A dual-phase particle reinforced nickel-based composite coating layer with high-temperature resistant friction realized by component preferential oxidation and a preparation method thereof

Abstract

The present application relates to a kind of by component priority oxidation maintains high wear resistance at high temperature two-phase particle reinforced nickel-based composite coating and its preparation process.The present application provides a kind of by regulation material phase composition, by W2C phase high-temperature priority oxidation process, the interface stability between nickel-based adhesive phase and reinforcing particle at 800 DEG C is maintained, oxidation debonding and hard phase particle pull-out are avoided.The obtained coating has the advantages of high hard phase content, 800 DEG C maintains high wear resistance.The preparation process of coating mainly includes powder mixing, substrate pretreatment, plasma transferred arc surfacing and postweld treatment.There is no crack in the coating, and the hard phase particles are uniformly distributed in the coating;The relative wear resistance of the prepared coating at 800 DEG C is 16.7~18.6, and the high-temperature hardness is maintained at 764~813 HV, with high-temperature softening and wear resistance characteristics.

Description

Technical Field

[0001] This invention belongs to the field of composite coatings and relates to a biphase particle-reinforced nickel-based composite coating and its preparation method that utilizes the preferential oxidation process of W2C to maintain the stability of the interface between the binder phase and the hard phase particles at 800 °C, avoiding interface debonding and particle pull-out. Technical Background

[0002] Nickel-based tungsten carbide composite coatings are widely used in high-wear scenarios due to their comprehensive properties, including high wear resistance, high hardness, and good oxidation resistance. Currently, high-temperature friction and wear caused by heat or continuous coupling and contact place stringent requirements on the high-temperature wear resistance of this material system. However, on the one hand, when the temperature exceeds 500 °C, low-hardness, highly brittle oxides such as WO3 easily form on the surface of tungsten carbide particles, leading to debonding and particle pull-out behavior at the nickel-based binder phase / tungsten carbide particle interface at high temperatures. On the other hand, to improve the wear resistance of nickel-based tungsten carbide composite coatings, coarse-grained tungsten carbide is often used, which further exacerbates the nickel-based binder phase / tungsten carbide particle interface problem at high temperatures. These issues lead to a decrease in the wear resistance of nickel-based tungsten carbide coatings at high temperatures, severely limiting the expanded application of this material in high-temperature environments. Increasingly challenging working environments require composite coatings to maintain good performance under even more extreme temperature conditions. Therefore, it is necessary to consider how to achieve the stability of the nickel-based binder phase / tungsten carbide particle interface at high temperatures and prevent particle pull-out in order to maintain the high wear resistance of the system through interface engineering.

[0003] The W2C phase is more reactive than the WC phase and the Ni-based matrix phase at high temperatures. It can preferentially react with O2 to form WO compounds, thereby slowing down the oxidation of the WC and Ni-based bonding phases. This transforms the interfacial failure caused by adding only the WC single phase into a controllable oxidation loss, thus avoiding interfacial debonding and particle pull-out during subsequent high-temperature friction. This allows the hard phase particles to play their due wear-resistant role, achieving high wear resistance of the composite coating at high temperatures. Summary of the Invention

[0004] This invention aims to provide a biphase particle-reinforced nickel-based composite coating with high-temperature friction resistance achieved through preferential oxidation of components, and its preparation method. This invention utilizes the preferential oxidation of the W2C phase over the WC and binder phases at high temperatures, protecting the binder phase / hard particle interface and avoiding interfacial oxidation debonding and particle pull-out during friction. This allows the prepared biphase particle-reinforced nickel-based composite coating to maintain high hardness and high wear resistance even at 800 °C, and the preparation process of this composite coating is simple.

[0005] The raw material ratio for the dual-phase particle-reinforced nickel-based composite coating with preferential oxidation of the components to achieve high-temperature friction resistance is as follows: the hard phase is W2C / WC dual-phase particles, prepared by casting-crushing method, with a particle size range of 89~166 μm and a mass percentage of 58.7%~64.8% based on the total coating mass; the W2C:WC ratio in the particles ranges from 0.21:1 to 3.03:1. The binder phase used is nickel-based alloy powder, with a mass percentage of 32.0%~38.5% based on the total coating mass. This alloy powder is prepared by vacuum atomization powder preparation, and its elemental mass percentages are: Ni: 69.25%~73.08%, Cr: 15.60%~16.50%, Si: 3.00%~3.70%, B: 2.90%~3.60%, Fe: 4.00%~6.90%, C: The content of Cu / Mo powder is 0.62%~0.70%, and the particle size range is 75~148 μm. In addition, Cu / Mo powder is added as a flux, with a Cu:Mo mass ratio of 2:3~3:2 and a particle size range of 48~76 μm. The mass percentage of Cu / Mo powder is 2.80%~3.20% based on the total mass of the coating.

