Anti-salt mist surface treatment method for magnesium alloy

Abstract

The invention relates to the technical field of magnesium alloy surface treatment, and discloses a magnesium alloy salt mist prevention surface treatment method which comprises the following steps: step 1, electrophoresis treatment: firstly, carrying out electrophoresis treatment on a magnesium alloy matrix to form a uniform electrophoresis layer; 2, the electrophoresis layer is removed through laser etching, specifically, the electrophoresis layer of the part needing conductive shielding is removed through a laser etching machine, and the magnesium alloy base material body is exposed; 3, conducting oxidation treatment, wherein the magnesium alloy matrix is subjected to yellow conducting oxidation treatment; 4, high-temperature baking is conducted, specifically, baking is conducted for 30 minutes at the high temperature of 220 DEG C; and 5, installing a conductive sealing ring, namely installing the conductive sealing ring in the conductive groove of the magnesium alloy matrix. The invention provides a magnesium alloy salt spray resistant surface treatment method, and solves the problems of insufficient corrosion resistance and single appearance color of magnesium alloy in the prior art.

Description

Technical Field

[0001] The invention relates to the technical field of magnesium alloy surface treatment, in particular to a method for treating a magnesium alloy surface to prevent salt spray. Background Art

[0002] With the continuous advancement of science and technology, the demand for lightweight materials in terminal control products such as drones and automobile control systems is increasing. Magnesium alloy, as a lightweight, high-strength, excellent seismic resistance and good electromagnetic shielding material, is widely considered to be an important choice for terminal control product materials. However, magnesium alloy has poor corrosion resistance, especially in salt spray and hot and humid environments, and is prone to corrosion, which seriously restricts its wide application in terminal control products. Although academia and industry have conducted extensive research on surface protection technologies for magnesium alloys, including micro-arc oxidation, organic coating, electrochemical plating, chemical oxidation, and laser treatment, most of these methods have shortcomings. Specifically, the main problems of the existing technologies include: 1. Insufficient corrosion resistance: Existing surface treatment technologies are difficult to meet the strict test requirements of control terminal products for salt spray resistance, humidity and heat resistance. Under these harsh environments, the surface of magnesium alloys often corrodes rapidly, affecting the service life and reliability of the products. 2. Single appearance color: Although some surface treatment technologies can improve the corrosion resistance of magnesium alloys, they cannot simultaneously meet the demand for diverse appearance colors of control terminal products, limiting the market acceptance of the products; 3. Complex processing technology: Some surface treatment technologies are complex, costly, and have low production efficiency, which is not conducive to large-scale production applications.

[0003] In order to solve the above problems, a method for anti-salt spray surface treatment of magnesium alloy is proposed in the present application. Summary of the invention

[0004] Based on the technical problems existing in the background technology, the present invention proposes a method for surface treatment of magnesium alloy against salt spray.

[0005] The magnesium alloy anti-salt spray surface treatment method proposed by the present invention comprises the following steps: Step 1: electrophoresis treatment, firstly, the magnesium alloy substrate is subjected to electrophoresis treatment to form a uniform electrophoresis layer; Step 2: Use laser engraving to remove the electrophoretic layer. Use a laser engraving machine to remove the electrophoretic layer of the part that needs conductive shielding to expose the magnesium alloy substrate body. Step 3: Conductive oxidation treatment, subjecting the magnesium alloy substrate to yellow conductive oxidation treatment; Step 4: Bake at high temperature, bake at 220 degrees for 30 minutes; Step 5: Install the conductive sealing ring in the conductive groove of the magnesium alloy substrate.

[0006] Preferably, the step 1 of electrophoresis treatment comprises: S1. Surface pretreatment: a1. Cleaning: Use solvent or alkaline solution to clean the magnesium alloy substrate to remove oil, dust and impurities on the surface; a2. Grinding: Through mechanical grinding or sandblasting, further remove the surface oxide scale and tiny protrusions to make the surface smooth; a3. Washing: Rinse the surface thoroughly with pure water to ensure no residue; S2. Electrophoretic coating: a1. Prepare electrophoretic paint solution: according to the process requirements, mix the electrophoretic paint, solvent and additives in proportion; a2. Preparation of electrophoresis tank: Pour the prepared electrophoresis paint solution into the electrophoresis tank, and adjust the tank temperature, pH value and conductivity to the process requirements; a3. Electrophoresis treatment: The pretreated magnesium alloy substrate is used as a cathode or anode, determined according to the type of electrophoretic paint, immersed in an electrophoretic tank, and a certain voltage and time are applied to allow the electrophoretic paint to be deposited on the substrate surface under the action of the electric field to form a uniform electrophoretic layer; S3, electrophoretic layer curing: a1. Rinse: After electrophoresis, rinse the substrate surface with pure water to remove uncured electrophoretic paint; a2. Drying: Place the substrate in an oven and dry it at an appropriate temperature to solidify the electrophoretic layer.

