Aluminum-copper alloy surface coating method
Through workpiece pretreatment, plasma treatment and annealing processes, the problems of cleanliness and uneven structure during the aluminum-copper alloy surface coating process were solved, and the aluminum-copper alloy coating effect with high adhesion, hardness and wear resistance was achieved.
Patent Information
- Application Number
- CN202510735818.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-04
- Publication Date
- 2025-09-26
AI Technical Summary
In the existing aluminum-copper alloy surface coating process, insufficient cleanliness leads to incomplete film deposition and uneven structure, which in turn generates internal stress and makes the film prone to cracking and peeling.
A combined method of workpiece pretreatment, plasma treatment, chemical pickling, CVD deposition and annealing treatment is used, including the use of organic solvent cleaning, chemical pickling, plasma bombardment, selection of appropriate gas and airflow, control of gas pressure and temperature, combined with annealing treatment to improve surface cleanliness and film structure.
It improves the adhesion and surface hardness of the coating, reduces internal stress, ensures the integrity and wear resistance of the film, and enhances the stability of the aluminum-copper alloy surface.
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Abstract
Description
Technical Field
[0001] The invention relates to the technical field of aluminum-copper alloy coating, in particular to a method for coating the surface of an aluminum-copper alloy. Background Art
[0002] Copper-aluminum alloy is an alloy material primarily composed of copper and aluminum. It is produced by fusing copper and aluminum in a specific ratio and then casting, forging, or other processing techniques. Aluminum has a relatively low density, while copper has a higher density. The density of copper-aluminum alloy lies somewhere in between, varying depending on the copper-to-aluminum ratio. Compared to pure aluminum, copper-aluminum alloys exhibit significantly improved strength and hardness. The addition of copper refines the alloy's grain structure, producing solid solution strengthening and dispersion strengthening, enabling the alloy to withstand greater external forces. Furthermore, appropriate heat treatment processes can further enhance its strength and hardness. Coating is often performed on the surface of copper-aluminum alloys to improve their hardness and wear resistance. However, conventional coating processes for common aluminum-copper alloys often result in incomplete film deposition due to insufficient surface cleanliness. This leads to structural inhomogeneity during film growth, resulting in internal stresses that can gradually accumulate. This can cause the film to become unstable and susceptible to cracking and flaking. Therefore, a method for coating the surface of an aluminum-copper alloy is provided. Summary of the Invention
[0003] The purpose of the present invention is to provide a method for coating the surface of an aluminum-copper alloy in response to the above technical problems, so as to solve the shortcomings of the existing aluminum-copper alloy surface coating, such as insufficient surface cleanliness, incomplete film deposition, uneven structure during film growth, and internal stress.
[0004] To achieve this purpose, the present invention provides a method for coating the surface of an aluminum-copper alloy, which adopts the following technical embodiments: A method for coating an aluminum-copper alloy surface, comprising the following steps: S1: Workpiece pretreatment: Use organic solvent to wipe the surface of aluminum-copper alloy workpiece to remove oil, grease and other organic pollutants; S2: Chemical pickling is used to remove the surface oxide layer, making the surface atoms more active and conducive to the deposition of thin films; S3: Plasma treatment technology is used to generate plasma in a low-pressure gas environment, and high-energy particles in the plasma are used to bombard the surface of the workpiece to activate surface atoms; S4: Select appropriate reaction gases and inert gases based on the thin film material to be deposited. During the reaction process, they mainly play the role of stabilizing the gas flow and preventing local overheating in the reaction chamber. S5: Place the pre-treated workpiece into the reaction chamber of the CVD equipment, close the reaction chamber and start vacuuming; S6: Introduce carrier gas. After the carrier gas flows steadily, gradually introduce the reaction gas. S7: Start the heating system to raise the temperature of the reaction chamber to the set value, and the reaction gas undergoes a chemical reaction under the action of the high temperature and the catalyst; S8: After the deposition is completed, stop introducing the reaction gas and turn off the heating system. Let the reaction chamber cool naturally. S9: When the temperature of the reaction chamber drops to room temperature, the reaction chamber is opened, the coated workpiece is taken out, the workpiece is cleaned with an organic solvent, and then rinsed with deionized water; S10: Post-processing the coated workpiece, performing annealing treatment, and heat treating the workpiece at high temperature.
[0005] Preferably, in step S1, the organic solvent is any one of ethanol solution, isopropanol solution, acetone solution, butanone solution, and trichloroethylene solution.