[0006] After weighing the required powder raw materials, the nickel-based alloy powder and Cu / Mo powder are first uniformly mixed to obtain a binder phase powder; then, the binder phase powder is uniformly mixed with W2C / WC dual-phase particles. A dual-phase particle-reinforced nickel-based composite coating is prepared using a plasma transfer arc welding process, which features simple operation, the ability to add coarse WC particles, and controllable WC particle dissolution. The prepared coating is crack-free, has few defects, and exhibits uniform distribution and low dissolution of the hard phase particles.

[0007] When the coating is subjected to friction and wear at 800 °C, it exhibits preferential oxidation of the W2C phase, which limits the oxidation of the WC phase and the nickel-based binder phase, maintains the stability of the binder phase / particle interface, and allows the hard phase particles to be well held and exert their due wear resistance. If the wear resistance of 42CrMo at 800 °C is defined as 1, then the relative wear resistance of the dual-phase particle-reinforced nickel-based composite coating is 16.7~18.6, and it maintains a high-temperature hardness of 764~813 HV. It has preferential oxidation characteristics and high-temperature friction and softening properties.

[0008] In nickel-based coatings reinforced with WC unidirectional particles, the oxidation process of WC particles during high-temperature friction weakens the bonding between the binder phase and the particle interface. Furthermore, the high-temperature softening and oxidation loss of the nickel-based binder phase, along with repeated cutting of the mating materials, further exacerbates the damage to the interface. Consequently, at high temperatures, the WC particles are pulled out entirely and become trapped between the coating and the mating materials, intensifying wear. Therefore, the wear resistance of the WC particles and the wear resistance of the coating cannot be fully realized at high temperatures.

[0009] The method for preparing a high-temperature friction-resistant dual-phase particle-reinforced nickel-based composite coating by preferential oxidation of components with the above properties includes the following steps:

[0010] Step (1): Preparation of powder raw materials:

[0011] Taking the preparation of 2 kg of biphase particle / nickel-based binder phase mixed powder as an example:

[0012] Preparation of binder phase powder: Take 640~770 g of nickel-based alloy powder with the following elemental mass percentages: Ni: 69.25%~73.08%, Cr: 15.60%~16.50%, Si: 3.00%~3.70%, B: 2.90%~3.60%, Fe: 4.00%~6.90%, C: 0.62%~0.70%, and a particle size range of 75~148 μm; take 56~64 g of Cu / Mo flux powder with a Cu:Mo ratio of 2:3~3:2 and a particle size range of 48~76 μm; mix the two powders using a planetary ball mill or a V-type mixing drum to obtain a uniformly mixed binder phase powder with good flowability; during planetary ball milling, no milling media are added, the rotation speed is set to 150~180 r / min, and the mixture is mixed at an inclination angle of 38~46° for 8~10 minutes. h; When mixing with a V-shaped mixing drum, set the rotation speed to 50~60 r / min and the mixing time to 12~14 h;

[0013] Mixing of biphase particles / nickel-based binder phase powder: Take 1174~1296 g of binder phase powder and hard phase powder with W2C / WC biphase, and mix them using a V-shaped drum or roller. The rotation speed of the roller mixer and V-shaped mixer is set to 30~45 r / min, and the mixing time is 16~20 h. A dry, uniformly mixed biphase particle / nickel-based binder phase mixed powder with good flowability and no obvious W2C / WC biphase particle specific gravity segregation is obtained.

[0014] Step (2): Pretreatment of substrate material:

[0015] The substrates used include carbon steel and structural steel. After cleaning the substrate surface by sandblasting, shot peening, grinding with a grinding wheel or steel wool, the substrate surface is cleaned with ethanol or propanol. The substrate is then preheated at 320~400 ℃ for 3~5 hours. The preheating equipment includes tube furnace, box furnace and muffle furnace.

[0016] Step (3): Plasma transfer arc welding:

[0017] The powder mixture is filled into the powder feeding device of the plasma transfer arc welding system, using argon or nitrogen as the powder feeding and shielding gas; a plasma transfer arc welding coating is prepared on the substrate surface;

[0018] During plasma transfer arc welding, the welding current is set to 95~105 A, the welding speed is set to 45~60 mm / min, and the powder feed rate is 20~25 g / min; the distance between the welding torch and the substrate is 10~12 mm, the oscillation amplitude is 10~12 mm, and the oscillation speed is 1600~1800 mm / min; the ion gas flow rate is 2~3 L / min, and the shielding gas flow rate is 12~15 L / min.

[0019] Step (4): Post-weld treatment of coating:

[0020] After plasma transfer arc welding, the coating is transferred to a heat treatment device and held at 250~300 ℃ for 4~6 h, followed by furnace cooling or air cooling. The heat treatment device includes muffle furnace, box furnace and salt bath furnace; or asbestos mesh is used for slow cooling; or air cooling is performed directly; after cooling, a dual-phase particle-reinforced nickel-based composite coating with preferential oxidation of components to achieve high-temperature friction resistance is obtained.

