Surface treatment method of CVD (Chemical Vapor Deposition) gas diffuser

Abstract

The invention provides a surface treatment method of a CVD (chemical vapor deposition) gas diffuser. The surface treatment method comprises the following steps: S1, shielding; s2, washing with water after degreasing treatment; s3, washing after alkali etching, washing with water after acid pickling, and flushing; s4, anodic oxidation is conducted, oxidation liquid medicine comprises ammonium adipate accounting for 1%-15% of the volume of an anodic oxidation tank, an auxiliary agent accounting for 60%-90% of the volume of the anodic oxidation tank and the balance pure water, the auxiliary agent comprises diethylene glycol, the set voltage is 300-480 V, the climbing time is 1-10 min, the holding time is 3-10 min, and the temperature is 45-60 DEG C; s5, blow-drying after cleaning; and S6, placing in a high-temperature and high-pressure steam cavity for hydration reaction, setting the pressure to be 0.2-0.4 MPa, the temperature to be 100-170 DEG C, the humidity to be 50-100% RH and the reaction time to be 1-2 hours, taking out after the reaction is finished, and cooling to room temperature. The average corrosion resistance time of the oxidation film obtained through the method in a hydrochloric acid aqueous solution with the mass fraction of 5% reaches 2600 seconds or above, and in addition, the corrosion resistance improvement rate which can be achieved in the prior art can be broken through through the arrangement of hydration reaction conditions.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of surface treatment of aluminum alloy profiles, in particular to a surface treatment method of a CVD gas diffuser. BACKGROUND

[0002] The CVD gas diffuser is one of the core components in the CVD equipment, the CVD gas diffuser is an aluminum flat plate structure, and gas diffusion holes are uniformly distributed on the surface, which functions to uniformly disperse the gas entering the reaction chamber to the substrate surface to ensure that the gas forms a stable laminar flow in the substrate area. Since the gas introduced into the reaction chamber is usually a corrosive gas, the aluminum flat plate constituting the CVD gas diffuser is usually surface treated to improve the corrosion resistance of the aluminum flat plate. In the organic light-emitting semiconductor manufacturing industry, the surface treatment process of the CVD gas diffuser is usually to form a thin and dense oxide film on the surface of the gas diffuser in a specific anodizing solution by applying an external voltage, thereby improving its corrosion resistance. However, the anodizing solution in the prior art is usually based on sulfuric acid or oxalic acid, and the corrosion resistance of the oxide film obtained from the acid system is poor. In addition, the oxide film obtained by anodizing is usually immersed in boiling water for hydration reaction under normal pressure to further improve the corrosion resistance. However, such hydration method has the problem of low corrosion resistance improvement degree, and the corrosion resistance of the oxide film after hydration treatment is usually improved by about 30% compared with the oxide film without hydration treatment, which cannot achieve the effect of doubling the corrosion resistance. SUMMARY

[0003] In order to overcome the shortcomings of the prior art, the purpose of the present application is to provide a surface treatment method of a CVD gas diffuser, which can improve the corrosion resistance of the oxide film obtained by anodizing by using the oxidation solution in the surface treatment method and the specific oxidation parameters and hydration reaction conditions, so as to break through the corrosion resistance improvement rate that can be achieved by the prior art.

[0004] To solve the above problems, the technical scheme adopted by the present application is as follows: A surface treatment method of a CVD gas diffuser, comprising the following steps: S1, shielding the non-lifting screw holes and non-anodizing areas of the CVD gas diffuser made of aluminum, installing titanium screws in the lifting screw holes, and lifting the CVD gas diffuser after being hung with titanium hangers; S2, after the CVD gas diffuser is subjected to degreasing treatment, it is washed with water to remove residual degreasing solution; S3. After alkaline etching of the CVD gas diffuser, it is washed with water to remove residual alkaline etching solution. Then, the CVD gas diffuser is acid-washed. After acid washing, it is transferred to a water washing tank to wash with water to remove acid washing solution. Finally, the surface is rinsed with a high-pressure water gun to ensure that there is no chemical residue. S4. Transfer the CVD gas diffuser to the anodizing tank for anodizing. The anodizing solution includes ammonium adipate accounting for 1% to 15% of the volume of the anodizing tank, an additive accounting for 60% to 90% of the volume of the anodizing tank, and the remainder is pure water. The additive includes diethylene glycol. The parameters for anodizing are set as follows: voltage is 300 to 480V, ramp-up time is 1 to 10 minutes, holding time is 3 to 10 minutes, and temperature is 45 to 60℃. S5. Use a high-pressure water gun to rinse the surface of the CVD gas diffuser to ensure that there is no oxidizing agent residue. Then rinse it in pure water. After rinsing, dry the CVD gas diffuser with clean compressed air and remove the titanium hangers, titanium screws and shielding materials. S6. Place the CVD gas diffuser in a high-temperature, high-pressure steam chamber for hydration reaction. The pressure is set to 0.2~0.4MPa, the temperature to 100~170℃, the humidity to 50~100%RH, and the reaction time to 1~2h. After the reaction is complete, remove the diffuser and cool it to room temperature to obtain the final product.

