A cold spray method for electroplating nickel-coated micro-sized tungsten carbide particle reinforced aluminum matrix composite coating

Abstract

The present application belongs to the technical field of cold spraying of composite coating, and provides a cold spraying method for electroplating nickel-coated micro-sized tungsten carbide particle reinforced aluminum-based composite coating. First, a nickel layer is electroplated on the surface of 1-3 mu small-sized tungsten carbide particles in a constant-temperature water bath, to obtain nickel-coated tungsten carbide particles. Then, the electroplated nickel-coated tungsten carbide particles and aluminum powder are subjected to low-energy ball milling by using a ball mill, so that the electroplated nickel-coated tungsten carbide particles are uniformly distributed in the aluminum powder, to obtain a mixed powder. By using 1-3 mu micro-sized tungsten carbide particles as raw materials, compared with large-sized tungsten carbide particles, the small-sized tungsten carbide particles can obtain greater acceleration in the cold spraying process, and by plating nickel on the surface, the loss of small-sized tungsten carbide particles in the cold spraying process can be reduced, and the arc-shaped impact effect generated when reaching the surface of the substrate can be reduced, so that the small-sized tungsten carbide particles are more easily retained in the coating.

Description

Technical Field

[0001] The invention belongs to the technical field of cold spraying of composite coatings, in particular to a cold spraying method of an aluminum-based composite coating reinforced with electroplated nickel-coated micro-sized tungsten carbide particles. Background Art

[0002] Tungsten carbide particles have a high melting point, high hardness, high wear resistance, and good wettability with metals such as nickel, cobalt, and iron. They are an important ceramic particle reinforcement material. Tungsten carbide particle reinforced aluminum-based composite coatings are ideal wear-resistant protective coatings that can achieve a good combination of hardness, toughness, and high wear resistance.

[0003] Tungsten carbide particle-reinforced aluminum-based composites are typically manufactured using laser cladding and thermal spraying processes. However, the high temperature environments of these processes can cause thermal decomposition and decarburization of tungsten carbide, causing it to dissolve into the matrix. Brittle phases such as W2C or W appear at the carbide / metal interface in the coating. While the presence of these defects may increase the hardness of the coating, the failure of the crack path provided along the brittle phase will intensify material removal, providing channels for the entry of corrosive fluids, and reducing the wear resistance and corrosion resistance of the coating.

[0004] Cold spray is a solid-state thermal spray process in which particles are accelerated to supersonic speeds (500-1200 m / s) in a gas stream through a Laval nozzle and impact the substrate. Due to the short contact time with the gas, the particles remain in a solid state and the temperature is well below the melting point of the particles. Therefore, the high temperature induces carbide decomposition and / or other avoidable phase changes. The continuous high-speed impact of the particles may produce a shot peening or "ramming" effect, resulting in the densification and deposition of the coating with a density close to the theoretical density. The cold spray process is expected to become an efficient and rapid method for the preparation of tungsten carbide particle reinforced aluminum-based composite coatings. However, due to the characteristics of cold spray deposition technology, on the one hand, the particle size of tungsten carbide particles needs to be in the range of 20-50um, and on the other hand, the coating deposition temperature is low. Therefore, the tungsten carbide particle reinforced aluminum-based composite coating prepared by cold spraying has the following problems: the interface wettability between tungsten carbide and the aluminum substrate is poor, resulting in poor load transfer capacity of tungsten carbide and causing interface fracture. The interface fracture provides a channel for crack propagation during the deformation process due to the lack of intervention of the matrix metal. Even tungsten carbide will form a crack source at the interface due to collision and fragmentation. At the same time, the retention of silicon carbide particles in the coating is low due to sputtering, back-sputtering, and crushing. To this end, the researchers learned from the experience of cold spraying other powder raw materials and found that cold spraying finer ceramic particles (≤5μm) is more likely to embed into the substrate, which is beneficial to avoid the generation of crack sources and improve the performance of the coating. However, since small ceramic particles impacting the substrate will form a bow impact effect, it is difficult for small particles to deposit, resulting in a low degree of cohesive behavior and mechanical interlocking of the coating, which will reduce the performance of the coating. At the same time, the researchers improved the retention rate of tungsten carbide particles in the coating by pre-treating tungsten carbide and nickel powders such as cladding, sintering, crushing and agglomeration, using porous raw material powders, providing sufficient matrix content and pre-treatment before spraying.

[0005] The quality of the bonding between particles in the cold spray process directly determines the conductivity, physical isolation performance, bonding strength and mechanical properties of the deposit. Modifying the particle interface characteristics and effectively regulating the bonding between particles are the prerequisites for achieving performance control of cold spray coatings, repair and remanufacturing of metal components and additive manufacturing components. Therefore, the introduction of surface pretreatment of tungsten carbide reinforcement particles of smaller size (1-3μm) to improve its wetting effect as a particle reinforcement in the metal, strengthen the interface bonding to inhibit interface fracture and improve the retention rate and uniform distribution of tungsten carbide in the coating is expected to improve the overall performance of the composite coating. Summary of the Invention

[0006] In order to solve the above technical problems, the present invention provides a cold spraying method for electroplating nickel-coated micro-sized tungsten carbide particles to reinforce aluminum-based composite coatings. The present invention uses electroplating technology to electroplate nickel on the surface of 1-3μm micro-sized tungsten carbide particles. The nickel-plated tungsten carbide particles help to form a more stable mechanical mixing layer and improve the uniform distribution of tungsten carbide particles. At the same time, after the 1-3μm micro-sized tungsten carbide particles are nickel-plated, the mean free path in the high-speed airflow is reduced, and the air resistance can be better overcome when entering the jet area. In addition, the adhesion of the tungsten carbide particles to the aluminum particles is enhanced after nickel plating, which can reduce the "bow shock wave" impact effect when carried by large-sized aluminum particles, thereby achieving effective deposition. Cold spray technology achieves coating deposition through local metallurgical bonding and mechanical interlocking caused by local plastic deformation of the particle-particle and particle-substrate interfaces. It can avoid the limitations associated with high temperature, will not cause thermal decomposition of tungsten carbide particles and carbon loss, and is conducive to the preparation of high-quality, wear-resistant, heat-corrosion-resistant, lightweight composite coatings with wide applications.

