Process method for hard anode oxidation film forming

Abstract

The invention relates to a surface treatment method of a hard anode, aims to solve the common problems of long oxidation working time, high energy consumption in the technical process and the like in the treatment process of hard anode oxidation, and provides a hard anode oxidation film-forming technical method which comprises the following steps: hanging, degreasing, alkali etching, film stripping, anode oxidation, hole sealing and hanging. Wherein an anodic oxidation tank solution for anodic oxidation comprises 140-180 g / L of sulfuric acid, 48-120 g / L of aluminum sulfate octadecahydrate and 3-7 g / L of a glycollic acid solution with the mass concentration of 25-30%; and / or the addition amount of sodium metasilicate in the hole sealing groove is 2-4g / L. The efficiency of an existing hard anodizing process is greatly improved, the production energy consumption is reduced, and the production cost is reduced.

Description

Technical Field

[0001] This invention relates to a surface treatment method for hard anodes, and more specifically to a process method for hard anode oxidation film formation. Background Technology

[0002] Hard anodizing is a surface treatment technology that uses electrochemical methods to form a hard anodic oxide film on a metal surface. The film thickness typically exceeds 50 μm, and in some cases even reaches 100 μm. This oxide film exhibits excellent corrosion resistance, wear resistance, and insulation, and is widely used in aerospace, automotive manufacturing, semiconductor equipment, and medical devices. In the hard anodizing process, the metal workpiece acts as the anode, placed in an electrolyte. By applying direct current, alternating current, or pulsed current, an oxidation reaction occurs on the metal surface, forming a dense oxide film. The electrolyte is usually a sulfuric acid solution or a mixed acid solution (a mixture of multiple acids), combined with a low-temperature bath environment. Different component ratios and concentrations significantly affect the performance of the oxide film and the processing time.

[0003] Currently, hard anodizing is increasingly widely used in industry, especially in the semiconductor equipment sector. However, the process is generally plagued by problems such as long oxidation times and high energy consumption. Hard anodizing typically requires a film thickness of 50µm or more. Commonly used oxidation working solutions achieve an oxide film growth rate of 0.2µm / min-0.3µm / min, with an oxidation time of 3-4.5 hours. Therefore, an oxidation line usually needs to be equipped with multiple stations and rectifiers to meet production requirements.

[0004] In conventional hard anodizing processes, a constant current operating mode is typically used to better control the oxide film thickness. The current remains constant throughout the process. However, as the oxide film thickness increases, the product resistance gradually increases, and the operating voltage for hard anodizing gradually rises with the working time. When the film thickness reaches 50µm or more, the voltage can typically reach around 150V, and energy consumption increases rapidly over time. Simultaneously, a significant amount of heat is generated during hard anodizing. To maintain the low temperature of the bath solution, strong cooling is necessary, requiring a chiller to run continuously. Furthermore, traditional pure water sealing methods are time-consuming, generally requiring more than 4 hours, and the sealing temperature must reach above 95 degrees Celsius. Summary of the Invention

[0005] To address the problems of long oxidation time and high energy consumption in hard anodizing, this invention proposes a process for film formation in hard anodizing, which greatly improves the efficiency of existing hard anodizing processes, reduces production energy consumption, and lowers production costs.

[0006] This invention is achieved through the following technical solution: a process for rapid film formation in hard anodizing, comprising conventional methods of top hanging, degreasing, alkaline etching, film stripping, anodizing, sealing, and bottom hanging. The anodizing bath solution includes sulfuric acid, aluminum sulfate octadecyl hydrate, and a 25-30% glycolic acid solution. The amounts used are: sulfuric acid: 140-180 g / L; aluminum sulfate octadecyl hydrate: 48-120 g / L; and 25-30% glycolic acid solution: 3-7 g / L.

[0007] Preferably, the anodizing bath solution is mixed and then placed into the anodizing bath solution for anodizing at a temperature of -4 to 0℃ and a current density of 1.5 to 2.5 A / dm³. 2 The time is 60-90 minutes.

