Hard alloy coating and preparation method thereof
By adopting multi-layer different-color spraying technology and nickel coating in cemented carbide coating, the problem of difficulty in time discovering local wear or failure of parts in the prior art is solved, and the high monitoring ability and wear resistance of the coating are achieved.
Patent Information
- Application Number
- CN202411919958.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-25
- Publication Date
- 2025-04-11
- Estimated Expiration
- Not applicable · inactive patent
AI Technical Summary
The existing technology is difficult to detect and monitor local wear or failure of parts in a timely manner, resulting in failure of equipment under high speed, high temperature, high pressure and other working conditions.
Multi-layer carbide coating with different color spray is used to coat the surface of the tungsten carbide powder with nickel, and rare earth oxides and pigment powder are added to form a multi-layer coating with different colors, improving the density and wear resistance of the coating.
Through multi-layer different-color sprayed cemented carbide coating, the monitoring and reliability of the coating are significantly improved, and the wear level of the coating can be promptly indicated, helping workers to grasp the wear status and service life of the parts in a timely manner, and at the same time improving the wear resistance of the coating.
Smart Images
Figure CN119793838A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of new materials, and in particular to a hard alloy coating and a preparation method thereof. Background Art
[0002] Cemented carbide coating is a kind of cemented carbide powder coated on the surface of machinery. It is generally composed of cemented carbide powder and substrate. It is formed by coating cemented carbide powder on substrate at high temperature. This coating has excellent wear resistance, heat resistance, friction resistance and other properties. Cemented carbide coating is often used in high-speed moving parts, such as automobile engine parts, aerospace parts, mechanical equipment parts, etc.
[0003] With the rapid development of modern science and technology and industry, people have higher and higher requirements on the surface performance of various equipment parts. Under working conditions such as high speed, high temperature, high pressure, heavy load and corrosive medium, the failure of parts often starts from the local damage of the material surface, and eventually leads to the paralysis of the entire equipment. At present, it is not easy to find the local wear or failure of parts. Workers generally check key parts based on experience or regularly, and it is difficult to grasp the failure status information of parts in time. Summary of the invention
[0004] In order to overcome the current disadvantage that local wear or failure of parts is not easy to detect, workers generally check key parts based on experience or regularly, and it is difficult to timely grasp the failure status information of parts, the present invention provides a cemented carbide coating and a preparation method thereof to improve the monitorability and reliability of the cemented carbide coating.
[0005] The present invention provides the following technical solutions: A cemented carbide coating comprises at least two layers of cemented carbide coatings prepared based on nickel-coated tungsten carbide powder from a substrate outwards, and each layer of the coating has a different color.
[0006] A method for preparing a cemented carbide coating comprises the following steps: S1. Performing nickel coating treatment on the surface of tungsten carbide powder to obtain nickel-coated tungsten carbide powder; S2. The obtained tungsten carbide powder is evenly distributed into several grinding and stirring containers, and 0.5-1% of rare earth oxide and 0.5-2% of pigment powder are added into the grinding and stirring containers, and then mechanical grinding is performed for 0.5-2h; S3, placing the ground powder in an oven at a temperature of 80-100° C. and drying for 2-3 hours, and obtaining the coating powder after natural cooling for standby use; S4, pre-treating the surface of the substrate to be sprayed, and setting the spraying parameters of the machine spray gun; S5. Preheat the coating powder, and automatically control the spray gun to spray according to preset parameters through the machine program. After reaching the preset spraying thickness, switch to different colors of coating powder for spraying.