[0005] In some possible implementations, the degreasing agent concentration in the degreasing solution used in step S2 is 30~40 g / L, the degreasing temperature is 40~50℃, and the treatment time is 5~10 min.

[0006] In some possible implementations, the alkaline etching solution used in step S3 is an aqueous sodium hydroxide solution with a sodium hydroxide concentration of 30-40 g / L, and the alkaline etching temperature is 40-50°C and the etching time is 30-90 s.

[0007] In some possible implementations, the acid solution used for pickling in step S3 is an aqueous solution of nitric acid with a mass fraction of 30% to 40%, and the pickling temperature is room temperature and the processing time is 3 to 5 minutes.

[0008] In some possible implementations, the preparation method of the oxidizing solution in step S4 is as follows: add 1% to 15% of the volume of ammonium adipate and 60% to 90% of the volume of the auxiliary agent to the cleaned anodizing tank, add pure water with a conductivity of less than or equal to 1µS / cm until the working liquid level is reached, and continue to aerate and stir until fully dissolved.

[0009] In some possible implementations, the adjuvant further includes triethanolamine and sodium phosphate, wherein the volume ratio of the diethylene glycol to the triethanolamine to the sodium phosphate is 8:1-1.8:0.2-1.

[0010] In some possible implementations, during the preparation of the oxidizing solution, after adding the ammonium adipic acid, the diethylene glycol, the sodium phosphate, and the triethanolamine are added sequentially.

[0011] In some possible implementations, the flushing pressure of the high-pressure water gun in steps S3 and S5 is greater than or equal to 300 kg.

[0012] In some possible implementations, in step S1, acid and alkali resistant rubber plugs are used to cover the non-lifting screw holes of the CVD gas diffuser, and acid and alkali resistant tape and acid and alkali resistant resin are used to cover the non-anodized areas of the CVD gas diffuser.

[0013] In some possible implementations, in step S6, the temperature is 150~170°C and the humidity is 60~90%RH.

[0014] Compared with the prior art, the beneficial effects of the present invention are as follows: In this application, anodizing of an aluminum CVD gas diffuser is performed using a specific oxidizing solution and specific oxidation parameters, followed by a hydration reaction under specific conditions. This results in an oxide film obtained after anodizing exhibiting an average corrosion resistance time of over 2600 seconds in a 5% hydrochloric acid aqueous solution. Furthermore, the hydration reaction conditions provided in this application ensure that the average corrosion resistance time of the hydrated oxide film is at least three times that of the unhydrated oxide film. Therefore, the surface treatment method provided in this application can significantly improve the corrosion resistance of the oxide film, thereby surpassing the corrosion resistance improvement rate achievable with existing technologies.

[0015] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments. Attached Figure Description

[0016] Figure 1 A schematic flowchart of a surface treatment method provided in an embodiment of this application; Figure 2 This is a SEM image of the oxide film prepared in Example 1 of the present invention; Figure 3 This is a SEM image of the surface of the CVD gas diffuser prepared in Example 1 of the present invention. Detailed Implementation

[0017] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0018] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0019] The following describes some embodiments of the present invention in detail. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0020] One embodiment of this application provides a surface treatment method for a CVD gas diffuser, referring to... Figure 1 The surface treatment method includes the following steps: Step S1: Cover the non-lifting screw holes and non-anodized areas of the aluminum CVD gas diffuser, install titanium screws in the lifting screw holes, and then lift the CVD gas diffuser using titanium hangers.

[0021] In some embodiments, acid and alkali resistant rubber plugs are used to cover the non-lifting screw holes of the CVD gas diffuser, and acid and alkali resistant tape and acid and alkali resistant resin are used to cover the non-anodized areas of the CVD gas diffuser.