[0008] The oxide film growth process involves the workpiece reacting with electrolytic oxygen at the anode to generate alumina, while the simultaneous oxidation bath solution reacts with and dissolves the alumina. When the oxide film formation rate exceeds the dissolution rate, the oxide film thickness increases over time. This invention addresses the problem of long oxidation times by adding different additives to the traditional sulfuric acid anodizing bath solution to increase the oxide film formation rate while simultaneously reducing the oxide film dissolution rate.

[0009] A rapid film-forming process for hard anodizing includes conventional methods such as top hanging, degreasing, alkaline etching, film stripping, anodizing, sealing, and bottom hanging. The sealing tank contains sodium metasilicate as an additive at a concentration of 2-4 g / L. By using the sealing additive, the sealing time and temperature can be reduced, thereby lowering energy consumption. The sealing temperature is 85-95℃, and the sealing time is 20-40 minutes.

[0010] A process for hard anodizing film formation, the process comprising hanging, degreasing, alkaline etching, film stripping, anodizing, sealing, and hanging again, wherein the anodizing bath solution comprises sulfuric acid, aluminum sulfate octadecylhydrate, and glycolic acid solution, and the sealing bath solution comprises sodium metasilicate.

[0011] Preferably, the anodizing bath contains sulfuric acid at 140-180 g / L, aluminum sulfate octadecylhydrate at 48-120 g / L, 25-30% glycolic acid solution at 3-7 g / L, and sodium metasilicate in the sealing tank at 2-4 g / L.

[0012] Preferably, the anodizing temperature is -4 to 0℃; the current density is 1.5 to 2.5 A / dm³. 2 The sealing time is 60-90 minutes. The sealing temperature is 85-95℃, and the sealing time is 20-40 minutes.

[0013] Hard anodizing film formation process consumes a lot of energy, so it is necessary to control the time of the entire oxidation process. This invention reduces the oxidation process time, thereby reducing the final oxidation voltage, which in turn reduces the energy consumption and the cost of cooling the bath.

[0014] Compared with the prior art, the beneficial effects of the present invention are: by using anodizing formulation and / or combining it with sealing additives, the anodizing efficiency can be greatly improved, the process energy consumption can be reduced, the production cost can be reduced, and environmental protection, energy saving and efficiency can be achieved. Detailed Implementation

[0015] The present technical solution will be further described in detail below through specific embodiments. The raw materials used in the embodiments are all commercially available or prepared using conventional methods. The process method of the present technical solution is based on a conventional process with the addition of the required raw materials. However, it should be understood that the examples given are intended to help illustrate the method and beneficial effects of the present invention, and are not intended to limit the scope of protection of the present invention.

[0016] Example 1: A process for rapid film formation through hard anodizing includes conventional methods such as top hanging, degreasing, alkaline etching, film stripping, anodizing, sealing, and bottom hanging. 1. Hanging Select conductive fixtures (aluminum / titanium material) according to the size / shape of the workpiece to ensure tight contact between the workpiece and the fixture (avoid poor contact leading to localized lack of film); workpieces with deep holes / blind holes need to be sealed (to prevent subsequent bath solution residue).

[0017] Key considerations for compatibility: Hard anodized steel has a high current density, so it is necessary to ensure good conductivity at the clamping point to avoid overheating and burning.

[0018] 2. Degreasing: Removes surface impurities and improves the uniformity and adhesion of the oxide film. Bath solution composition: weakly alkaline degreasing solution to remove surface oil stains.

[0019] Process connection: After degreasing, a two-stage water wash is required, and the surface must be evenly moistened before proceeding to the alkaline etching process. 3. Alkaline Etching: Before anodizing aluminum and its alloys, the dense but uneven natural oxide film needs to be removed. An alkaline bath solution, primarily composed of NaOH (50 g / L), is used. The operating temperature is 50℃, and the time is 1 minute. Alkaline etching is simple to maintain, low in cost, and provides good etching results, easily removing machining streaks from the aluminum alloy surface.

[0020] 4. Peeling (brightening): Soak in 20%~30% HNO3 solution at room temperature to expose the crystalline layer on the surface, then wash with water until neutral.

[0021] 5. Anodizing (Hard) The workpiece, acting as the anode, is placed in an anodizing bath. The anodizing bath solution contains 160 g / L sulfuric acid, 100 g / L aluminum sulfate octahydrate, and 5 g / L 30% glycolic acid solution. The anodizing temperature is 0°C, and the current density is 2 A / dm³. 2 The time is 90 minutes, and direct current is applied to generate an oxide film on the metal surface.