[0007] Preferably, the specific steps of performing nickel coating treatment on the surface of tungsten carbide powder by chemical plating process are: S11, cleaning the tungsten carbide powder in ultrasonic water to remove surface impurities and grease, and then drying the powder for standby use; S12, pouring 10 to 30 parts by mass of sodium hypophosphite, 20 to 40 parts by mass of nickel acetate and 5 to 10 parts by mass of sodium citrate into a stirring container and stirring evenly, adjusting the pH value to 9 to 11, and obtaining a chemical nickel plating solution; S13, placing the pretreated tungsten carbide powder into a chemical nickel plating solution, controlling the temperature to 80-90° C. for heating and activation for 1-2 hours; S14, leaving the activated powder in the solution, heating it at 90-100° C. to reduce nickel ions on the surface of the powder for 1-3 hours to form a nickel coating layer; S15. After the chemical nickel plating is completed, the powder is taken out from the solution, washed thoroughly with clean water, and then the powder is dried to obtain nickel-coated tungsten carbide powder.
[0008] Preferably, the weight proportion of graphite powder in the tungsten carbide powder is 4-6%, the weight proportion of Co is 6-8%, the rare earth oxide is CeO2, and the color pigment powder is at least two of red iron oxide, chromium oxide, cobalt blue, and titanium dioxide.
[0009] Preferably, the spraying parameters are: oxygen pressure of 1-3 MPa, flow rate of 800-900 L / h, fuel flow rate of 22.7-25 m 3 / h, the nitrogen pressure of the powder feeding gas is 0.7~1MPa, the flow rate is 7~9L / h, the linear speed of the spray gun is 400~450mm / s, the nozzle angle is 60~90°, the spray distance is 350~400mm, and the coating thickness is controlled at 250~350μm.
[0010] Preferably, the method further comprises heat treating the substrate with a high temperature flame flow before spraying the coating to remove water vapor and dust adhering to the rough surface.
[0011] Preferably, the substrate surface treatment specifically includes the following steps: first use acetone to clean the organic impurities remaining on the substrate surface, use a sandblasting machine to perform sandblasting, the particle size of brown corundum sand is about 200-300 μm, and compressed air is used as the carrier gas. After sandblasting, the compressed air is used to clean the substrate surface to control the substrate surface roughness to 2-4 um.
[0012] Preferably, the specific steps of preheating the powder are: placing the powder in an oven, heating it at 100-120° C. for 20-30 minutes, then cooling it to 40-50° C. in the oven and transferring it to a powder feeder, and the powder feeding amount of tungsten carbide is 75-100 g / min.
[0013] Preferably, in step S5, compressed air is used to cool the coating after each spraying, and the temperature of the coating after spraying is measured with an infrared thermometer. When the temperature rises to 120°C, spraying is stopped immediately, and air cooling is continued until the coating temperature drops to 80°C before spraying is continued.
[0014] Preferably, the step S5 further comprises grinding the coating surface to a roughness of 0.6-0.8 μm, and then irradiating the cemented carbide coating surface with a high-current pulsed electron beam for 10-30 times.
[0015] The present invention has the following beneficial effects: The present invention can provide a more obvious and intuitive prompt of the degree of wear of the coating by performing multi-layer different-color spraying on the surface of the substrate, so that workers can timely grasp the wear state and service life of the substrate material of the parts. By performing nickel coating treatment on the surface of tungsten carbide powder, the porosity of the obtained coating can be reduced, the coating can be made denser and more uniform, and the residual tensile stress of the coating can be reduced. After adding rare earth CeO2, the coating structure can be purified, the density of the coating can be improved, and the quality and performance of the surface hard coating can be improved. After the electron beam modified graphite / hard alloy coating is irradiated with a high-current pulse electron beam, the porosity of the coating can be further reduced, and the surface morphology of the coating after irradiation can be smoother. The graphite added in the coating is transformed into a flaky graphene and diamond structure after the electron beam irradiation, thereby improving the wear resistance of the coating. BRIEF DESCRIPTION OF THE DRAWINGS
[0016] Figure 1 The present invention is a schematic flow chart of a method for preparing a cemented carbide coating according to an embodiment of the present invention. DETAILED DESCRIPTION
[0017] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.
[0018] Example 1: A cemented carbide coating, which comprises two layers of cemented carbide coatings prepared based on nickel-coated tungsten carbide powder from the substrate to the outside, and each layer of the coating has a different color, specifically, green and red from the substrate to the outside.