[0006] Preferably, in step S2, chemical pickling uses a chemical pickling agent, and the chemical pickling agent is any one of dilute sulfuric acid, dilute hydrochloric acid, phosphoric acid, and hydrofluoric acid.
[0007] Preferably, in step S4, the reaction gas is any one of argon, oxygen, hydrogen and nitrogen.
[0008] Preferably, in step S4, the inert gas is any one of argon, helium, and neon, and the inert gas is different from the reaction gas.
[0009] Preferably, in step S5, vacuum is applied and the air pressure is controlled at 10-100 Pa.
[0010] Preferably, in step S6, when the gas is introduced, the gas flow rate is 20-100 sccm.
[0011] Preferably, in step S7, at 13.56 MHz, the radio frequency power is 200-500 W, and the surface temperature of the aluminum-copper alloy may be 300-500° C.
[0012] Preferably, in step S9, the organic solvent is any one of ethanol solution, isopropanol solution, acetone solution, butanone solution, and trichloroethylene solution.
[0013] Preferably, in step S10, an annealing treatment is performed, wherein the workpiece is heat-treated at a temperature 300-500° C. lower than the deposition temperature to improve the crystal structure and adhesion of the thin film.
[0014] The present invention has at least the following beneficial effects: In the present invention, the aluminum alloy parts are pretreated by using a combination of a weak alkaline solution and a strong alkaline solution to remove oil stains, impurities and natural oxide film on the surface of the aluminum alloy, so that the subsequent oxidation process is more stable, the cleanliness of the workpiece is improved, and the deposition of the thin film is facilitated.
[0015] In the present invention, plasma treatment can increase the activity of the aluminum-copper alloy surface. High-energy particles bombarding the surface disrupt the chemical bonds of surface atoms, creating dangling bonds and increasing the surface energy. This makes it easier for surface atoms to chemically react or physically adsorb with atoms of the subsequent coating material, significantly improving the adhesion of the coating. By selecting different gases and processing parameters, the chemical and physical properties of the aluminum-copper alloy surface can be precisely controlled. Nitrogen plasma can be used to form a nitride layer on the surface, improving the hardness and wear resistance of the surface. The plasma treatment speed is relatively fast.
[0016] In the present invention, during the annealing process, the atoms in the film gain sufficient energy to rearrange and diffuse. For thin films deposited on aluminum-copper alloy surfaces via chemical vapor deposition, annealing can increase grain size and completeness, reducing crystal defects. During the coating process, internal stress is generated within the film due to differences in thermal expansion coefficients between the film and the substrate, as well as structural inhomogeneities during film growth. Annealing can release this internal stress due to the thermal motion of the film atoms.
[0017] Other advantages, objectives and features of the present invention will be reflected in part through the following description, and in part will be understood by those skilled in the art through study and practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] Figure 1 This is a flow chart of Example 1 of a method for coating an aluminum-copper alloy surface according to the present invention; Figure 2 This is a flow chart of Example 2 of a method for coating an aluminum-copper alloy surface according to the present invention; Figure 3 This is a flow chart of Example 3 of a method for coating an aluminum-copper alloy surface according to the present invention. DETAILED DESCRIPTION
[0019] In order to make the purpose, technical embodiments and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. Example 1
[0020] The surface coating method of aluminum-copper alloy in this embodiment is as follows: (1) Workpiece pretreatment: Use ethanol solution to wipe the surface of aluminum-copper alloy workpiece to remove oil, grease and other organic pollutants; (2) Use dilute sulfuric acid to remove the surface oxide layer, making the surface atoms more active and conducive to the deposition of thin films; (3) Using plasma treatment technology to generate plasma in a low-pressure gas environment, using high-energy particles in the plasma to bombard the surface of the workpiece and activate surface atoms; (4) Oxygen is selected as the reaction gas and argon as the inert gas according to the thin film material to be deposited. During the reaction process, it mainly plays the role of stabilizing the airflow and preventing local overheating in the reaction chamber; (5) Place the pretreated workpiece into the reaction chamber of the CVD equipment, close the reaction chamber and start vacuuming, with the pressure controlled at 10-100 Pa; (6) Introduce carrier gas, and after the carrier gas flows steadily, gradually introduce the reaction gas; (7) Start the heating system and raise the temperature of the reaction chamber to the set value. The reaction gas undergoes a chemical reaction under the action of high temperature and catalyst. The radio frequency is maintained at 13.56 MHz and the radio frequency power is 200-500 W. The surface temperature of the aluminum-copper alloy may be 300-500 °C. (8) After the deposition is completed, stop introducing the reaction gas and turn off the heating system. Let the reaction chamber cool naturally; (9) When the temperature of the reaction chamber drops to room temperature, open the reaction chamber, take out the coated workpiece, clean the workpiece with ethanol solution, and then rinse it with deionized water; (10) The coated workpiece is post-processed and annealed, and the workpiece is heat treated at 300-500°C below the deposition temperature. Example 2