[0022] 6. Sealing: Blocking the micropores of the oxide film, reducing porosity, and enhancing the corrosion resistance and surface smoothness of the film.

[0023] Procedure: Seal the hole with boiling water (100℃, 240 min), then wash and dry.

[0024] 7. Hanging down Procedure: Carefully remove the fixture to avoid scratching the membrane; perform local repairs on the fixture contact points (such as additional polishing), and then perform membrane performance testing (membrane thickness, salt spray test, hardness, and breakdown voltage).

[0025] Example 2 A process for rapid film formation through hard anodizing includes conventional methods such as top hanging, degreasing, alkaline etching, film stripping, anodizing, sealing, and bottom hanging. 1. Hanging Select conductive fixtures (aluminum / titanium material) according to the size / shape of the workpiece to ensure tight contact between the workpiece and the fixture (avoid poor contact leading to localized lack of film); workpieces with deep holes / blind holes need to be sealed (to prevent subsequent bath solution residue).

[0026] Key considerations for compatibility: Hard anodized steel has a high current density, so it is necessary to ensure good conductivity at the clamping point to avoid overheating and burning.

[0027] 2. Degreasing: Removes surface impurities and improves the uniformity and adhesion of the oxide film. Bath solution composition: weakly alkaline degreasing solution to remove surface oil stains. Process connection: After degreasing, it needs to be washed with water for two stages and the surface needs to be evenly moistened before it can enter the alkaline etching process.

[0028] 3. Alkaline Etching: Before anodizing aluminum and its alloys, the dense but uneven natural oxide film needs to be removed. An alkaline bath solution, primarily composed of NaOH (50 g / L), is used. The operating temperature is 50℃, and the time is 1 minute. Alkaline etching is simple to maintain, low in cost, and provides good etching results, easily removing machining streaks from the aluminum alloy surface.

[0029] 4. Peel off the film (light out) Procedure: Soak in 20%~30% HNO3 solution at room temperature until the surface crystallization layer is exposed, then wash with water until neutral.

[0030] 5. Anodizing (Hard) Operation: The workpiece is placed in an anodizing bath as the anode. The sulfuric acid concentration in the anodizing bath is 160 g / L, the anodizing temperature is 0°C, and the current density is 2 A / dm³. 2 The time is 180 minutes, and direct current is applied to generate an oxide film on the metal surface.

[0031] 6. Sealing: Blocking the micropores of the oxide film, reducing porosity, and enhancing the corrosion resistance and surface smoothness of the film.

[0032] Procedure: Add 3 g / L of sodium metasilicate to the hot water in the sealing tank, set the sealing temperature to 90℃, and seal for 30 minutes. Then rinse and dry.

[0033] 7. Hanging down Procedure: Carefully remove the fixture to avoid scratching the membrane; perform local repairs on the fixture contact points (such as additional polishing), and then perform membrane performance testing (membrane thickness, salt spray test, hardness, and breakdown voltage).

[0034] Example 3 A process for rapid film formation through hard anodizing includes conventional methods such as top hanging, degreasing, alkaline etching, film stripping, anodizing, sealing, and bottom hanging. 1. Hanging Select conductive fixtures (aluminum / titanium material) according to the size / shape of the workpiece to ensure tight contact between the workpiece and the fixture (avoid poor contact leading to localized lack of film); workpieces with deep holes / blind holes need to be sealed (to prevent subsequent bath solution residue).

[0035] Key considerations for compatibility: Hard anodized steel has a high current density, so it is necessary to ensure good conductivity at the clamping point to avoid overheating and burning.

[0036] 2. Degreasing: Removes surface impurities and improves the uniformity and adhesion of the oxide film. Bath solution composition: weakly alkaline degreasing solution to remove surface oil stains. Process connection: After degreasing, it needs to be washed with water for two stages and the surface needs to be evenly moistened before it can enter the alkaline etching process.