[0019] refer to Figure 1 As shown, a method for preparing a cemented carbide coating comprises the following steps: S1. Nickel coating the surface of tungsten carbide powder to obtain nickel-coated tungsten carbide powder. The specific steps of using chemical plating process to nickel-coat the surface of tungsten carbide powder are as follows: S11, cleaning the tungsten carbide powder in ultrasonic water to remove surface impurities and grease, and then drying the powder for standby use; S12, pouring 10 parts by mass of sodium hypophosphite, 20 parts by mass of nickel acetate and 5 parts by mass of sodium citrate into a stirring container and stirring evenly, adjusting the pH value to 9, and obtaining a chemical nickel plating solution; S13, placing the pretreated tungsten carbide powder into a chemical nickel plating solution, controlling the temperature to 80-90° C. and heating for activation for 1 hour; S14, leaving the activated powder in the solution, heating it at 90° C. to reduce nickel ions on the powder surface for 1 hour to form a nickel coating layer; S15. After the chemical nickel plating is completed, the powder is taken out from the solution, washed thoroughly with clean water, and then dried to obtain nickel-coated tungsten carbide powder. The weight proportion of graphite powder in the tungsten carbide powder is 4%, the weight proportion of Co is 6%, the rare earth oxide is CeO2, and the color matching pigment powder is chromium oxide and red iron oxide.
[0020] S2. The obtained tungsten carbide powder is evenly distributed into several grinding and stirring containers, and 0.5% of the weight of the tungsten carbide powder and 0.5% of the weight of the pigment powder are added into the grinding and stirring containers, and then mechanical grinding is performed for 0.5h; S3, drying the ground powder in an oven at 80° C. for 2 h, and obtaining a coating powder after natural cooling for later use; S4. Pre-treat the surface of the substrate to be sprayed. Before spraying the coating, use a high-temperature flame flow to heat treat the substrate to remove water vapor and dust adhering to the rough surface; the substrate surface treatment specifically includes the following steps: first use acetone to clean the organic impurities remaining on the substrate surface, use a sandblasting machine to perform sandblasting, the particle size of brown corundum sand is about 200μm, and compressed air is used as the carrier gas. After sandblasting, use compressed air to clean the substrate surface and control the substrate surface roughness to 2um.
[0021] Set the spraying parameters of the machine spray gun: the spraying parameters are: oxygen pressure is 1MPa, flow rate is 800L / h, fuel flow rate is 22.7m 3 / h, the nitrogen pressure of the powder feeding gas is 0.7MPa, the flow rate is 7L / h, the linear speed of the spray gun is 400mm / s, the nozzle angle is 80°, the spray distance is 350mm, and the coating thickness is controlled at 350μm.
[0022] S5, preheating the coating powder, automatically controlling the spray gun to spray according to preset parameters through the machine program, and after reaching the preset spraying thickness, switching to different colors of coating powder for spraying, spraying the red coating powder first and then the green coating powder. Specifically, the specific steps of preheating the powder are: placing the powder in an oven, heating it at 100°C for 20 minutes, then cooling it to 40°C in the oven and transferring it to the powder feeder, and the powder feeding amount of tungsten carbide is 75g / min.
[0023] As a preferred embodiment, in step S5, compressed air is used to cool the coating after each spraying, and the temperature of the coating after spraying is measured with an infrared thermometer. When the temperature rises to 120°C, spraying is stopped immediately, and air cooling is continued until the coating temperature drops to 80°C and then spraying is continued; wherein, the coating surface is polished to a roughness of 0.6μm, and then the surface of the cemented carbide coating is irradiated 10 times with a high-current pulsed electron beam.
[0024] Example 2: A cemented carbide coating, which comprises three layers of cemented carbide coatings prepared based on nickel-coated tungsten carbide powder from the substrate to the outside, and each layer of the coating has a different color, specifically, green, blue and red from the substrate to the outside.