[0021] The surface coating method of aluminum-copper alloy in this embodiment is as follows: (1) Workpiece pretreatment: Use ethanol solution to wipe the surface of aluminum-copper alloy workpiece to remove oil, grease and other organic pollutants; (2) Use dilute sulfuric acid to remove the surface oxide layer, making the surface atoms more active and conducive to the deposition of thin films; (3) Using plasma treatment technology to generate plasma in a low-pressure gas environment, using high-energy particles in the plasma to bombard the surface of the workpiece and activate surface atoms; (4) Oxygen is selected as the reaction gas and argon as the inert gas according to the thin film material to be deposited. During the reaction process, it mainly plays the role of stabilizing the airflow and preventing local overheating in the reaction chamber; (5) Place the pretreated workpiece into the reaction chamber of the CVD equipment, close the reaction chamber and start vacuuming, with the pressure controlled at 10-100 Pa; (6) Introduce carrier gas, and after the carrier gas flows steadily, gradually introduce the reaction gas; (7) Start the heating system and raise the temperature of the reaction chamber to the set value. The reaction gas undergoes a chemical reaction under the action of high temperature and catalyst. The radio frequency is maintained at 13.56 MHz and the radio frequency power is 200-500 W. The surface temperature of the aluminum-copper alloy may be 300-500 °C. (8) After the deposition is completed, stop introducing the reaction gas and turn off the heating system. Let the reaction chamber cool naturally; (9) When the temperature of the reaction chamber drops to room temperature, open the reaction chamber, take out the coated workpiece, clean the workpiece with ethanol solution, and then rinse it with deionized water. Example 3
[0022] The surface coating method of aluminum-copper alloy in this embodiment is as follows: (1) Using plasma treatment technology, plasma is generated in a low-pressure gas environment, and high-energy particles in the plasma are used to bombard the surface of the workpiece to activate surface atoms; (2) Oxygen is selected as the reaction gas and argon as the inert gas according to the thin film material to be deposited. During the reaction process, it mainly plays the role of stabilizing the airflow and preventing local overheating in the reaction chamber; (3) Place the pretreated workpiece into the reaction chamber of the CVD equipment, close the reaction chamber and start vacuuming, with the pressure controlled at 10-100 Pa; (4) Introduce carrier gas, and after the carrier gas flows steadily, gradually introduce the reaction gas; (5) Start the heating system and raise the temperature of the reaction chamber to the set value. The reaction gas undergoes a chemical reaction under the action of high temperature and catalyst. The radio frequency is maintained at 13.56 MHz and the radio frequency power is 200-500 W. The surface temperature of the aluminum-copper alloy may be 300-500 °C. (6) After the deposition is completed, stop introducing the reaction gas and turn off the heating system. Let the reaction chamber cool naturally.
[0023] Comparative Examples 1-3, Example 1 is compared with Examples 2-3, with the addition of workpiece pretreatment, oxide layer removal, and annealing after deposition. The aluminum alloy parts are pretreated, and a combination of a weak alkaline solution and a strong alkaline solution is used to remove oil stains and impurities on the surface of the aluminum alloy as well as the natural oxide film, making the subsequent oxidation process more stable, improving the cleanliness of the workpiece, and facilitating the deposition of the film. During the annealing process, the atoms in the film obtain enough energy to rearrange and diffuse. For a film plated on the surface of an aluminum-copper alloy by chemical vapor deposition, annealing can make the grains in the film grow and tend to be complete, reducing crystal defects. During the coating process, due to the different thermal expansion coefficients of the film and the matrix material, and the uneven structure during the film growth process, internal stress will be generated inside the film. During annealing, the thermal motion of the film atoms can release the internal stress. The overall plasma treatment can increase the activity of the aluminum-copper alloy surface. High-energy particles bombarding the surface can break the chemical bonds of the surface atoms, generating dangling bonds, thereby increasing the surface energy. This makes it easier for surface atoms to chemically react or physically adsorb with the atoms of subsequent coating materials, significantly improving the adhesion of the coating. By selecting different gases and processing parameters, the chemical and physical properties of the aluminum-copper alloy surface can be precisely controlled. Nitrogen plasma can form a nitride layer on the surface, improving the surface hardness and wear resistance. The plasma processing speed is relatively fast.