[0037] 3. Alkaline Etching: Before anodizing aluminum and its alloys, the dense but uneven natural oxide film needs to be removed. An alkaline bath solution, primarily composed of NaOH (50 g / L), is used. The operating temperature is 50℃, and the time is 1 minute. Alkaline etching is simple to maintain, low in cost, and provides good etching results, easily removing machining streaks from the aluminum alloy surface.

[0038] 4. Peel off the film (light out) Procedure: Soak in 20%~30% HNO3 solution at room temperature until the surface crystallization layer is exposed, then wash with water until neutral.

[0039] 5. Anodizing (Hard) The workpiece, acting as the anode, is placed in an anodizing bath. The anodizing bath solution contains 160 g / L sulfuric acid, 100 g / L aluminum sulfate octahydrate, and 5 g / L 30% glycolic acid solution. The anodizing temperature is 0°C, and the current density is 2 A / dm³. 2 The time is 90 minutes, and direct current is applied to generate an oxide film on the metal surface.

[0040] 6. Sealing: Blocking the micropores of the oxide film, reducing porosity, and enhancing the corrosion resistance and surface smoothness of the film.

[0041] Procedure: Add 3 g / L of sodium metasilicate to the hot water in the sealing tank, set the sealing temperature to 90℃, and seal for 30 minutes. Then rinse and dry.

[0042] 7. Hanging down Procedure: Carefully remove the fixture to avoid scratching the membrane; perform local repairs on the fixture contact points (such as additional polishing), and then perform membrane performance testing (membrane thickness, salt spray test, hardness, and breakdown voltage).

[0043] Example 4 A process for rapid film formation through hard anodizing includes conventional methods such as top hanging, degreasing, alkaline etching, film stripping, anodizing, sealing, and bottom hanging. 1. Hanging Select conductive fixtures (aluminum / titanium material) according to the size / shape of the workpiece to ensure tight contact between the workpiece and the fixture (avoid poor contact leading to localized lack of film); workpieces with deep holes / blind holes need to be sealed (to prevent subsequent bath solution residue).

[0044] Key considerations for compatibility: Hard anodized steel has a high current density, so it is necessary to ensure good conductivity at the clamping point to avoid overheating and burning.

[0045] 2. Degreasing: Removes surface impurities and improves the uniformity and adhesion of the oxide film. Bath solution composition: weakly alkaline degreasing solution to remove surface oil stains. Process connection: After degreasing, it needs to be washed with water for two stages and the surface needs to be evenly moistened before it can enter the alkaline etching process.

[0046] 3. Alkaline Etching: Before anodizing aluminum and its alloys, the dense but uneven natural oxide film needs to be removed. An alkaline bath solution, primarily composed of NaOH (50 g / L), is used. The operating temperature is 50℃, and the time is 1 minute. Alkaline etching is simple to maintain, low in cost, and provides good etching results, easily removing machining streaks from the aluminum alloy surface.

[0047] 4. Peel off the film (light out) Procedure: Soak in 20%~30% HNO3 solution at room temperature until the surface crystallization layer is exposed, then wash with water until neutral.

[0048] 5. Anodizing (Hard) The workpiece, acting as the anode, is placed in an anodizing bath. The anodizing bath solution contains 160 g / L sulfuric acid, 100 g / L aluminum sulfate octahydrate, and 7 g / L 25% glycolic acid solution. The anodizing temperature is 0°C, and the current density is 2.5 A / dm³. 2 The time is 90 minutes, and direct current is applied to generate an oxide film on the metal surface.

[0049] 6. Sealing: Blocking the micropores of the oxide film, reducing porosity, and enhancing the corrosion resistance and surface smoothness of the film.

[0050] Procedure: Add 4 g / L of sodium metasilicate to the hot water in the sealing tank, set the sealing temperature to 85℃, and seal for 30 minutes. Then rinse and dry.

[0051] 7. Hanging down Procedure: Carefully remove the fixture to avoid scratching the membrane; perform local repairs on the fixture contact points (such as additional polishing), and then perform membrane performance testing (membrane thickness, salt spray test, hardness, and breakdown voltage).

[0052] Example 5 A process for rapid film formation through hard anodizing includes conventional methods such as top hanging, degreasing, alkaline etching, film stripping, anodizing, sealing, and bottom hanging. 1. Hanging Select conductive fixtures (aluminum / titanium material) according to the size / shape of the workpiece to ensure tight contact between the workpiece and the fixture (avoid poor contact leading to localized lack of film); workpieces with deep holes / blind holes need to be sealed (to prevent subsequent bath solution residue).