[0007] A cold spraying method for a nickel-plated, micro-sized tungsten carbide particle-reinforced aluminum-based composite coating comprises the following steps:

[0008] Step 1: Electroplating a nickel layer on the surface of 1-3 μm small-sized tungsten carbide particles in a constant temperature water bath to obtain nickel-coated tungsten carbide particles;

[0009] The electroplating process comprises the following steps: first, ultrasonically cleaning the tungsten carbide particles with anhydrous ethanol for 20-30 minutes, then ultrasonically cleaning them with deionized water for 10-15 minutes, and finally drying them; spreading the cleaned tungsten carbide particles on the bottom of a conductive container, with a current density of 0.8-1A / dm2, a temperature of 60-80°C, a time of 30-45 minutes, a pH of 3.6-4.8, and a plating solution temperature not exceeding 95°C; stirring the plating solution once every 5-10 minutes during the electroplating process to ensure the uniformity of the nickel layer on the surface of the tungsten carbide particles; and after the nickel electroplating is completed, separating the nickel-coated tungsten carbide particles and ultrasonically cleaning them with deionized water for 20-30 minutes, and finally drying them;

[0010] Step 2: Using a ball mill to perform low-energy ball milling on the electroplated nickel-coated tungsten carbide particles and aluminum powder, so that the electroplated nickel-coated tungsten carbide particles are evenly distributed in the aluminum powder to obtain a mixed powder;

[0011] The mass ratio of the aluminum powder to the electroplated nickel-coated tungsten carbide particles is (2-3):7;

[0012] The low-energy ball milling process comprises: mixing aluminum powder and electroplated nickel-coated tungsten carbide particles and then loading them into a ball mill jar, evacuating the jar and then introducing argon gas, performing dry milling, with a ball-to-material ratio of (3-4):1, a ball milling speed of 150-200 r / min, and milling for 2-4 hours. The ball mill jar rotates in one direction and stops for 5-10 minutes every 0.5-1 hour of milling to obtain a mixed powder.

[0013] Step 3: cold spraying the mixed powder obtained in step 3 onto a ZE41 magnesium alloy substrate to obtain an electroplated nickel-coated tungsten carbide particle-reinforced aluminum-based composite coating;

[0014] The cold spraying process comprises: ultrasonically cleaning a ZE41 magnesium alloy substrate with anhydrous ethanol for 0.5-1 hour, taking it out and drying it, then sandblasting the surface to be sprayed, and cleaning the surface to be sprayed with an air gun after the treatment; loading the mixed powder obtained in step 3 into a powder feeder, fixing the substrate and cold spraying it with a spray gun, using argon as the powder feeding gas, the cold spraying trajectory is "H"-shaped, the spraying trajectory line spacing is 2-3 mm, the spray beam is at 90 degrees to the surface to be sprayed, the gun speed is 150-200 mm / s, the vertical distance between the gun muzzle and the surface to be sprayed is 30-35 mm, the gas pressure is 3.5-4 MPa, the gas temperature is 550-650° C., and the number of coating layers is 5;

[0015] The mass fraction of Ni in the electroplated nickel-coated tungsten carbide particle-reinforced aluminum-based composite coating obtained in step three is 5%-16%.

[0016] Preferably, the electroplating process in step 1 includes the following steps: first, ultrasonically clean the tungsten carbide particles with anhydrous ethanol for 20 minutes, then ultrasonically clean them with deionized water for 10 minutes, and finally dry them; spread the cleaned tungsten carbide particles on the bottom of a conductive container for electroplating, with a current density of 0.8A / dm2, a temperature of 60°C, a time of 45min, a pH of 3.6-4.8, and a temperature of the electroplating solution not exceeding 95°C. The electroplating solution is stirred once every 10 minutes during the electroplating process to ensure the uniformity of the nickel layer on the surface of the tungsten carbide particles. After the nickel electroplating is completed, the nickel-coated tungsten carbide particles are separated and ultrasonically cleaned with deionized water for 20 minutes, and finally dried.

[0017] Preferably, the electroplating process in step 1 includes the following steps: the electroplating process includes the following steps: first, ultrasonically clean the tungsten carbide particles with anhydrous ethanol for 30 minutes, then ultrasonically clean them with deionized water for 15 minutes, and finally dry them; spread the cleaned tungsten carbide particles on the bottom of the conductive container, current density: 1A / dm2, temperature: 80°C, time: 30min, pH: 3.6-4.8, the temperature of the electroplating solution does not exceed 95°C, and the electroplating solution is stirred once every 5 minutes during the electroplating process to ensure the uniformity of the nickel layer on the surface of the tungsten carbide particles. After the nickel electroplating is completed, the nickel-coated tungsten carbide particles are separated and ultrasonically cleaned with deionized water for 30 minutes, and finally dried.

[0018] Preferably, the purity of the tungsten carbide particles in step 1 is 99.9%, the particles are irregular in shape, and the particle size is 1-3 μm.