[0024] The above embodiments are only used to illustrate rather than limit the technical embodiments of the present invention. Relevant technicians in this field can make reasonable modifications or equivalent substitutions to the present invention, but any modifications and partial substitutions that do not depart from the spirit and scope of the present invention should be included in the scope of the claims of the present invention.
[0025] The contents not described in detail in this specification belong to the prior art known to those skilled in the art.
Claims
1. A method for coating the surface of an aluminum-copper alloy, characterized in that: The aluminum-copper alloy surface coating method comprises the following steps: S1: Workpiece pretreatment: Use organic solvent to wipe the surface of aluminum-copper alloy workpiece to remove oil, grease and other organic pollutants; S2: Chemical pickling is used to remove the surface oxide layer, making the surface atoms more active and conducive to the deposition of thin films; S3: Plasma treatment technology is used to generate plasma in a low-pressure gas environment, and high-energy particles in the plasma are used to bombard the surface of the workpiece to activate surface atoms; S4: Select appropriate reaction gases and inert gases based on the thin film material to be deposited. During the reaction process, they mainly play the role of stabilizing the gas flow and preventing local overheating in the reaction chamber. S5: Place the pre-treated workpiece into the reaction chamber of the CVD equipment, close the reaction chamber and start vacuuming; S6: Introduce carrier gas. After the carrier gas flows steadily, gradually introduce the reaction gas. S7: Start the heating system to raise the temperature of the reaction chamber to the set value, and the reaction gas undergoes a chemical reaction under the action of the high temperature and the catalyst; S8: After the deposition is completed, stop introducing the reaction gas and turn off the heating system. Let the reaction chamber cool naturally. S9: When the temperature of the reaction chamber drops to room temperature, the reaction chamber is opened, the coated workpiece is taken out, the workpiece is cleaned with an organic solvent, and then rinsed with deionized water; S10: Post-processing the coated workpiece, performing annealing treatment, and heat treating the workpiece at high temperature.
2. The method for coating the surface of an aluminum-copper alloy according to claim 1, wherein: In step S1, the organic solvent is any one of ethanol solution, isopropanol solution, acetone solution, butanone solution, and trichloroethylene solution.
3. The method for coating the surface of an aluminum-copper alloy according to claim 1, wherein: In step S2, chemical pickling uses a chemical pickling agent, which is any one of dilute sulfuric acid, dilute hydrochloric acid, phosphoric acid, and hydrofluoric acid.
4. The method for coating the surface of an aluminum-copper alloy according to claim 1, wherein: In step S4, the reaction gas is any one of argon, oxygen, hydrogen, and nitrogen.
5. The method for coating the surface of an aluminum-copper alloy according to claim 1, wherein: In step S4, the inert gas is any one of argon, helium, and neon, and the inert gas is different from the reaction gas.
6. The method for coating the surface of an aluminum-copper alloy according to claim 1, wherein: In step S5, vacuum is applied and the air pressure is controlled at 10-100 Pa.
7. The method for coating the surface of an aluminum-copper alloy according to claim 1, wherein: In step S6, when the gas is introduced, the gas flow rate is 20-100 sccm.
8. The method for coating the surface of an aluminum-copper alloy according to claim 1, wherein: In step S7, at 13.56 MHz, the radio frequency power is 200-500 W, and the surface temperature of the aluminum-copper alloy may be 300-500° C.
9. The method for coating the surface of an aluminum-copper alloy according to claim 1, wherein: In step S9, the organic solvent is any one of ethanol solution, isopropyl alcohol solution, acetone solution, butanone solution, and trichloroethylene solution.
10. The method for coating the surface of an aluminum-copper alloy according to claim 1, wherein: In step S10, an annealing treatment is performed, wherein the workpiece is heat-treated at a temperature 300-500° C. lower than the deposition temperature to improve the crystal structure and adhesion of the thin film.