[0007] Preferably, the second step of laser engraving to remove the electrophoretic layer includes: S1. Design laser engraving pattern: According to product requirements, design the pattern of the conductive shielding part where the electrophoretic layer needs to be removed; S2. Preparation of laser engraving machine: Check the working status of the laser engraving machine, ensure that the laser head and focusing mirror components are clean and intact, and adjust the laser power, scanning speed and frequency parameters to the appropriate range; S3, laser engraving treatment: Place the magnesium alloy substrate on the laser engraving machine workbench, perform laser engraving treatment according to the designed pattern, remove the electrophoretic layer of the required part, and expose the magnesium alloy substrate body; S4. Cleaning: After laser engraving, clean the powder and debris remaining on the surface of the substrate.

[0008] Preferably, the step three of conductive oxidation treatment comprises: S1. Solution preparation: According to the requirements of the conductive oxidation process, prepare the conductive oxidation solution, including main salt, oxidant, complexing agent, and corrosion inhibitor components; S2. Pretreatment: Clean and activate the magnesium alloy substrate after laser engraving again to improve the adhesion and uniformity of the conductive oxide layer; S3, conductive oxidation: immerse the substrate in a conductive oxidation solution, apply a certain voltage and time, so that a chemical reaction occurs on the substrate surface to form a yellow conductive oxide layer; S4. Post-treatment: After the conductive oxidation is completed, the substrate surface is rinsed with pure water to remove residual oxidation liquid and impurities.

[0009] Preferably, the step 4 of high temperature baking comprises the following steps: S1. Oven preheating: preheat the oven to 220 degrees; S2. Placing the substrate: placing the magnesium alloy substrate after conductive oxidation treatment into the oven, ensuring that there is enough space between the substrates to allow even heat transfer; S3, baking: baking at 220 degrees for 30 minutes to make the conductive oxide layer more solid and stable; S4. Cooling: After baking, allow the substrate to cool naturally to room temperature in the oven.

[0010] Preferably, the step 5 of installing the conductive sealing ring includes: S1. Prepare a conductive sealing ring: select a suitable conductive sealing ring according to the size and shape of the conductive groove of the magnesium alloy substrate; S2. Clean the conductive slot: Wipe the surface of the conductive slot with detergent or alcohol to remove dust and oil; S3. Install the sealing ring: Place the conductive sealing ring into the conductive groove, ensuring that the sealing ring fits tightly against the groove wall without distortion or misalignment; S4. Check the sealing: After installation, check whether the sealing ring is in good condition and perform a sealing test if necessary.

[0011] The above technical solution of the present invention has the following beneficial technical effects: 1. Significantly improved corrosion resistance: After the treatment, corrosion products only begin to appear on the surface of the magnesium alloy after 96 hours of salt spray test, which is much longer than the salt spray corrosion resistance time of the magnesium alloy matrix before treatment, meeting the strict requirements of the terminal products for corrosion resistance; 2. Rich appearance colors: Conductive oxidation treatment can give magnesium alloys a variety of colors, meeting the needs of terminal products for diverse appearance colors; 3. Simple process and low cost: The processing technology of the present invention is relatively simple, the production cost is low, and it is conducive to large-scale production and application; 4. Strong environmental adaptability: It not only improves the salt spray resistance of magnesium alloy, but also improves its moisture and heat resistance, so that magnesium alloy can maintain good performance and service life in a variety of harsh environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 The present invention provides a flow chart of the magnesium alloy anti-salt spray surface treatment method. DETAILED DESCRIPTION

[0013] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is further described in detail below in conjunction with specific embodiments and with reference to the accompanying drawings. It should be understood that these descriptions are only exemplary and are not intended to limit the scope of the present invention. In addition, in the following description, the description of well-known structures and technologies is omitted to avoid unnecessary confusion of the concept of the present invention.