[0053] Key considerations for compatibility: Hard anodized steel has a high current density, so it is necessary to ensure good conductivity at the clamping point to avoid overheating and burning.

[0054] 2. Degreasing: Removes surface impurities and improves the uniformity and adhesion of the oxide film. Bath solution composition: weakly alkaline degreasing solution to remove surface oil stains. Process connection: After degreasing, it needs to be washed with water for two stages and the surface needs to be evenly moistened before it can enter the alkaline etching process.

[0055] 3. Alkaline Etching: Before anodizing aluminum and its alloys, the dense but uneven natural oxide film needs to be removed. An alkaline bath solution, primarily composed of NaOH (50 g / L), is used. The operating temperature is 50℃, and the time is 1 minute. Alkaline etching is simple to maintain, low in cost, and provides good etching results, easily removing machining streaks from the aluminum alloy surface.

[0056] 4. Peel off the film (light out) Procedure: Soak in 20%~30% HNO3 solution at room temperature until the surface crystallization layer is exposed, then wash with water until neutral.

[0057] 5. Anodizing (Hard) The workpiece, acting as the anode, is placed in an anodizing bath. The anodizing bath solution contains 150 g / L sulfuric acid, 110 g / L aluminum sulfate octahydrate, and 5 g / L 25% glycolic acid solution. The anodizing temperature is 0°C, and the current density is 1.5 A / dm³. 2 The time is 90 minutes, and direct current is applied to generate an oxide film on the metal surface.

[0058] 6. Sealing: Blocking the micropores of the oxide film, reducing porosity, and enhancing the corrosion resistance and surface smoothness of the film.

[0059] Procedure: Add 4 g / L of sodium metasilicate to the hot water in the sealing tank, set the sealing temperature to 85℃, and seal for 40 minutes. Then rinse and dry.

[0060] 7. Hanging down Procedure: Carefully remove the fixture to avoid scratching the membrane; perform local repairs on the fixture contact points (such as additional polishing), and then perform membrane performance testing (membrane thickness, salt spray test, hardness, and breakdown voltage).

[0061] Example 6 A process for rapid film formation through hard anodizing includes conventional methods such as top hanging, degreasing, alkaline etching, film stripping, anodizing, sealing, and bottom hanging. 1. Hanging Select conductive fixtures (aluminum / titanium material) according to the size / shape of the workpiece to ensure tight contact between the workpiece and the fixture (avoid poor contact leading to localized lack of film); workpieces with deep holes / blind holes need to be sealed (to prevent subsequent bath solution residue).

[0062] Key considerations for compatibility: Hard anodized steel has a high current density, so it is necessary to ensure good conductivity at the clamping point to avoid overheating and burning.

[0063] 2. Degreasing: Removes surface impurities and improves the uniformity and adhesion of the oxide film. Bath solution composition: weakly alkaline degreasing solution to remove surface oil stains. Process connection: After degreasing, it needs to be washed with water for two stages and the surface needs to be evenly moistened before it can enter the alkaline etching process.

[0064] 3. Alkaline Etching: Before anodizing aluminum and its alloys, the dense but uneven natural oxide film needs to be removed. An alkaline bath solution, primarily composed of NaOH (50 g / L), is used. The operating temperature is 50℃, and the time is 1 minute. Alkaline etching is simple to maintain, low in cost, and provides good etching results, easily removing machining streaks from the aluminum alloy surface.

[0065] 4. Peel off the film (light out) Procedure: Soak in 20%~30% HNO3 solution at room temperature until the surface crystallization layer is exposed, then wash with water until neutral.

[0066] 5. Anodizing (Hard) The workpiece, acting as the anode, is placed in an anodizing bath. The anodizing bath solution contains 180 g / L sulfuric acid, 60 g / L aluminum sulfate octahydrate, and 4 g / L 30% glycolic acid solution. The anodizing temperature is -2℃, and the current density is 2.5 A / dm³. 2 The time is 70 minutes, and direct current is applied to generate an oxide film on the metal surface.