[0019] Preferably, the composition of the electroplating solution in step 1 is: 450 g / L nickel sulfamate, 40 g / L boric acid, 20 g / L nickel bromide, and 0.2 g / L sodium lauryl sulfate.

[0020] Preferably, the purity of the aluminum powder in step 2 is 99.9%, the particles are spherical, and the particle size is 20-35 μm.

[0021] Preferably, the ball mill in step 2 is a planetary ball mill.

[0022] Preferably, the low-energy ball milling process in step 2 is as follows: the aluminum powder and the electroplated nickel-coated tungsten carbide particles are mixed and loaded into a ball mill, the ball mill is evacuated, and then argon is introduced. The ball milling process is dry milling, the ball-to-material ratio is 3:1, the ball milling speed is 150r / min, the ball milling is performed for 2h, the ball milling jar rotates in one direction, and stops for 5min every 0.5h of ball milling to obtain a mixed powder.

[0023] Preferably, the low-energy ball milling process in step 2 is as follows: the aluminum powder and the electroplated nickel-coated tungsten carbide particles are mixed and loaded into a ball mill, the ball mill is evacuated, and then argon is introduced. The ball milling process is dry milling, the ball-to-material ratio is 4:1, the ball milling speed is 200r / min, the ball milling is performed for 4h, the ball milling jar rotates in one direction, and stops for 10min after every 1h of ball milling to obtain a mixed powder.

[0024] Preferably, the cold spraying process of step three is: ultrasonic cleaning the sprayed ZE41 magnesium alloy substrate with anhydrous ethanol for 1h, taking out and drying, then sand blasting the surface to be sprayed, and cleaning the surface to be sprayed with an air gun after the treatment; the mixed powder obtained in step three is loaded into a powder feeder, the substrate is fixed, and cold spraying is performed using a spray gun, argon is used as the powder feeding gas, the cold spraying trajectory is "n" shape, the spraying trajectory row spacing is 2mm, the spraying beam flow is 90° to the surface to be sprayed, the row gun speed is 200mm / s, the gun mouth is perpendicular to the surface to be sprayed at a distance of 35mm, the gas pressure is 4MPa, the gas temperature is 650℃, and the coating covers 5 layers.

[0025] Compared with the prior art, the present application has the following beneficial effects:

[0026] 1、The present application uses 1-3μm small size tungsten carbide particles as raw materials, compared with large size tungsten carbide particles, small size tungsten carbide particles can obtain greater acceleration from the airflow during cold spraying, by plating nickel on the surface, it can reduce the loss of small size tungsten carbide particles during cold spraying and reduce the arch impact effect generated when reaching the substrate surface, so as to be more easily retained in the coating.

[0027] 2、The present application uses electroplating technology to plate nickel on the surface of tungsten carbide particles, selects irregular small size tungsten carbide particles, the surface is rough and has greater surface energy compared to large size, which can effectively increase the adhesion of tungsten carbide particles to metal nickel, thereby improving the bonding strength of tungsten carbide particles and nickel layer after plating nickel, and avoiding the phenomenon of nickel layer separation during subsequent cold spraying. In addition, electroplating nickel on the surface of tungsten carbide particles can increase the interface wettability, increase the mechanical locking and chemical bonding between tungsten carbide particles and aluminum matrix, thereby promoting the uniform distribution of tungsten carbide particles in the aluminum matrix, reducing stress concentration, and improving mechanical properties.

[0028] 3、The present application uses cold spraying technology, which can deposit coatings at a lower temperature (usually hundreds of degrees Celsius) and a higher deposition rate (usually the coating deposition can reach millimeter level thickness per minute), the spraying process temperature is much lower than the melting point of aluminum, the mixed powder is affected by heat, no phase change occurs during spraying, which will not cause thermal decomposition and decarburization of tungsten carbide, greatly inhibiting the generation of thermal stress and thermal defects in the coating, having excellent microstructure and mechanical properties, the prepared coating thickness is between tens of microns and dozens of millimeters, and the coating has high bonding strength with the substrate, thereby obtaining aluminum-based composite coating with excellent oxidation resistance, hot corrosion resistance and wear resistance. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 SEM diagram of the nickel-coated tungsten carbide particles obtained in step one of example 1;

[0030] Figure 2 This is an EDS image of the nickel-coated tungsten carbide particles obtained in step 1 of Example 1;

[0031] Figure 3 This is a nickel element distribution spectrum of the nickel-coated tungsten carbide particles obtained in step 1 of Example 1;

[0032] Figure 4 This is a SEM image of the nickel-coated tungsten carbide particles obtained in step 1 of Example 2;

[0033] Figure 5 This is an EDS image of the nickel-coated tungsten carbide particles obtained in step 1 of Example 2;

[0034] Figure 6 Element distribution spectrum of the nickel-coated tungsten carbide particles obtained in step 1 of Example 2;

[0035] Figure 7 This is a cross-sectional morphology of the aluminum-based composite coating reinforced with electroplated nickel coated with 1-3 μm small-sized tungsten carbide particles obtained by cold spraying in step 3 of Example 1;

[0036] Figure 8 This is a cross-sectional coating morphology of the aluminum-based composite coating reinforced with electroplated nickel-coated 1-3 μm small-sized tungsten carbide particles obtained by cold spraying in step 3 of Example 2;

[0037] Figure 9 This is a diagram showing the particle distribution inside the aluminum-based composite coating reinforced with 1-3 μm small-sized tungsten carbide particles coated with electroplated nickel obtained by cold spraying in step 3 of Example 3;

[0038] Figure 10 This is a diagram showing the Ni distribution inside the aluminum-based composite coating reinforced with electroplated nickel coated with 1-3 μm small-sized tungsten carbide particles obtained by cold spraying in step 3 of Example 3;

[0039] Figure 11 This is a diagram of the interface between the electroplated nickel-coated 1-3 μm small-sized tungsten carbide particle reinforced aluminum-based composite coating and the substrate obtained by cold spraying in step 3 of Example 3. DETAILED DESCRIPTION

[0040] The following embodiments of the present invention are described in further detail with reference to the accompanying drawings and examples. The following examples are used to illustrate the present invention but are not intended to limit the scope of the present invention.