[0025] refer to Figure 1 As shown, a method for preparing a cemented carbide coating comprises the following steps: S1. Nickel coating the surface of tungsten carbide powder to obtain nickel-coated tungsten carbide powder. The specific steps of using chemical plating process to nickel-coat the surface of tungsten carbide powder are as follows: S11, cleaning the tungsten carbide powder in ultrasonic water to remove surface impurities and grease, and then drying the powder for standby use; S12, pouring 30 parts by mass of sodium hypophosphite, 40 parts by mass of nickel acetate and 10 parts by mass of sodium citrate into a stirring container and stirring evenly, adjusting the pH value to 11 to obtain a chemical nickel plating solution; S13, placing the pretreated tungsten carbide powder into a chemical nickel plating solution, and heating and activating the solution at 90° C. for 2 hours; S14, leaving the activated powder in the solution, heating it at 100° C. to reduce nickel ions on the surface of the powder for 3 hours to form a nickel coating layer; S15. After the chemical nickel plating is completed, the powder is taken out from the solution, washed thoroughly with clean water, and then dried to obtain nickel-coated tungsten carbide powder. The weight proportion of graphite powder in the tungsten carbide powder is 6%, the weight proportion of Co is 8%, the rare earth oxide is CeO2, and the color matching pigment powders are chromium oxide, cobalt blue and iron oxide red.
[0026] S2. The obtained tungsten carbide powder is evenly distributed into several grinding and stirring containers, and rare earth oxide accounting for 1% of the weight of the tungsten carbide powder and pigment powder accounting for 2% of the weight of the tungsten carbide powder are added to the grinding and stirring containers, and then mechanical grinding is performed for 2 hours; S3, drying the ground powder in an oven at 100° C. for 3 h, and obtaining a coating powder after natural cooling for later use; S4. Pre-treat the surface of the substrate to be sprayed. Before spraying the coating, use a high-temperature flame flow to heat treat the substrate to remove water vapor and dust adhering to the rough surface; the substrate surface treatment specifically includes the following steps: first use acetone to clean the organic impurities remaining on the substrate surface, use a sandblasting machine to perform sandblasting, the particle size of brown corundum sand is about 300μm, and compressed air is used as the carrier gas. After sandblasting, use compressed air to clean the substrate surface and control the substrate surface roughness to 4um.
[0027] Set the spraying parameters of the machine spray gun: the spraying parameters are: oxygen pressure is 3MPa, flow rate is 900L / h, fuel flow rate is 25m 3 / h, the nitrogen pressure of the powder feeding gas is 1MPa, the flow rate is 9L / h, the linear speed of the spray gun is 450mm / s, the nozzle angle is 90°, the spray distance is 400mm, and the coating thickness is controlled at 250μm.
[0028] S5, preheating the coating powder, automatically controlling the spray gun to spray according to preset parameters through the machine program, and switching to different colors of coating powder for spraying after reaching the preset spraying thickness. Specifically, the specific steps of preheating the powder are: placing the powder in an oven, heating it at 120°C for 30 minutes, then cooling it to 50°C in the oven and transferring it to the powder feeder, and the powder feeding amount of tungsten carbide is 100g / min.
[0029] As a preferred embodiment, in step S5, compressed air is used to cool the coating after each spraying, and the temperature of the coating after spraying is measured with an infrared thermometer. When the temperature rises to 120°C, spraying is stopped immediately, and air cooling is continued until the coating temperature drops to 80°C and then spraying is continued; wherein, the coating surface is polished to a roughness of 0.8μm, and then the surface of the cemented carbide coating is irradiated 20 times with a high-current pulsed electron beam.
[0030] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims
1. A cemented carbide coating, characterized in that: It comprises at least two layers of hard alloy coatings made from nickel-coated tungsten carbide powder from the substrate outwards, and each layer of the coating has a different color.