[0014] like Figure 1 As shown, the magnesium alloy anti-salt spray surface treatment method proposed by the present invention comprises the following steps: Step 1: electrophoresis treatment, firstly, the magnesium alloy substrate is subjected to electrophoresis treatment to form a uniform electrophoresis layer; Step 2: Use laser engraving to remove the electrophoretic layer. Use a laser engraving machine to remove the electrophoretic layer of the part that needs conductive shielding to expose the magnesium alloy substrate body. Step 3: Conductive oxidation treatment, subjecting the magnesium alloy substrate to yellow conductive oxidation treatment; Step 4: Bake at high temperature, bake at 220 degrees for 30 minutes; Step 5: Install the conductive sealing ring in the conductive groove of the magnesium alloy substrate.

[0015] In a specific embodiment, step 1, electrophoresis treatment includes: S1. Surface pretreatment: a1. Cleaning: Use solvent or alkaline solution to clean the magnesium alloy substrate to remove oil, dust and impurities on the surface; a2. Grinding: Through mechanical grinding or sandblasting, further remove the surface oxide scale and tiny protrusions to make the surface smooth; a3. Washing: Rinse the surface thoroughly with pure water to ensure no residue; S2. Electrophoretic coating: a1. Prepare electrophoretic paint solution: according to the process requirements, mix the electrophoretic paint, solvent and additives in proportion; a2. Preparation of electrophoresis tank: Pour the prepared electrophoresis paint solution into the electrophoresis tank, and adjust the tank temperature, pH value and conductivity to the process requirements; a3. Electrophoresis treatment: The pretreated magnesium alloy substrate is used as a cathode or anode, determined according to the type of electrophoretic paint, immersed in an electrophoretic tank, and a certain voltage and time are applied to allow the electrophoretic paint to be deposited on the substrate surface under the action of the electric field to form a uniform electrophoretic layer; S3, electrophoretic layer curing: a1. Rinse: After electrophoresis, rinse the substrate surface with pure water to remove uncured electrophoretic paint; a2. Drying: Place the substrate in an oven and dry it at an appropriate temperature to solidify the electrophoretic layer.

[0016] It should be noted that the cleaning step is the basis for ensuring the quality of electrophoretic coating. Acetone, ethanol or alkaline solution can effectively remove oil, grease, dust and other organic and inorganic impurities on the surface of the magnesium alloy substrate. During the cleaning process, it is necessary to ensure that the solution fully contacts and covers the entire surface. Mechanical stirring or ultrasonic cleaning can be used to enhance the effect if necessary. In the grinding step, mechanical grinding, such as grinding wheel grinding machine or sandblasting, can further remove the surface oxide scale, scratches, and tiny protrusion defects, so that the substrate surface reaches a certain roughness and flatness, which is conducive to the adhesion of electrophoretic paint. After grinding, the surface quality should be checked to ensure that there are no obvious scratches or pits; In the water washing step, after cleaning and polishing, the substrate surface is thoroughly rinsed with pure water to remove residual cleaning agent and polishing dust impurities. This step is crucial to prevent impurities from mixing into the electrophoresis tank liquid.

[0017] In a specific embodiment, step 2 of laser engraving to remove the electrophoretic layer includes: S1. Design laser engraving pattern: According to product requirements, design the pattern of the conductive shielding part where the electrophoretic layer needs to be removed; S2. Preparation of laser engraving machine: Check the working status of the laser engraving machine, ensure that the laser head and focusing mirror components are clean and intact, and adjust the laser power, scanning speed and frequency parameters to the appropriate range; S3, laser engraving treatment: Place the magnesium alloy substrate on the laser engraving machine workbench, perform laser engraving treatment according to the designed pattern, remove the electrophoretic layer of the required part, and expose the magnesium alloy substrate body; S4. Cleaning: After laser engraving, clean the powder and debris remaining on the surface of the substrate.

[0018] It should be noted that: in the design of laser engraving patterns, according to the product appearance and functional requirements, CAD software is used to design the conductive shielding part pattern where the electrophoretic layer needs to be removed. The pattern design should be accurate and clear, and the error and deformation factors in the processing process should be considered. After the design is completed, simulation and verification are required to ensure that the processing effect meets expectations; During the preparation of the laser engraving machine, check whether the working status of the laser engraving machine is normal, including the cleanliness and accuracy of the laser head and focusing lens components, adjust the laser power, scanning speed and frequency parameters to the appropriate range to meet the processing requirements, and ensure that the working environment of the laser engraving machine meets safety regulations and has a stable power supply and cooling system; In the laser engraving process, the magnesium alloy substrate is placed on the laser engraving machine workbench and fixed in position to prevent movement during the processing. The laser engraving program is started and the processing is carried out according to the designed pattern. The laser beam scans and etches the surface of the substrate to remove the electrophoretic layer in the required area to expose the magnesium alloy substrate body. During the processing, it is necessary to pay close attention to the processing effect and adjust the parameters in time to ensure the processing quality; During cleaning, use a vacuum cleaner or compressed air gun to clean the powder and debris remaining on the surface of the substrate after laser engraving. During the cleaning process, avoid scratching the surface of the substrate and ensure that there is no residue that affects the subsequent processing steps and the final quality of the product.