[0041] As attached Figure 1 To the attached Figure 11 As shown:

[0042] Specific embodiment 1: The cold spraying method of the present embodiment of the electroplated nickel coated micro-sized tungsten carbide particles reinforced aluminum-based composite coating is carried out in the following steps:

[0043] Step 1: Electroplating a nickel layer on the surface of 1-3 μm micro-sized tungsten carbide particles in a constant temperature water bath to obtain nickel-coated tungsten carbide particles;

[0044] The electroplating process comprises the following steps: first, ultrasonically cleaning the tungsten carbide particles with anhydrous ethanol for 20-30 minutes, then ultrasonically cleaning them with deionized water for 10-15 minutes, and finally drying them; spreading the cleaned tungsten carbide particles on the bottom of a conductive container, with a current density of 0.8-1A / dm2, a temperature of 60-80°C, a time of 30-45 minutes, a pH of 3.6-4.8, and a plating solution temperature not exceeding 95°C; stirring the plating solution once every 5-10 minutes during the electroplating process to ensure the uniformity of the nickel layer on the surface of the tungsten carbide particles; and after the nickel electroplating is completed, separating the nickel-coated tungsten carbide particles and ultrasonically cleaning them with deionized water for 20-30 minutes, and finally drying them;

[0045] Step 2: Using a ball mill to perform low-energy ball milling on the electroplated nickel-coated tungsten carbide particles and aluminum powder, so that the electroplated nickel-coated tungsten carbide particles are evenly distributed in the aluminum powder to obtain a mixed powder;

[0046] The mass ratio of the aluminum powder to the electroplated nickel-coated tungsten carbide particles is (2-3):7;

[0047] The low-energy ball milling process comprises: mixing aluminum powder and electroplated nickel-coated tungsten carbide particles and then loading them into a ball mill jar, evacuating the jar and then introducing argon gas, performing dry milling, with a ball-to-material ratio of (3-4):1, a ball milling speed of 150-200 r / min, and milling for 2-4 hours. The ball mill jar rotates in one direction and stops for 5-10 minutes every 0.5-1 hour of milling to obtain a mixed powder.

[0048] Step 3: cold spraying the mixed powder obtained in step 3 onto a ZE41 magnesium alloy substrate to obtain an electroplated nickel-coated tungsten carbide particle-reinforced aluminum-based composite coating;

[0049] The cold spraying process comprises: ultrasonically cleaning a ZE41 magnesium alloy substrate with anhydrous ethanol for 0.5-1 hour, taking it out and drying it, then sandblasting the surface to be sprayed, and cleaning the surface to be sprayed with an air gun after the treatment; loading the mixed powder obtained in step 3 into a powder feeder, fixing the substrate and cold spraying it with a spray gun, using argon as the powder feeding gas, the cold spraying trajectory is "H"-shaped, the spraying trajectory line spacing is 2-3 mm, the spray beam is at 90 degrees to the surface to be sprayed, the gun speed is 150-200 mm / s, the vertical distance between the gun muzzle and the surface to be sprayed is 30-35 mm, the gas pressure is 3.5-4 MPa, the gas temperature is 550-650° C., and the number of coating layers is 5;

[0050] The mass fraction of nickel in the electroplated nickel-coated tungsten carbide particle reinforced aluminum-based composite coating obtained in step three is 5%-16%.

[0051] This embodiment has the following beneficial effects:

[0052] 1. The present invention uses 1-3μm tiny tungsten carbide particles as raw materials. Compared with large-sized tungsten carbide particles, small-sized tungsten carbide particles can obtain greater acceleration from the airflow during the cold spraying process. By nickel plating their surface, the loss of small-sized tungsten carbide particles during the cold spraying process and the bow impact effect generated when reaching the substrate surface can be reduced, making them easier to retain in the coating.

[0053] 2. The present invention uses electroplating technology to plate nickel on the surface of tungsten carbide particles. Irregular small-sized tungsten carbide particles are selected. The surface is rough and has a larger surface energy than large-sized particles. This can effectively increase the adhesion of tungsten carbide particles to metallic nickel, thereby improving the bonding strength between the tungsten carbide particles and the nickel layer after nickel plating, and avoiding the phenomenon of nickel layer detachment during the subsequent cold spraying process. In addition, electroplating nickel on the surface of tungsten carbide particles can increase interfacial wettability, increase the mechanical locking and chemical bonding between tungsten carbide particles and the aluminum matrix, thereby promoting the uniform distribution of tungsten carbide particles in the aluminum matrix, reducing stress concentration, and improving mechanical properties.

[0054] 3. The present invention adopts cold spraying technology, which can deposit coatings at a lower temperature (usually hundreds of degrees Celsius) and a higher deposition rate (usually the coating deposition can reach a thickness of millimeters per minute). The temperature of the spraying process is much lower than the melting point of aluminum. The mixed powder is affected by heat, and no phase change occurs during the spraying process, which will not cause thermal decomposition and decarburization of tungsten carbide. The generation of thermal stress and thermal defects in the coating is greatly suppressed, and it has excellent microstructure and mechanical properties. The thickness of the prepared coating is between tens of microns and tens of millimeters, and the bonding strength between the coating and the substrate is high, thereby obtaining an aluminum-based composite coating with excellent oxidation resistance, heat corrosion resistance and wear resistance.

