is performed at a temperature of 850℃ to 950℃ for 3 to 4 hours.

8. The method for preparing the alloy powder according to claim 1, characterized in that, In step S20, the first mixed material powder, Co, Si and ammonium bicarbonate are mixed, and then the second mixing ball milling is performed.

9. The method for preparing the alloy powder according to claim 1, characterized in that, During the second arc micro-explosion, the second mixture is formed into droplets, which are then cooled to obtain powder of the second mixture. The cooling includes a coolant, which includes at least one of Na2CO3 aqueous solution and K2CO3 aqueous solution.

10. An alloy powder prepared by any one of the alloy powders described in claims 1 to 9.

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