[0019] In a specific embodiment, step three of the conductive oxidation treatment includes: S1. Solution preparation: According to the requirements of the conductive oxidation process, prepare the conductive oxidation solution, including main salt, oxidant, complexing agent, and corrosion inhibitor components; S2. Pretreatment: Clean and activate the magnesium alloy substrate after laser engraving again to improve the adhesion and uniformity of the conductive oxide layer; S3, conductive oxidation: immerse the substrate in a conductive oxidation solution, apply a certain voltage and time, so that a chemical reaction occurs on the substrate surface to form a yellow conductive oxide layer; S4. Post-treatment: After the conductive oxidation is completed, the substrate surface is rinsed with pure water to remove residual oxidation liquid and impurities.

[0020] In a specific embodiment, step 4, high temperature baking comprises the following steps: S1. Oven preheating: preheat the oven to 220 degrees; S2. Placing the substrate: placing the magnesium alloy substrate after conductive oxidation treatment into the oven, ensuring that there is enough space between the substrates to allow even heat transfer; S3, baking: baking at 220 degrees for 30 minutes to make the conductive oxide layer more solid and stable; S4. Cooling: After baking, allow the substrate to cool naturally to room temperature in the oven.

[0021] In a specific embodiment, step five of installing the conductive sealing ring includes: S1. Prepare a conductive sealing ring: select a suitable conductive sealing ring according to the size and shape of the conductive groove of the magnesium alloy substrate; S2. Clean the conductive slot: Wipe the surface of the conductive slot with detergent or alcohol to remove dust and oil; S3. Install the sealing ring: Place the conductive sealing ring into the conductive groove, ensuring that the sealing ring fits tightly against the groove wall without distortion or misalignment; S4. Check the sealing: After installation, check whether the sealing ring is in good condition and perform a sealing test if necessary.

[0022] Working principle of this method: In the process of salt spray and wet heat protection surface treatment of magnesium alloy, electrophoresis treatment is first carried out, and a uniform electrophoresis layer is covered on the surface of the magnesium alloy substrate by electrophoresis technology to enhance the adhesion and corrosion resistance of subsequent treatment. Subsequently, the step of laser engraving to remove the electrophoresis layer is carried out, and the electrophoresis layer of the conductive shielding part is accurately removed by a laser engraving machine to expose the magnesium alloy substrate body to meet specific conductive and shielding requirements. Next, conductive oxidation treatment is carried out, and the magnesium alloy substrate is immersed in a special yellow conductive oxidation liquid, and appropriate voltage and time are applied to cause a chemical reaction on the substrate surface to form a dense conductive oxide layer to enhance its corrosion resistance and conductivity. After that, high-temperature baking is carried out, and the treated magnesium alloy substrate is placed in a high temperature environment of 220 degrees for 30 minutes to solidify the conductive oxide layer and further improve its stability and corrosion resistance. Finally, the step of installing a conductive sealing ring is carried out, and a conductive sealing ring is installed in the conductive groove of the magnesium alloy substrate to ensure that the shell achieves a good sealing effect while conducting electricity, thereby meeting the use requirements of control terminal products for magnesium alloy materials in complex environments.

[0023] It should be understood that the above specific embodiments of the present invention are only used to illustrate or explain the principles of the present invention, and do not constitute a limitation of the present invention. Therefore, any modifications, equivalent substitutions, improvements, etc. made without departing from the spirit and scope of the present invention should be included in the protection scope of the present invention. In addition, the appended claims of the present invention are intended to cover all changes and modifications that fall within the scope and boundaries of the appended claims, or the equivalent forms of such scope and boundaries.

Claims

1. A method for treating magnesium alloy against salt spray, characterized in that: The following steps are involved: Step 1: electrophoresis treatment, firstly, the magnesium alloy substrate is subjected to electrophoresis treatment to form a uniform electrophoresis layer; Step 2: Use laser engraving to remove the electrophoretic layer. Use a laser engraving machine to remove the electrophoretic layer of the part that needs conductive shielding to expose the magnesium alloy substrate body. Step 3: Conductive oxidation treatment, subjecting the magnesium alloy substrate to yellow conductive oxidation treatment; Step 4: Bake at high temperature, bake at 220 degrees for 30 minutes; Step 5: Install the conductive sealing ring in the conductive groove of the magnesium alloy substrate.