[0021] The wear resistance of the prepared coating at 800 °C was evaluated by reciprocating friction and wear, and the relative wear resistance of the prepared coating was calculated using the wear rate of 42CrMo as a baseline.

[0022] The preparation process of the coating described above is relatively simple. By introducing an additional W2C phase, a W2C / WC dual-phase particle reinforcement characteristic is formed. Due to its active chemical properties, W2C preferentially oxidizes over WC and the binder phase. Compared with existing nickel-based tungsten carbide coatings, the dual-phase particle-reinforced nickel-based coating provided by this invention has the following advantages:

[0023] (1) In this dual-phase particle-reinforced nickel-based composite coating, while adding high content of coarse particle reinforcing phase particles, the coating quality is high and there is no cracking behavior.

[0024] (2) In this dual-phase particle-reinforced nickel-based composite coating, the hard phase particles are retained in a high amount and can be evenly distributed in all areas of the coating, providing excellent microstructure characteristics for the high wear resistance of the coating.

[0025] (3) In the biphase particle-reinforced nickel-based composite coating, during the high-temperature friction process at 800 ℃, the W2C phase has preferential oxidation characteristics and is oxidized preferentially over the WC phase and nickel-based adhesive phase, which limits the oxidation of the WC phase and nickel-based adhesive phase, inhibits the oxidation and debonding of the adhesive phase / particle interface, and plays an interface buffer protection role at high temperature.

[0026] (4) During the high-temperature friction process at 800 ℃, the interface protection induced by W2C in the dual-phase particle-reinforced nickel-based composite coating ensures that the hard phase particles are well held, avoiding failure caused by particle pull-out. The particle retention rate is high after high-temperature friction. If the wear resistance of 42CrMo steel at 800 ℃ is defined as 1, the relative wear resistance of the dual-phase particle-reinforced nickel-based composite coating prepared by this invention reaches 16.7~18.6, and maintains a high-temperature hardness of 764~813 HV, which has the characteristic of resisting high-temperature friction at 800 ℃.

[0027] (5) The biphase particle-reinforced nickel-based composite coating produced by the present invention has the advantages of simple preparation process, simple equipment, strong operability and low preparation cost. Attached Figure Description

[0028] Figure 1 Example 1: Scanning electron microscope image of the cross-section of a biphase particle-reinforced nickel-based composite coating;

[0029] Figure 2 Friction coefficient curves at 800 °C for the preparation of a dual-phase particle-reinforced nickel-based composite coating in Example 1 and the comparative example of Example 1;

[0030] Figure 3 Scanning electron microscope (SEM) images and three-dimensional contour images of the biphase particle-reinforced nickel-based sample prepared in Example 1 and the comparative example of Example 1 after being rubbed at 800 °C. Detailed Implementation

[0031] Example 1

[0032] 1. Powder Mixing: Weigh out 37.0% nickel-based alloy powder, 3.0% Cu / Mo flux powder, and 60.0% W2C / WC duplex particles according to the following mass ratio: Nickel-based alloy powder composition: Ni: 73.08%, Cr: 15.60%, Si: 3.20%, B: 3.40%, Fe: 4.10%, C: 0.62%, with a particle size range of 75~148 μm and an average particle size of 109 μm; Cu / Mo flux powder has a Cu:Mo ratio of 3:2, a particle size range of 56~76 μm, and an average particle size of 63 μm; W2C / WC particles have a W2C:WC ratio of 3.03:1, a particle size range of 110~162 μm, and an average particle size of 131 μm. First, place the nickel-based alloy powder and Cu / Mo flux powder into a ball mill jar and mill at 150°C. Mixing was carried out at a rotation speed of r / min and an inclination angle of 38° for 10 h without the addition of ball milling media; a nickel-based binder phase powder with certain fluidity and uniform mixing was obtained.

[0033] The nickel-based binder phase powder and W2C / WC biphase particles were placed together in a V-shaped feed cylinder and mixed at a speed of 45 r / min for 16 h to obtain a dry, uniformly mixed, and free-flowing biphase particle / nickel-based binder phase mixed powder with no obvious W2C / WC biphase particle specific gravity segregation.

[0034] 2. Substrate pretreatment: The 42CrMo substrate was treated with a sandblasting machine to remove the oxide film on the surface; then, propanol was used to remove oil residue and sand; the substrate was placed in a muffle furnace and preheated at 320 ℃ for 5 h.

[0035] 3. Plasma transfer arc welding: The powder mixture is filled into the powder feeding device, and the preheated 42CrMo substrate material is transferred to the working area. The powder is fed and protected by argon gas. The coating is prepared by plasma transfer arc welding: the welding current is set to 95 A, the welding speed is set to 45 mm / min, and the powder feeding rate is 21 g / min; the distance between the welding torch and the substrate is 10 mm, the oscillation amplitude is 11 mm, and the oscillation speed is 1800 mm / min; the ion gas flow rate is 2.5 L / min, and the shielding gas flow rate is 12 L / min.