[0055] Specific embodiment 2: This embodiment differs from specific embodiment 1 in that: the electroplating process described in step 1 includes the following steps: first, ultrasonically clean the tungsten carbide particles with anhydrous ethanol for 20 minutes, then ultrasonically clean them with deionized water for 10 minutes, and finally dry them; spread the cleaned tungsten carbide particles on the bottom of the conductive container, current density: 0.8A / dm2, temperature: 60℃, time: 45min, pH: 3.6-4.8, the temperature of the plating solution does not exceed 95℃, and the plating solution is stirred once every 10 minutes during the electroplating process to ensure the uniformity of the nickel layer on the surface of the tungsten carbide particles. After the nickel plating is completed, the nickel-coated tungsten carbide particles are separated and ultrasonically cleaned with deionized water for 20 minutes, and finally dried.

[0056] Specific embodiment three: This embodiment differs from specific embodiment one or two in that: the electroplating process in step one includes the following steps: the electroplating process includes the following steps: first, the tungsten carbide particles are ultrasonically cleaned with anhydrous ethanol for 30 minutes, then ultrasonically cleaned with deionized water for 15 minutes, and finally dried; the cleaned tungsten carbide particles are spread flat on the bottom of the conductive container, current density: 1A / dm2, temperature: 80℃, time: 30min, pH: 3.6-4.8, the temperature of the electroplating solution does not exceed 95℃, the electroplating solution is stirred once every 5 minutes during the electroplating process to ensure the uniformity of the nickel layer on the surface of the tungsten carbide particles, after the nickel electroplating is completed, the nickel-coated tungsten carbide particles are separated and ultrasonically cleaned with deionized water for 30 minutes, and finally dried.

[0057] Specific embodiment 4: This embodiment differs from any one of specific embodiments 1 to 3 in that: the purity of the tungsten carbide particles in step 1 is 99.9%, the particles are irregular in shape, and the particle size is 1-3 μm.

[0058] Specific embodiment 5: This embodiment differs from any one of specific embodiments 1 to 4 in that: the composition of the electroplating solution in step 1 is: 450 g / L nickel sulfamate, 40 g / L boric acid, 20 g / L nickel bromide, and 0.2 g / L sodium lauryl sulfate.

[0059] Specific embodiment 6: This embodiment differs from any one of specific embodiments 1 to 5 in that: the purity of the aluminum powder in step 2 is 99.9%, the particles are spherical, and the particle size is 20-35 μm.

[0060] Specific embodiment seven: This embodiment differs from any one of specific embodiments one to six in that: the ball mill in step two is a planetary ball mill.

[0061] Specific embodiment eight: This embodiment differs from any one of specific embodiments one to seven in that: the process of low-energy ball milling described in step two is: aluminum powder and electroplated nickel-coated tungsten carbide particles are mixed and loaded into a ball mill jar, the ball mill jar is evacuated, and then argon gas is introduced. The ball milling process is dry milling, the ball-to-material ratio is 3:1, the ball milling speed is 150r / min, the ball milling is carried out for 2h, the ball mill jar rotates in one direction, and stops for 5min every 0.5h of ball milling to obtain a mixed powder.

[0062] Specific embodiment nine: This embodiment differs from any one of specific embodiments one to eight in that: aluminum powder and electroplated nickel-coated tungsten carbide particles are mixed and loaded into a ball mill, the ball mill is evacuated, and then argon gas is introduced. The ball milling process is dry milling, the ball-to-material ratio is 4:1, the ball milling speed is 200 r / min, the ball milling is carried out for 4 hours, the ball milling jar rotates in one direction, and stops for 10 minutes after every 1 hour of ball milling to obtain a mixed powder.

[0063] Specific embodiment ten: The cold spraying process described in step three is: ultrasonically clean the sprayed ZE41 magnesium alloy substrate with anhydrous ethanol for 1 hour, take it out and dry it, then sandblast the surface to be sprayed, and clean the surface to be sprayed with an air gun after the treatment; the mixed powder obtained in step three is loaded into the powder feeder, and the substrate is fixed and cold sprayed using a spray gun. Argon is used as the powder feeding gas, the cold spray trajectory is "H"-shaped, the spray trajectory line spacing is 2mm, the spray beam is 90° to the surface to be sprayed, the gun speed is 200mm / s, the vertical distance between the muzzle and the surface to be sprayed is 35mm, the gas pressure is 4MPa, the gas temperature is 650℃, and the number of coating coverage layers is 5 layers.

[0064] Example 1:

[0065] The cold spraying method of the present embodiment for the electroplated nickel-coated micro-sized tungsten carbide particle reinforced aluminum-based composite coating is carried out as follows:

[0066] Step 1: Electroplating a nickel layer on the surface of 1-3 μm small-sized tungsten carbide particles in a constant temperature water bath to obtain nickel-coated tungsten carbide particles;

[0067] The electroplating process comprises the following steps: first, ultrasonically cleaning the tungsten carbide particles with anhydrous ethanol for 20 minutes, then ultrasonically cleaning them with deionized water for 10 minutes, and finally drying them; spreading the cleaned tungsten carbide particles flat on the bottom of a conductive container, with a current density of 0.8 A / dm2, a temperature of 60°C, a time of 45 minutes, a pH of 3.6-4.8, and an electroplating solution temperature not exceeding 95°C; stirring the electroplating solution once every 10 minutes during the electroplating process to ensure the uniformity of the nickel layer on the surface of the tungsten carbide particles; and after the nickel electroplating is completed, separating the nickel-coated tungsten carbide particles and ultrasonically cleaning them with deionized water for 20 minutes, and finally drying them;