2. The method for anti-salt spray surface treatment of magnesium alloy according to claim 1, characterized in that: The step 1 electrophoresis treatment comprises: S1. Surface pretreatment: a1. Cleaning: Use solvent or alkaline solution to clean the magnesium alloy substrate to remove oil, dust and impurities on the surface; a2. Grinding: Through mechanical grinding or sandblasting, further remove the surface oxide scale and tiny protrusions to make the surface smooth; a3. Washing: Rinse the surface thoroughly with pure water to ensure no residue; S2. Electrophoretic coating: a1. Prepare electrophoretic paint solution: according to the process requirements, mix the electrophoretic paint, solvent and additives in proportion; a2. Preparation of electrophoresis tank: Pour the prepared electrophoresis paint solution into the electrophoresis tank, and adjust the tank temperature, pH value and conductivity to the process requirements; a3. Electrophoresis treatment: The pretreated magnesium alloy substrate is used as a cathode or anode, determined according to the type of electrophoretic paint, immersed in an electrophoretic tank, and a certain voltage and time are applied to allow the electrophoretic paint to be deposited on the substrate surface under the action of the electric field to form a uniform electrophoretic layer; S3, electrophoretic layer curing: a1. Rinse: After electrophoresis, rinse the substrate surface with pure water to remove uncured electrophoretic paint; a2. Drying: Place the substrate in an oven and dry it at an appropriate temperature to solidify the electrophoretic layer.

3. The method for surface treatment of magnesium alloy against salt spray according to claim 2, characterized in that: The second step of laser engraving to remove the electrophoretic layer includes: S1. Design laser engraving pattern: According to product requirements, design the pattern of the conductive shielding part where the electrophoretic layer needs to be removed; S2. Preparation of laser engraving machine: Check the working status of the laser engraving machine, ensure that the laser head and focusing mirror components are clean and intact, and adjust the laser power, scanning speed and frequency parameters to the appropriate range; S3, laser engraving treatment: Place the magnesium alloy substrate on the laser engraving machine workbench, perform laser engraving treatment according to the designed pattern, remove the electrophoretic layer of the required part, and expose the magnesium alloy substrate body; S4. Cleaning: After laser engraving, clean the powder and debris remaining on the surface of the substrate.

4. The method for surface treatment of magnesium alloy against salt spray according to claim 3, characterized in that: The step three of conductive oxidation treatment comprises: S1. Solution preparation: According to the requirements of the conductive oxidation process, prepare the conductive oxidation solution, including main salt, oxidant, complexing agent, and corrosion inhibitor components; S2. Pretreatment: Clean and activate the magnesium alloy substrate after laser engraving again to improve the adhesion and uniformity of the conductive oxide layer; S3, conductive oxidation: immerse the substrate in a conductive oxidation solution, apply a certain voltage and time, so that a chemical reaction occurs on the substrate surface to form a yellow conductive oxide layer; S4. Post-treatment: After the conductive oxidation is completed, the substrate surface is rinsed with pure water to remove residual oxidation liquid and impurities.

5. The method for anti-salt spray surface treatment of magnesium alloy according to claim 4, characterized in that: The step 4 high temperature baking comprises the following steps: S1. Oven preheating: preheat the oven to 220 degrees; S2. Placing the substrate: placing the magnesium alloy substrate after conductive oxidation treatment into the oven, ensuring that there is enough space between the substrates to allow even heat transfer; S3, baking: baking at 220 degrees for 30 minutes to make the conductive oxide layer more solid and stable; S4. Cooling: After baking, allow the substrate to cool naturally to room temperature in the oven.

6. The method for anti-salt spray surface treatment of magnesium alloy according to claim 5, characterized in that: The step 5 of installing the conductive sealing ring includes: S1. Prepare a conductive sealing ring: select a suitable conductive sealing ring according to the size and shape of the conductive groove of the magnesium alloy substrate; S2. Clean the conductive slot: Wipe the surface of the conductive slot with detergent or alcohol to remove dust and oil; S3. Install the sealing ring: Place the conductive sealing ring into the conductive groove, ensuring that the sealing ring fits tightly against the groove wall without distortion or misalignment; S4. Check the sealing: After installation, check whether the sealing ring is in good condition and perform a sealing test if necessary.

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