[0036] 4. Post-weld treatment of coating: After welding, the prepared coating is transferred to a box furnace and held at 250 ℃ for 6 h, and then cooled with the furnace; a nickel-based composite coating reinforced with W2C / WC dual-phase particles is obtained.

[0037] The biphase particle-reinforced nickel-based composite coating prepared by the above method is free of cracks and obvious defects. Figure 1 The cross-sectional scanning electron microscope image of the coating shows that in this dual-phase particle-reinforced nickel-based composite coating, the hard phase particles retain large particle size, high retention amount, and are uniformly distributed in all regions of the coating. This coating maintains a high-temperature hardness of 813 HV at 800 °C, while the comparative high-temperature hardness is only 447 HV; after reciprocating friction and wear at 800 °C, Figure 2 The friction coefficient curves of the coating and the comparative example show that the friction process stability of the coating is better than that of the comparative example with only WC single-phase particles added, and the curve has less fluctuation and dispersion. Figure 3The scanning electron microscope (SEM) images and 3D contour images of the coating and the comparative example after oxidation and wear show that the W2C phase introduced by the biphase particles, through a preferential oxidation process, restricts the oxidation of the WC phase and the matrix phase, as well as the softening process of the matrix, thus maintaining the stability of the bonding phase / particle interface. This prevents severe pull-out behavior of the hard phase particles during friction and wear, resulting in a W2C / WC biphase particle retention rate of 51.6%, while the retention rate of the WC single-phase particles in the comparative example is only 24.6%. Based on the volumetric wear rate calculation, if the wear resistance of 42CrMo at 800 °C is defined as 1, the relative wear resistance of the comparative example is only 4.7, while the relative wear resistance of this biphase particle-reinforced nickel-based composite coating reaches 17.9, exhibiting preferential oxidation characteristics and high-temperature friction resistance.

[0038] Comparative Example 1: WC single-phase particle powder was used as the hard particle, and its particle size range and average particle size were similar to those of the W2C / WC dual-phase particles in Example 1 of this invention. After being mixed with nickel-based binder powder, plasma welding was performed. The process parameters were the same as in Example 1, and the specific preparation steps are as follows:

[0039] 1. Powder Mixing: Weigh out 37.0% nickel-based alloy powder, 3.0% Cu / Mo flux powder, and 60.0% WC particles by mass ratio. The nickel-based alloy powder composition is as follows: Ni: 73.08%, Cr: 15.60%, Si: 3.20%, B: 3.40%, Fe: 4.10%, C: 0.62%, with a particle size range of 75–148 μm and an average particle size of 109 μm. The Cu / Mo flux powder has a Cu:Mo ratio of 3:2, a particle size range of 56–76 μm, and an average particle size of 63 μm. The WC particles have a particle size range of 112–158 μm and an average particle size of 128 μm. First, place the nickel-based alloy powder and Cu / Mo flux powder into a ball mill jar and mill at 150 r / min and a 38° inclination angle for 10 minutes without adding milling media. h mixing; to obtain a nickel-based binder phase powder with certain fluidity and uniform mixing;

[0040] Nickel-based binder powder and WC particles were placed together in a V-shaped barrel and mixed at a speed of 45 r / min for 16 h to obtain a dry, uniformly mixed powder with good flowability and no obvious WC particle specific gravity segregation.

[0041] 2. Substrate pretreatment: The 42CrMo substrate was treated with a sandblasting machine to remove the oxide film on the surface; then, propanol was used to remove oil residue and sand; the substrate was placed in a muffle furnace and preheated at 320 ℃ for 5 h.

[0042] 3. Plasma transfer arc welding: The powder mixture is filled into the powder feeding device, and the preheated 42CrMo substrate material is transferred to the working area. The powder is fed and protected by argon gas. The coating is prepared by plasma transfer arc welding: the welding current is set to 95 A, the welding speed is set to 45 mm / min, and the powder feeding rate is 21 g / min; the distance between the welding torch and the substrate is 10 mm, the oscillation amplitude is 11 mm, and the oscillation speed is 1800 mm / min; the ion gas flow rate is 2.5 L / min, and the shielding gas flow rate is 12 L / min.

[0043] 4. Post-weld treatment of coating: After welding, the prepared coating is transferred to a box furnace and kept at 250 ℃ for 6 h, and then cooled with the furnace; a nickel-based composite coating reinforced with WC particles is obtained.