[0068] Step 2: Using a ball mill to perform low-energy ball milling on the electroplated nickel-coated tungsten carbide particles and aluminum powder, so that the electroplated nickel-coated tungsten carbide particles are evenly distributed in the aluminum powder to obtain a mixed powder;

[0069] The mass ratio of the aluminum powder to the electroplated nickel-coated tungsten carbide particles is 3:7;

[0070] The low-energy ball milling process comprises the following steps: mixing aluminum powder and electroplated nickel-coated tungsten carbide particles and then placing the mixture into a ball mill jar, evacuating the jar and then introducing argon gas, performing dry milling with a ball-to-material ratio of 3:1 and a ball milling speed of 200 rpm for 2 hours, with the jar rotating in one direction and stopping for 5 minutes every 0.5 hours of milling to obtain a mixed powder;

[0071] Step 3: cold spraying the mixed powder obtained in step 3 onto a ZE41 magnesium alloy substrate to obtain an electroplated nickel-coated tungsten carbide particle-reinforced aluminum-based composite coating;

[0072] The cold spraying process comprises: ultrasonically cleaning a ZE41 magnesium alloy substrate with anhydrous ethanol for 0.5-1 hour, taking it out and drying it, then sandblasting the surface to be sprayed, and cleaning the surface to be sprayed with an air gun after the treatment; loading the mixed powder obtained in step 3 into a powder feeder, fixing the substrate and cold spraying it with a spray gun, using argon as the powder feeding gas, the cold spraying trajectory is "H"-shaped, the spraying trajectory line spacing is 2 mm, the spray beam is at 90 degrees to the surface to be sprayed, the gun speed is 200 mm / s, the vertical distance between the gun muzzle and the surface to be sprayed is 30 mm, the gas pressure is 3.5 MPa, the gas temperature is 550°C, and the number of coating layers is 5;

[0073] The nickel content of the aluminum-based composite coating reinforced with 1-3 μm tungsten carbide particles coated with electroplated nickel obtained in this example was 5.02%. Microstructural observation of the aluminum-based composite coating reinforced with 1-3 μm tungsten carbide particles coated with electroplated nickel obtained in this example showed an increase in coating thickness, indicating an increase in deposition and an increase in the tungsten carbide content in the coating, resulting in improved hardness, wear resistance, thermal corrosion resistance, and oxidation resistance. Figure 1 This is a SEM image of the nickel-coated tungsten carbide particles obtained in step 1 of Example 1, indicating that nickel-coated tungsten carbide particles were successfully obtained by electroplating technology; Figure 2 This is an EDS image of the nickel-coated tungsten carbide particles obtained in step 1 of Example 1, illustrating the distribution of nickel elements coated on the surface of the tungsten carbide after electroplating; Figure 3 This is a nickel element distribution spectrum of the nickel-plated tungsten carbide particles obtained in step 1 of Example 1, illustrating the content of nickel elements coated on the surface of the tungsten carbide particles; Figure 7This is a cross-sectional morphology of the electroplated nickel-coated 1-3 μm small-sized tungsten carbide particle-reinforced aluminum-based composite coating obtained by cold spraying in step 3 of Example 1, indicating that the electroplated nickel-coated 1-3 μm small-sized tungsten carbide particle-reinforced aluminum-based composite coating was successfully prepared using cold spraying technology.

[0074] Example 2:

[0075] The cold spraying method of the present embodiment for the electroplated nickel-coated micro-sized tungsten carbide particle reinforced aluminum-based composite coating is carried out as follows:

[0076] Step 1: Electroplating a nickel layer on the surface of 1-3 μm small-sized tungsten carbide particles in a constant temperature water bath to obtain nickel-coated tungsten carbide particles;

[0077] The electroplating process comprises the following steps: first, ultrasonically cleaning the tungsten carbide particles with anhydrous ethanol for 20-30 minutes, then ultrasonically cleaning them with deionized water for 15 minutes, and finally drying them; spreading the cleaned tungsten carbide particles flat on the bottom of a conductive container, applying a current density of 1A / dm2, a temperature of 80°C, a time of 30 minutes, a pH of 3.6-4.8, and an electroplating solution temperature not exceeding 95°C; stirring the electroplating solution once every 5 minutes during the electroplating process to ensure the uniformity of the nickel layer on the surface of the tungsten carbide particles; and after the nickel electroplating is completed, separating the nickel-coated tungsten carbide particles and ultrasonically cleaning them with deionized water for 30 minutes, and finally drying them;

[0078] Step 2: Using a ball mill to perform low-energy ball milling on the electroplated nickel-coated tungsten carbide particles and aluminum powder, so that the electroplated nickel-coated tungsten carbide particles are evenly distributed in the aluminum powder to obtain a mixed powder;

[0079] The mass ratio of the aluminum powder to the electroplated nickel-coated tungsten carbide particles is 3:7;

[0080] The low-energy ball milling process comprises the following steps: mixing aluminum powder and electroplated nickel-coated tungsten carbide particles and then placing the mixture into a ball mill jar, evacuating the jar and then introducing argon gas, performing dry milling with a ball-to-material ratio of 3:1 and a ball milling speed of 200 rpm for 2 hours, with the jar rotating in one direction and stopping for 5 minutes every 0.5 hours of milling to obtain a mixed powder;

[0081] Step 3: cold spraying the mixed powder obtained in step 3 onto a ZE41 magnesium alloy substrate to obtain an electroplated nickel-coated tungsten carbide particle-reinforced aluminum-based composite coating;