[0067] 6. Sealing: Blocking the micropores of the oxide film, reducing porosity, and enhancing the corrosion resistance and surface smoothness of the film.

[0068] Procedure: Add 4 g / L of sodium metasilicate to the hot water in the sealing tank, set the sealing temperature to 80℃, and seal for 25 minutes. Then rinse and dry.

[0069] 7. Hanging down Procedure: Carefully remove the fixture to avoid scratching the membrane; perform local repairs on the fixture contact points (such as additional polishing), and then perform membrane performance testing (membrane thickness, salt spray test, hardness, and breakdown voltage).

[0070] Example 7 A process for rapid film formation through hard anodizing includes conventional methods such as top hanging, degreasing, alkaline etching, film stripping, anodizing, sealing, and bottom hanging. 1. Hanging Select conductive fixtures (aluminum / titanium material) according to the size / shape of the workpiece to ensure tight contact between the workpiece and the fixture (avoid poor contact leading to localized lack of film); workpieces with deep holes / blind holes need to be sealed (to prevent subsequent bath solution residue).

[0071] Key considerations for compatibility: Hard anodized steel has a high current density, so it is necessary to ensure good conductivity at the clamping point to avoid overheating and burning.

[0072] 2. Degreasing: Removes surface impurities and improves the uniformity and adhesion of the oxide film. Bath solution composition: weakly alkaline degreasing solution to remove surface oil stains. Process connection: After degreasing, it needs to be washed with water for two stages and the surface needs to be evenly moistened before it can enter the alkaline etching process.

[0073] 3. Alkaline Etching: Before anodizing aluminum and its alloys, the dense but uneven natural oxide film needs to be removed. An alkaline bath solution, primarily composed of NaOH (50 g / L), is used. The operating temperature is 50℃, and the time is 1 minute. Alkaline etching is simple to maintain, low in cost, and provides good etching results, easily removing machining streaks from the aluminum alloy surface.

[0074] 4. Peel off the film (light out) Procedure: Soak in 20%~30% HNO3 solution at room temperature until the surface crystallization layer is exposed, then wash with water until neutral.

[0075] 5. Anodizing (Hard) The workpiece, acting as the anode, is placed in an anodizing bath. The anodizing bath solution contains 180 g / L sulfuric acid, 80 g / L aluminum sulfate octahydrate, and 6 g / L 30% glycolic acid solution. The anodizing temperature is -1℃, and the current density is 2.5 A / dm³. 2 The time is 85 minutes, and direct current is applied to generate an oxide film on the metal surface.

[0076] 6. Sealing: Blocking the micropores of the oxide film, reducing porosity, and enhancing the corrosion resistance and surface smoothness of the film.

[0077] Procedure: Add 2 g / L of sodium metasilicate to the hot water in the sealing tank, set the sealing temperature to 85℃, and seal for 40 minutes. Then rinse and dry.

[0078] 7. Hanging down Procedure: Carefully remove the fixture to avoid scratching the membrane; perform local repairs on the fixture contact points (such as additional polishing), and then perform membrane performance testing (membrane thickness, salt spray test, hardness, and breakdown voltage).

[0079] Comparative Example 1 (Standardized Operating Procedures for Anodizing Process) A process for rapid film formation through hard anodizing includes conventional methods such as top hanging, degreasing, alkaline etching, film stripping, anodizing, sealing, and bottom hanging. 1. Hanging Select conductive fixtures (aluminum / titanium material) according to the size / shape of the workpiece to ensure tight contact between the workpiece and the fixture (avoid poor contact leading to localized lack of film); workpieces with deep holes / blind holes need to be sealed (to prevent subsequent bath solution residue).

[0080] Key considerations for compatibility: Hard anodized steel has a high current density, so it is necessary to ensure good conductivity at the clamping point to avoid overheating and burning.

[0081] 2. Degreasing: Removes surface impurities and improves the uniformity and adhesion of the oxide film. Bath solution composition: weakly alkaline degreasing solution to remove surface oil stains. Process connection: After degreasing, it needs to be washed with water for two stages and the surface needs to be evenly moistened before it can enter the alkaline etching process. 3. Alkaline Etching: Before anodizing aluminum and its alloys, the dense but uneven natural oxide film needs to be removed. An alkaline bath solution, primarily composed of NaOH (50 g / L), is used. The operating temperature is 50℃, and the time is 1 minute. Alkaline etching is simple to maintain, low in cost, and provides good etching results, easily removing machining streaks from the aluminum alloy surface.