[0044] The WC particle-reinforced nickel-based composite coating prepared by the above method is free of crack defects. The hard phase particles retain large particle size, high retention amount, and are uniformly distributed in all areas of the coating. This coating softens significantly at 800 °C, retaining only a high-temperature hardness of 447 HV; after reciprocating friction wear at 800 °C, Figure 2 The friction coefficient curves of this coating and the comparative example show that the friction process stability of this coating is worse than that of Example 1. Figure 3 To compare the surface scanning electron microscope (SEM) images and 3D contour images after oxidation and wear, it is shown that the addition of WC single-phase particles cannot prevent the pull-out behavior of hard phase particles during the high-temperature friction and wear process at 800 °C. This results in a WC single-phase particle retention rate of only 24.6%, far lower than the particle retention rate of the biphase particle-reinforced nickel-based composite coating prepared in Example 1. Based on the volumetric wear rate calculation, if the wear resistance of 42CrMo at 800 °C is defined as 1, the relative wear resistance of this comparative example is only 4.7, significantly lower than the relative wear resistance of the biphase particle-reinforced nickel-based composite coating prepared in Example 1.

[0045] Example 2

[0046] 1. Powder Mixing: Weigh out 34.3% nickel-based alloy powder, 3.1% Cu / Mo flux powder, and 62.6% W2C / WC duplex particles according to the following mass ratio: Nickel-based alloy powder composition: Ni: 70.80%, Cr: 16.50%, Si: 3.20%, B: 3.00%, Fe: 5.80%, C: 0.70%, with a particle size range of 82~136 μm and an average particle size of 118 μm; Cu / Mo flux powder has a Cu:Mo ratio of 1:1, a particle size range of 48~66 μm, and an average particle size of 58 μm; W2C / WC particles have a W2C:WC ratio of 1.95:1, a particle size range of 96~132 μm, and an average particle size of 112 μm. First, place the nickel-based alloy powder and Cu / Mo flux powder into a V-shaped feeder, and then mix at 60°C. The mixture was stirred at a speed of r / min for 12 h to obtain a nickel-based binder powder with certain fluidity and uniform mixing.

[0047] Nickel-based binder phase powder and W2C / WC biphase particles were placed together in a drum and mixed at a speed of 30 r / min for 20 h to obtain a dry, uniformly mixed biphase particle / nickel-based binder phase powder with good flowability and no obvious W2C / WC biphase particle specific gravity segregation.

[0048] 2. Pretreatment of the substrate: The H13 substrate was treated with a grinding wheel to remove the oxide film on the surface; then the oil residue was removed with ethanol; the substrate was placed in a box furnace and preheated at 350 °C for 4 h.

[0049] 3. Plasma transfer arc welding: The powder mixture is filled into the powder feeding device, and the preheated H13 substrate material is transferred to the working area. Nitrogen gas is used for powder feeding and protection. The coating is prepared by plasma transfer arc welding: the welding current is set to 100 A, the welding speed is set to 55 mm / min, and the powder feeding rate is 24 g / min; the distance between the welding torch and the substrate is 11 mm, the oscillation amplitude is 10 mm, and the oscillation speed is 1600 mm / min; the ion gas flow rate is 3 L / min, and the shielding gas flow rate is 13 L / min.

[0050] 4. Post-weld treatment of coating: After welding, the prepared coating is wrapped with asbestos mesh for slow cooling; a nickel-based composite coating reinforced with W2C / WC dual-phase particles is obtained.

[0051] The biphase particle-reinforced nickel-based composite coating prepared by the above method is free of crack defects. The hard phase particles retain large particle size, high retention amount, and are uniformly distributed in all areas of the coating. This coating maintains a high-temperature hardness of 805 HV at 800 ℃. After reciprocating friction and wear at 800 ℃, although the proportion of the W2C phase in the coating decreases, it still exhibits preferential oxidation, protecting the stability of the binder phase / particle interface and preventing pull-out of hard phase particles during friction and wear. The retention rate of W2C / WC biphase particles is 49.7%. Based on volumetric wear rate calculations, if the wear resistance of 42CrMo at 800 ℃ is defined as 1, the relative wear resistance of this biphase particle-reinforced nickel-based composite coating reaches 18.6, demonstrating preferential oxidation characteristics and high-temperature friction resistance.

[0052] Example 3

[0053] 1. Powder Mixing: Weigh out 32.0% nickel-based alloy powder, 3.2% Cu / Mo flux powder, and 64.8% W2C / WC duplex particles according to the following mass ratio: Nickel-based alloy powder composition: Ni: 70.40%, Cr: 16.30%, Si: 3.40%, B: 2.90%, Fe: 6.40%, C: 0.60%, with a particle size range of 98~142 μm and an average particle size of 114 μm; Cu / Mo flux powder has a Cu:Mo ratio of 1:1, a particle size range of 51~72 μm, and an average particle size of 61 μm; W2C / WC particles have a W2C:WC ratio of 1.08:1, a particle size range of 103~166 μm, and an average particle size of 121 μm. First, place the nickel-based alloy powder and Cu / Mo flux powder into a ball mill jar and mill at 180°C. Mixing was carried out at a rotation speed of r / min and an inclination angle of 46° for 8 hours without the addition of ball milling media; a nickel-based binder phase powder with certain fluidity and uniform mixing was obtained.