[0082] The cold spraying process comprises: ultrasonically cleaning a ZE41 magnesium alloy substrate with anhydrous ethanol for 0.5-1 hour, taking it out and drying it, then sandblasting the surface to be sprayed, and cleaning the surface to be sprayed with an air gun after the treatment; loading the mixed powder obtained in step 3 into a powder feeder, fixing the substrate and cold spraying it with a spray gun, using argon as the powder feeding gas, the cold spraying trajectory is "H"-shaped, the spraying trajectory line spacing is 2 mm, the spray beam is at 90 degrees to the surface to be sprayed, the gun speed is 200 mm / s, the vertical distance between the gun muzzle and the surface to be sprayed is 35 mm, the gas pressure is 4 MPa, the gas temperature is 600°C, and the number of coating layers is 5;

[0083] The nickel content of the aluminum-based composite coating reinforced with 1-3 μm tungsten carbide particles coated with electroplated nickel obtained in this embodiment is 9.16%. The aluminum-based composite coating reinforced with 1-3 μm tungsten carbide particles coated with electroplated nickel obtained in this embodiment not only increases the coating thickness, but also has good internal interface bonding and a denser coating. This increases the surface hardness, wear resistance, thermal corrosion resistance, and oxidation resistance of the magnesium alloy while preventing brittle fracture within the coating due to external environmental influences. Furthermore, due to the improved interface bonding, the service life of the protective coating on the magnesium alloy surface can be extended. Figure 4 This is a SEM image of the nickel-coated tungsten carbide particles obtained in step 1 of Example 2, indicating that nickel-coated tungsten carbide particles were successfully obtained by electroplating technology; Figure 5 This is an EDS image of the nickel-coated tungsten carbide particles obtained in step 1 of Example 2, indicating that the nickel coated on the surface of the tungsten carbide is evenly distributed; Figure 6 This is an element distribution spectrum of the nickel-coated tungsten carbide particles obtained in step 1 of Example 2, indicating that the content of nickel element coated on the surface of the tungsten carbide particles has increased compared with that in Example 1; Figure 8 This is a cross-sectional coating morphology of the electroplated nickel-coated 1-3 μm small-sized tungsten carbide particles reinforced aluminum-based composite coating obtained by cold spraying in step 3 of Example 2, indicating that the electroplated nickel-coated 1-3 μm small-sized tungsten carbide particles reinforced aluminum-based composite coating has good internal bonding, and the coating is dense without large pores and cracks.

[0084] Example 3

[0085] The cold spraying method of the present embodiment for the electroplated nickel-coated micro-sized tungsten carbide particle reinforced aluminum-based composite coating is carried out as follows:

[0086] Step 1: Electroplating a nickel layer on the surface of 1-3 μm small-sized tungsten carbide particles in a constant temperature water bath to obtain nickel-coated tungsten carbide particles;

[0087] The electroplating process comprises the following steps: first, ultrasonically cleaning the tungsten carbide particles with anhydrous ethanol for 30 minutes, then ultrasonically cleaning them with deionized water for 15 minutes, and finally drying them; spreading the cleaned tungsten carbide particles on the bottom of a conductive container, applying a current density of 1 A / dm2, a temperature of 80°C, a time of 30 minutes, a pH of 3.6-4.8, and an electroplating solution temperature not exceeding 95°C; stirring the electroplating solution once every 5 minutes during the electroplating process to ensure the uniformity of the nickel layer on the surface of the tungsten carbide particles; and after the nickel electroplating is completed, separating the nickel-coated tungsten carbide particles, ultrasonically cleaning them with deionized water for 30 minutes, and finally drying them;

[0088] Step 2: Using a ball mill to perform low-energy ball milling on the electroplated nickel-coated tungsten carbide particles and aluminum powder, so that the electroplated nickel-coated tungsten carbide particles are evenly distributed in the aluminum powder to obtain a mixed powder;

[0089] The mass ratio of the aluminum powder to the electroplated nickel-coated tungsten carbide particles is 3:7;

[0090] The low-energy ball milling process comprises the following steps: mixing aluminum powder and electroplated nickel-coated tungsten carbide particles and then placing the mixture into a ball mill jar, evacuating the jar and then introducing argon gas, performing dry milling with a ball-to-material ratio of 3:1 and a ball milling speed of 200 rpm for 2 hours, with the jar rotating in one direction and stopping for 5 minutes every 0.5 hours of milling to obtain a mixed powder;

[0091] Step 3: cold spraying the mixed powder obtained in step 3 onto a ZE41 magnesium alloy substrate to obtain an electroplated nickel-coated tungsten carbide particle-reinforced aluminum-based composite coating;

[0092] The cold spraying process comprises: ultrasonically cleaning a ZE41 magnesium alloy substrate for 1 hour with anhydrous ethanol, taking it out and drying it, then sandblasting the surface to be sprayed, and then cleaning the surface to be sprayed with an air gun; loading the mixed powder obtained in step 3 into a powder feeder, fixing the substrate and cold spraying it with a spray gun, using argon as the powder feeding gas, the cold spraying trajectory is "H"-shaped, the spraying trajectory line spacing is 2 mm, the spray beam is at 90 degrees to the surface to be sprayed, the gun speed is 200 mm / s, the vertical distance between the gun muzzle and the surface to be sprayed is 30 mm, the gas pressure is 4 MPa, the gas temperature is 650°C, and the number of coating layers is 5;