2. A method for preparing a cemented carbide coating, characterized in that: The following steps are involved: S1. Performing nickel coating treatment on the surface of tungsten carbide powder to obtain nickel-coated tungsten carbide powder; S2. The obtained tungsten carbide powder is evenly distributed into several grinding and stirring containers, and 0.5-1% of rare earth oxide and 0.5-2% of pigment powder are added into the grinding and stirring containers, and then mechanical grinding is performed for 0.5-2h; S3, placing the ground powder in an oven at a temperature of 80-100° C. and drying for 2-3 hours, and obtaining a coating powder after natural cooling, which is set aside; S4, pre-treating the surface of the substrate to be sprayed and setting the spraying parameters of the machine spray gun; S5. Preheat the coating powder, and automatically control the spray gun to spray according to preset parameters through the machine program. After reaching the preset spraying thickness, switch to different colors of coating powder for spraying.
3. The method for preparing a cemented carbide coating according to claim 2, characterized in that: The specific steps of using chemical plating process to nickel-coat the surface of tungsten carbide powder are as follows: S11, cleaning the tungsten carbide powder in ultrasonic water to remove surface impurities and grease, and then drying the powder for standby use; S12, pouring 10 to 30 parts by mass of sodium hypophosphite, 20 to 40 parts by mass of nickel acetate and 5 to 10 parts by mass of sodium citrate into a stirring container and stirring evenly, adjusting the pH value to 9 to 11, and obtaining a chemical nickel plating solution; S13, placing the pretreated tungsten carbide powder into a chemical nickel plating solution, controlling the temperature to 80-90° C. and heating for activation for 1-2 hours; S14, leaving the activated powder in the solution, heating it at 90-100° C. to reduce nickel ions on the surface of the powder for 1-3 hours to form a nickel coating layer; S15. After the chemical nickel plating is completed, the powder is taken out from the solution, washed thoroughly with clean water, and then the powder is dried to obtain nickel-coated tungsten carbide powder.
4. The method for preparing a cemented carbide coating according to claim 2, characterized in that: The weight proportion of graphite powder in the tungsten carbide powder is 4-6%, the weight proportion of Co is 6-8%, the rare earth oxide is CeO2, and the color pigment powder is at least two of iron oxide red, chromium oxide, cobalt blue, and titanium dioxide.
5. The method for preparing a cemented carbide coating according to claim 2, characterized in that: The spraying parameters are: oxygen pressure of 1-3 MPa, flow rate of 800-900 L / h, fuel flow rate of 22.7-25 m 3 / h, the nitrogen pressure of the powder feeding gas is 0.7~1MPa, the flow rate is 7~9L / h, the linear speed of the spray gun is 400~450mm / s, the nozzle angle is 60~90°, the spray distance is 350~400mm, and the coating thickness is controlled at 250~350μm.
6. The method for preparing a cemented carbide coating according to claim 2, characterized in that: The method also includes heat treating the substrate with a high temperature flame flow before spraying the coating to remove water vapor and dust adhering to the rough surface.
7. The method for preparing a cemented carbide coating according to claim 2, characterized in that: The substrate surface treatment specifically includes the following steps: first use acetone to clean the organic impurities remaining on the substrate surface, use a sandblasting machine to perform sandblasting, the brown corundum sand particle size is about 200-300 μm, and compressed air is used as a carrier gas. After sandblasting, the compressed air is used to clean the substrate surface to control the substrate surface roughness to 2-4 μm.
8. The method for preparing a cemented carbide coating according to claim 2, characterized in that: The specific steps of preheating the powder are: placing the powder in an oven, heating it at 100-120° C. for 20-30 minutes, then cooling it to 40-50° C. in the oven and transferring it to a powder feeder, and the powder feeding amount of tungsten carbide is 75-100 g / min.
9. The method for preparing a cemented carbide coating according to claim 2, characterized in that: In step S5, compressed air is used to cool the coating after each spraying, and the temperature of the coating after spraying is measured with an infrared thermometer. When the temperature rises to 120°C, spraying is stopped immediately, and air cooling is continued until the coating temperature drops to 80°C before spraying is continued.
10. The method for preparing a cemented carbide coating according to claim 2, characterized in that: The step S5 also includes grinding the coating surface to a roughness of 0.6-0.8 μm, and then irradiating the cemented carbide coating surface with a high-current pulse electron beam for 10-30 times.