[0054] The nickel-based binder phase powder and W2C / WC biphase particles were placed together in a V-shaped feed cylinder and mixed at a speed of 35 r / min for 18 h to obtain a dry, uniformly mixed, and free-flowing biphase particle / nickel-based binder phase mixed powder with no obvious W2C / WC biphase particle specific gravity segregation.

[0055] 2. Substrate pretreatment: The M2 substrate is treated with a sandblasting machine to remove the oxide film on the surface; then, ethanol is used to remove oil residue and sand; the substrate is placed in a tube furnace and preheated at 380 ℃ for 3 h.

[0056] 3. Plasma transfer arc welding: The powder mixture is filled into the powder feeding device, and the preheated M2 substrate material is transferred to the working area. The powder is fed and protected by argon gas. The coating is prepared by plasma transfer arc welding: the welding current is set to 105 A, the welding speed is set to 60 mm / min, and the powder feeding rate is 25 g / min; the distance between the welding torch and the substrate is 10 mm, the oscillation amplitude is 12 mm, and the oscillation speed is 1650 mm / min; the ion gas flow rate is 2.8 L / min, and the shielding gas flow rate is 15 L / min.

[0057] 4. Post-weld treatment of coating: After welding, the prepared coating is transferred to a muffle furnace and held at 280 ℃ for 4 h, and then cooled with the furnace; a nickel-based composite coating reinforced with W2C / WC dual-phase particles is obtained.

[0058] The biphase particle-reinforced nickel-based composite coating prepared by the above method is free of cracks and obvious defects. The hard phase particles retain a large particle size and high retention rate, with intact morphology and uniform distribution in all areas of the coating. This coating maintains a high-temperature hardness of 801 HV at 800 ℃. Under reciprocating friction and wear at 800 ℃, the W2C phase in the coating exhibits its preferential oxidation effect, limiting the oxidation degree of the WC phase and the matrix phase, protecting the stability of the binder phase / particle interface, and preventing the pull-out behavior of hard phase particles during friction and wear, resulting in a W2C / WC biphase particle retention rate of 50.9%. Based on volumetric wear rate calculations, if the wear resistance of 42CrMo at 800 ℃ is defined as 1, the relative wear resistance of this biphase particle-reinforced nickel-based composite coating reaches 17.7, demonstrating preferential oxidation characteristics and high-temperature friction resistance.

[0059] Example 4

[0060] 1. Powder Mixing: Weigh out 35.9% nickel-based alloy powder, 2.9% Cu / Mo flux powder, and 61.2% W2C / WC duplex particles according to the following mass ratio: Nickel-based alloy powder composition: Ni: 69.25%, Cr: 15.90%, Si: 3.70%, B: 3.60%, Fe: 6.90%, C: 0.65%, with a particle size range of 80~139 μm and an average particle size of 97 μm; Cu / Mo flux powder has a Cu:Mo ratio of 2:3, a particle size range of 48~76 μm, and an average particle size of 66 μm; W2C / WC particles have a W2C:WC ratio of 0.55:1, a particle size range of 89~162 μm, and an average particle size of 126 μm. First, place the nickel-based alloy powder and Cu / Mo flux powder into a V-shaped feeder, and then mix at 50°C. Mix at a rotation speed of r / min for 14 h to obtain a nickel-based binder phase powder with certain fluidity and uniform mixing.

[0061] Nickel-based binder phase powder and W2C / WC biphase particles were placed together in a drum and mixed at a speed of 35 r / min for 18 h to obtain a dry, uniformly mixed biphase particle / nickel-based binder phase powder with good flowability and no obvious W2C / WC biphase particle specific gravity segregation.

[0062] 2. Pretreatment of the substrate: Use steel wool to polish the 42CrMo substrate to remove the oxide film on the surface; then use propanol to remove the oil residue; put the substrate into a box furnace and preheat it at 400 ℃ for 3 h.

[0063] 3. Plasma transfer arc welding: The powder mixture is filled into the powder feeding device, and the preheated 42CrMo substrate material is transferred to the working area. Nitrogen gas is used for powder feeding and protection. The coating is prepared by plasma transfer arc welding: the welding current is set to 97 A, the welding speed is set to 50 mm / min, and the powder feeding rate is 22 g / min; the distance between the welding torch and the substrate is 12 mm, the oscillation amplitude is 10 mm, and the oscillation speed is 1700 mm / min; the ion gas flow rate is 2.3 L / min, and the shielding gas flow rate is 12 L / min.