[0082] 4. Peel off the film (light out) Procedure: Soak in 25% HNO3 solution at room temperature until the surface crystallization layer is exposed, then wash with water until neutral.

[0083] 5. Anodizing (Hard) Operation: The workpiece is placed in an anodizing bath as the anode. The sulfuric acid concentration in the anodizing bath is 160 g / L, the anodizing temperature is 0°C, and the current density is 2 A / dm³. 2 The time is 180 minutes, and direct current is applied to generate an oxide film on the metal surface.

[0084] 6. Sealing: Blocking the micropores of the oxide film, reducing porosity, and enhancing the corrosion resistance and surface smoothness of the film.

[0085] Procedure: Seal the hole with boiling water (95~100℃, 240min), then wash and dry.

[0086] 7. Hanging down Procedure: Carefully remove the fixture to avoid scratching the membrane; perform local repairs on the fixture contact points (such as additional polishing), and then perform membrane performance testing (membrane thickness, salt spray test, hardness, and breakdown voltage).

[0087] Test case The performance of samples 1-3 prepared according to the processes of Examples 1-3 was tested and compared with that of the sample of Comparative Example 1 prepared according to the conventional process. The results are shown in Table 1: Table 1: Table 1 shows that the performance of samples produced by the new process is basically the same as that of samples produced by the conventional process. However, the new process reduces the oxidation process and sealing time, improves anodizing efficiency, reduces process energy consumption, and lowers production costs, achieving both environmental protection and energy conservation while improving efficiency.

[0088] The above are merely preferred embodiments of the present invention and do not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made using the present invention specification, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A process for hard anodizing film formation, the process comprising: top hanging - degreasing - alkaline etching - film stripping - anodizing - sealing - bottom hanging, characterized in that, The anodizing bath solution includes sulfuric acid, aluminum sulfate octadecylhydrate, and 25-30% glycolic acid solution.

2. The process for hard anodizing film formation according to claim 1, characterized in that, The anodizing bath solution contains sulfuric acid: 140-180 g / L, aluminum sulfate octadecylhydrate: 48-120 g / L, and 25-30% glycolic acid solution: 3-7 g / L.

3. The process for hard anodizing film formation according to claim 1 or 2, characterized in that, Anodizing at temperatures ranging from -4 to 0°C; current density of 1.5-2.5 A / dm³. 2 The time is 60-90 minutes.

4. A process for hard anodizing film formation, characterized in that, The process includes top hanging, degreasing, alkaline etching, film stripping, anodizing, sealing, and bottom hanging, characterized in that the sealing bath solution includes sodium metasilicate.

5. The process for hard anodizing film formation according to claim 4, characterized in that, The amount of sodium metasilicate added to the sealing groove is 2-4 g / L.

6. The process for hard anodizing film formation according to claim 4 or 5, characterized in that, The sealing temperature is 85-95℃, and the sealing time is 20-40 minutes.

7. A process for hard anodizing film formation, the process comprising: top hanging - degreasing - alkaline etching - film stripping - anodizing - sealing - bottom hanging, characterized in that, The anodizing bath solution includes sulfuric acid, aluminum sulfate octadecylhydrate, and glycolic acid solution, while the sealing bath solution includes sodium metasilicate.

8. The process for hard anodizing film formation according to claim 7, characterized in that, The anodizing bath solution contains sulfuric acid at 140-180 g / L, aluminum sulfate octadecylhydrate at 48-120 g / L, 25-30% glycolic acid solution at 3-7 g / L, and sodium metasilicate added to the sealing tank at 2-4 g / L.

9. The process for hard anodizing film formation according to claim 7 or 8, characterized in that, The anodizing temperature is -4 to 0℃; the current density is 1.5 to 2.5 A / dm³. 2 The time is 60-90 minutes.

10. The process for hard anodizing film formation according to claim 7 or 8, characterized in that, The sealing temperature is 85-95℃, and the sealing time is 20-40 minutes.

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