[0093] The mass fraction of nickel in the aluminum-based composite coating reinforced with 1-3 μm micro-sized tungsten carbide particles coated with electroplated nickel obtained in this embodiment is 15.15%. The thickness of the aluminum-based composite coating reinforced with 1-3 μm micro-sized tungsten carbide particles coated with electroplated nickel obtained in this embodiment is increased, and the interface between the coating and the substrate is well bonded, preventing the coating and the substrate from being separated due to the external environment, thereby improving the service life of the magnesium alloy. In addition, since the tungsten carbide particles are coated with electroplated nickel, the retention rate of tungsten carbide is increased, which is of great significance for filling pores in the coating, reducing the crack propagation caused by the generation of crack sources and the ingress of corrosive liquids or gases. At the same time, the wettability of the coated tungsten carbide with aluminum particles is improved, and the filling effect of tungsten carbide is enhanced, thereby increasing the density of the coating. Therefore, the surface hardness, wear resistance, heat corrosion resistance and oxidation resistance of the magnesium alloy are all improved to varying degrees. Figure 9 This is a diagram showing the particle distribution within the aluminum-based composite coating reinforced with electroplated nickel-coated 1-3 μm small-sized tungsten carbide particles obtained by cold spraying in step 3 of Example 3, illustrating that the small-sized WC particles are uniformly embedded in the aluminum-aluminum interface that is mechanically interlocked after plastic deformation; Figure 10 This is a diagram of the nickel distribution state inside the aluminum-based composite coating reinforced with electroplated nickel-coated 1-3 μm small-sized tungsten carbide particles obtained by cold spraying in step 3 of Example 3, indicating that the presence of nickel plays an important role in the deposition of small-sized tungsten carbide. Figure 11 This is the interface between the electroplated nickel-coated 1-3 μm small-size tungsten carbide particles reinforced aluminum-based composite coating and the substrate obtained by cold spraying in step 3 of Example 3. It shows that the coating is well bonded to the ZE41 magnesium alloy substrate, and no large cracks or pores are found at the interface.

[0094] The embodiments of the present invention are provided for the purpose of illustration and description. Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations of the present invention. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. A cold spraying method for a nickel-plated, micro-sized tungsten carbide particle-reinforced aluminum-based composite coating, characterized by: The following steps are involved: Step 1: First, in a constant temperature water bath, a nickel layer is electroplated on the surface of 1-3 μm small-sized tungsten carbide particles using an electroplating process to obtain nickel-coated tungsten carbide particles; The electroplating process The following steps are involved: S11, first ultrasonically clean the tungsten carbide particles with anhydrous ethanol for 20-30 minutes, then ultrasonically clean them with deionized water for 10-15 minutes, and finally dry them; S12, then spread the cleaned tungsten carbide particles on the bottom of a conductive container for electroplating, with a current density of 0.8A / dm2, a temperature of 60°C, a time of 45 minutes, a pH of 3.6-4.8, and a temperature of the electroplating solution not exceeding 95°C. The electroplating solution is stirred once every 10 minutes during the electroplating process to ensure the uniformity of the nickel layer on the surface of the tungsten carbide particles; S13, after the nickel plating is completed, the nickel-plated tungsten carbide particles are separated and ultrasonically cleaned with deionized water for 20 minutes, and finally dried; The purity of the tungsten carbide particles is 99.9%, the particles are irregular in shape, and the particle size is 1-3 μm. The composition of the electroplating solution is: 450 g / L nickel sulfamate, 40 g / L boric acid, 20 g / L nickel bromide, and 0.2 g / L sodium lauryl sulfate. Step 2: Then, the nickel-plated tungsten carbide particles and the aluminum powder are subjected to low-energy ball milling in a ball mill to uniformly distribute the nickel-plated tungsten carbide particles in the aluminum powder to obtain a mixed powder; The purity of the aluminum powder is 99.9%, the particles are spherical, and the particle size is 20-35 μm. The ball mill is a planetary ball mill. The mass ratio of the aluminum powder to the electroplated nickel-coated tungsten carbide particles is (2-3):7; The process of the low-energy ball milling is as follows: S21, firstly, mixing aluminum powder and electroplated nickel-coated tungsten carbide particles and then loading them into a ball mill; S22, the ball mill was evacuated and then introduced with argon gas, and the ball milling process was dry milling with a ball-to-material ratio of (3-4):1, a ball milling speed of 150-200 r / min, and the ball milling was performed for 2-4 h. The ball mill rotated in one direction and stopped for 5-10 min every 0.5-1 h to obtain a mixed powder; Step 3: Then, the mixed powder obtained in step 3 is sprayed on a ZE41 magnesium alloy substrate by cold spraying to obtain an electroplated nickel-coated tungsten carbide particle-reinforced aluminum-based composite coating; The cold spraying process is as follows: S31, ultrasonically cleaning the sprayed ZE41 magnesium alloy substrate with anhydrous ethanol for 0.5-1 hour, taking it out and drying it; S32, then sandblasting the surface to be sprayed, and after the treatment, cleaning the surface to be sprayed with an air gun; S33. Finally, the mixed powder obtained in step 3 is loaded into a powder feeder. After fixing the substrate, cold spraying is performed using a spray gun. Argon is used as the powder feeding gas. The cold spray trajectory is in the shape of an "H" with a spray trajectory line spacing of 2-3 mm. The spray beam is at 90 degrees to the surface to be sprayed. The gun speed is 150-200 mm / s. The vertical distance between the gun muzzle and the surface to be sprayed is 30-35 mm. The gas pressure is 3.5-4 MPa, the gas temperature is 550-650°C, and the number of coating layers is 5. The mass fraction of Ni in the electroplated nickel-coated tungsten carbide particle-reinforced aluminum-based composite coating is 5%-16%.

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