[0064] 4. Post-weld treatment of coating: After welding, the prepared coating is transferred to a salt bath furnace and kept at 300 ℃ for 5 h, and then taken out and air-cooled; a nickel-based composite coating reinforced with W2C / WC dual-phase particles is obtained.

[0065] The biphase particle-reinforced nickel-based composite coating prepared by the above method is free of cracks and defects. The hard phase particles retain large particle size and high retention rate, exhibiting intact morphology and uniform distribution throughout the coating. This coating maintains a high-temperature hardness of 797 HV at 800 °C. After reciprocating friction and wear at 800 °C, although the proportion of the W2C phase in the coating is relatively low, the W2C phase still exerts its preferential oxidation effect, protecting the stability of the binder phase / particle interface and preventing the pull-out of hard phase particles during friction and wear. This results in a W2C / WC biphase particle retention rate of 47.3%. Based on volumetric wear rate calculations, if the wear resistance of 42CrMo at 800 °C is defined as 1, the relative wear resistance of this biphase particle-reinforced nickel-based composite coating reaches 17.1, demonstrating preferential oxidation characteristics and high-temperature friction resistance.

[0066] Example 5

[0067] 1. Powder Mixing: Weigh out 38.5% nickel-based alloy powder, 2.8% Cu / Mo flux powder, and 58.7% W2C / WC duplex particles according to the following mass ratio: Nickel-based alloy powder composition: Ni: 72.87%, Cr: 16.00%, Si: 3.00%, B: 3.50%, Fe: 4.00%, C: 0.63%, with a particle size range of 76~146 μm and an average particle size of 104 μm; Cu / Mo flux powder has a Cu:Mo ratio of 8:7, a particle size range of 50~69 μm, and an average particle size of 57 μm; W2C / WC particles have a W2C:WC ratio of 0.21:1, a particle size range of 106~153 μm, and an average particle size of 128 μm. First, place the nickel-based alloy powder and Cu / Mo flux powder into a ball mill jar and mill at 170°C. Mixing was carried out at a rotation speed of r / min and an inclination angle of 40° for 9 hours without the addition of ball milling media; a nickel-based binder phase powder with certain fluidity and uniform mixing was obtained.

[0068] Nickel-based binder phase powder and W2C / WC biphase particles were placed together in a drum and mixed for 16 h at a speed of 40 r / min to obtain a dry, uniformly mixed biphase particle / nickel-based binder phase powder with good flowability and no obvious W2C / WC biphase particle specific gravity segregation.

[0069] 2. Pretreatment of the substrate: The Q255 substrate is treated with a shot peening machine to remove the oxide film on the surface; then the oil residue is removed with ethanol; the substrate is placed in a muffle furnace and preheated at 360 ℃ for 5 h.

[0070] 3. Plasma transfer arc welding: The powder mixture is filled into the powder feeding device, and the preheated Q255 substrate material is transferred to the working area. The powder is fed and protected by argon gas. The coating is prepared by plasma transfer arc welding: the welding current is set to 102 A, the welding speed is set to 48 mm / min, and the powder feeding rate is 20 g / min; the distance between the welding torch and the substrate is 11 mm, the oscillation amplitude is 10 mm, and the oscillation speed is 1750 mm / min; the ion gas flow rate is 2.0 L / min, and the shielding gas flow rate is 14 L / min.

[0071] 4. Post-weld treatment of coating: After welding, air cooling is performed directly to obtain a nickel-based composite coating reinforced with W2C / WC dual-phase particles.

[0072] The biphase particle-reinforced nickel-based composite coating prepared by the above method is free of cracks and defects. The hard phase particles retain large particle size and high retention rate, exhibiting intact morphology and uniform distribution throughout the coating. This coating maintains a high-temperature hardness of 764 HV at 800 °C. Under reciprocating friction and wear at 800 °C, the W2C phase in the coating exhibits preferential oxidation, protecting the stability of the binder phase / particle interface and preventing pull-out of hard phase particles during friction and wear, resulting in a W2C / WC biphase particle retention rate of 45.2%. Based on volumetric wear rate calculations, if the wear resistance of 42CrMo at 800 °C is defined as 1, the relative wear resistance of this biphase particle-reinforced nickel-based composite coating reaches 16.7, demonstrating preferential oxidation characteristics and high-temperature friction resistance.

Claims

1. This invention aims to provide a dual-phase particle-reinforced nickel-based composite coating that achieves high-temperature friction resistance through preferential oxidation of components, characterized in that: The hard phase consists of W2C / WC dual-phase particles, prepared by a casting-crushing method. The particle size ranges from 89 to 166 μm, and its mass percentage (based on the total coating mass) is 58.7% to 64.8%. The W2C:WC ratio in the particles ranges from 0.21:1 to 3.03:

1. The binder phase is a nickel-based alloy powder, with a mass percentage (based on the total coating mass) of 32.0% to 38.5%. This alloy powder is prepared by vacuum atomization, and its elemental mass percentages are: Ni: 69.25% to 73.08%, Cr: 15.60% to 16.50%, Si: 3.00% to 3.70%, B: 2.90% to 3.60%, Fe: 4.00% to 6.90%, C: 0.62% to 0.70%, with a particle size range of 75 to 148 μm. Additionally, Cu / Mo powder is added as a flux. The mass ratio of Mo is 2:3 to 3:2, and the particle size range is 48 to 76 μm. Based on the total mass of the coating, its mass percentage is 2.80% to 3.20%. After weighing the required powder raw materials, the nickel-based alloy powder and Cu / Mo powder are first uniformly mixed to obtain the binder phase powder. Then, the binder phase powder is uniformly mixed with W2C / WC dual-phase particles. A dual-phase particle-reinforced nickel-based composite coating is prepared using plasma transfer arc welding. The prepared coating is crack-free, has few defects, and the hard phase particles are uniformly distributed with low solubility. When the coating undergoes friction and wear at 800 °C, it exhibits preferential oxidation of the W2C phase, limiting the oxidation of the WC phase and the nickel-based binder phase, maintaining the stability of the binder phase / particle interface, and allowing the hard phase particles to be well held and exert their due wear resistance. If 42CrMo is subjected to friction and wear at 800 °C... If the wear resistance at °C is defined as 1, then the relative wear resistance of the dual-phase particle-reinforced nickel-based composite coating is 16.7~18.6, and it maintains a high-temperature hardness of 764~813 HV; it has preferential oxidation characteristics and high-temperature friction and softening properties.

2. The method for preparing a high-temperature friction-resistant biphase particle-reinforced nickel-based composite coating by preferential oxidation of components as described in claim 1, characterized in that: Includes the following steps: Step (1): Preparation of powder raw materials: Taking the preparation of 2 kg of biphase particle / nickel-based binder phase mixed powder as an example: Preparation of binder phase powder: Take 640~770 g of nickel-based alloy powder with the following elemental mass percentages: Ni: 69.25%~73.08%, Cr: 15.60%~16.50%, Si: 3.00%~3.70%, B: 2.90%~3.60%, Fe: 4.00%~6.90%, C: 0.62%~0.70%, and a particle size range of 75~148 μm; take 56~64 g of Cu / Mo flux powder with a Cu:Mo ratio of 2:3~3:2 and a particle size range of 48~76 μm; mix the two powders using a planetary ball mill or a V-type mixing drum to obtain a uniformly mixed binder phase powder with good flowability; during planetary ball milling, no milling media are added, the rotation speed is set to 150~180 r / min, and the mixture is mixed at an inclination angle of 38~46° for 8~10 minutes. h; When mixing with a V-shaped mixing drum, set the rotation speed to 50~60 r / min and the mixing time to 12~14 h; Mixing of biphase particles / nickel-based binder phase powder: Take 1174~1296 g of binder phase powder and hard phase powder with W2C / WC biphase, and mix them using a V-shaped drum or roller method; the rotation speed of the roller mixer and V-shaped mixer is set to 30~45 r / min, and the mixing time is 16~20 h; a dry, uniformly mixed biphase particle / nickel-based binder phase mixed powder with good flowability and no obvious W2C / WC biphase particle specific gravity segregation is obtained; Step (2): Pretreatment of substrate material: The substrates used include carbon steel and structural steel. After cleaning the substrate surface by sandblasting, shot peening, grinding with a grinding wheel or steel wool, the substrate surface is cleaned with ethanol or propanol. The substrate is then preheated at 320~400 ℃ for 3~5 h. The preheating equipment includes tube furnace, box furnace and muffle furnace. Step (3): Plasma transfer arc welding: The powder mixture is filled into the powder feeding device of the plasma transfer arc welding system, using argon or nitrogen as the powder feeding and shielding gas; a plasma transfer arc welding coating is prepared on the substrate surface; During plasma transfer arc welding, the welding current is set to 95~105 A, the welding speed is set to 45~60 mm / min, and the powder feed rate is 20~25 g / min; the distance between the welding torch and the substrate is 10~12 mm, the oscillation amplitude is 10~12 mm, and the oscillation speed is 1600~1800 mm / min; the ion gas flow rate is 2~3 L / min, and the shielding gas flow rate is 12~15 L / min. Step (4): Post-weld treatment of coating: After plasma transfer arc welding, the coating is transferred to a heat treatment device and held at 250~300 ℃ for 4~6 h, followed by furnace cooling or air cooling. The heat treatment device includes muffle furnace, box furnace and salt bath furnace; or asbestos mesh is used for slow cooling; or air cooling is performed directly; after cooling, a dual-phase particle-reinforced nickel-based composite coating with preferential oxidation of components to achieve high-temperature friction resistance is obtained.

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