[0022] Step S2: After degreasing the CVD gas diffuser, it is washed with water to remove residual degreasing solution. Specifically, the CVD gas diffuser is suspended in a degreasing tank (containing degreasing solution) for degreasing treatment to remove processing grease from the surface of the CVD gas diffuser. After degreasing, the CVD gas diffuser is suspended in a water washing tank for washing to remove residual degreasing solution. For example, the degreasing solution can be an aqueous solution, and the degreasing agent in the degreasing solution can include one of sodium carbonate, sodium silicate, or sodium phosphate.

[0023] In some embodiments, in this step, the concentration of the degreasing agent in the degreasing solution used for degreasing is 30~40 g / L, the degreasing temperature is 40~50℃, and the treatment time is 5~10 min. The appropriate combination of degreasing parameters helps to improve degreasing efficiency.

[0024] Step S3: After alkaline etching, the CVD gas diffuser is rinsed with water to remove residual alkaline etching solution. Then, the CVD gas diffuser is acid-washed, and after acid washing, it is transferred to a water washing tank for rinsing to remove the acid washing solution. Finally, the surface is rinsed with a high-pressure water gun to ensure no chemical residue remains. For example, the CVD gas diffuser can be suspended in an alkaline washing tank (containing alkaline etching solution) for alkaline etching to remove the natural oxide film on the diffuser surface. After alkaline etching, the CVD gas diffuser is suspended in a water washing tank for rinsing to remove residual alkaline etching solution. Then, the CVD gas diffuser is suspended in an acid washing tank for acid washing to remove residual components after alkaline washing. After acid washing, the CVD gas diffuser is transferred to a water washing tank for rinsing.

[0025] In some embodiments, in this step, the alkaline etching solution is an aqueous sodium hydroxide solution with a concentration of 30-40 g / L, the etching temperature is 40-50°C, and the etching time is 30-90 s. The etching parameters set in this application are beneficial to improving etching efficiency.

[0026] In some embodiments, in this step, the acid solution used for pickling is an aqueous solution of nitric acid, the mass fraction of nitric acid is 30%~40%, the pickling temperature is room temperature, and the processing time is 3~5 minutes.

[0027] In some embodiments, the rinsing pressure of the high-pressure water gun in this step is greater than or equal to 300 kg. Using a high-pressure water gun for rinsing helps to avoid adverse effects of the pre-anodizing solution on the subsequent anodizing process.

[0028] Step S4: Transfer the CVD gas diffuser to an anodizing tank for anodizing. The anodizing solution comprises 1%–15% ammonium adipate (by volume of the anodizing tank), 60%–90% an additive (by volume of the anodizing tank), and the remainder pure water. The additive includes diethylene glycol. In some embodiments, the additive is diethylene glycol, thus enabling the anodizing solution to achieve a good corrosion resistance enhancement effect through the simplest component combination, oxidation parameters, and hydration reaction under specific conditions in subsequent steps. The anodizing parameters are set as follows: voltage 300–480V, ramp-up time 1–10 min, holding time 3–10 min, and temperature 45–60℃.

[0029] In some embodiments, the preparation method of the oxidizing solution is as follows: add 1% to 15% of ammonium adipate and 60% to 90% of the additives to a cleaned anodizing tank, add pure water with a conductivity of less than or equal to 1µS / cm until the working liquid level is reached, and continuously aerate and stir until fully dissolved.

[0030] In some embodiments, the additive further includes triethanolamine and sodium phosphate, wherein the volume ratio of diethylene glycol to triethanolamine to sodium phosphate is 8:1-1.8:0.2-1. Further expanding the composition of the additive to achieve synergistic effects between the components is beneficial for further improving the corrosion resistance of the oxide film. In addition, the optimized oxidation solution of this application includes multiple components capable of forming intermolecular hydrogen bonds and complexing with aluminum. Therefore, the ratio of components is set considering the influence of the formed intermolecular hydrogen bond network on viscosity, ion transport, and participation in aluminum ion complexation, thereby reducing oxide film dissolution. The synergistic effect between salts and the interaction of intermolecular hydrogen bonds may affect ion conduction, thus affecting the properties of the oxide film.

[0031] In some embodiments, during the preparation of the oxidizing solution, after adding the ammonium adipic acid, the diethylene glycol, the sodium phosphate, and the triethanolamine are added in sequence, which helps to ensure the synergistic effect between the components.

[0032] Step S5: Rinse the surface of the CVD gas diffuser with a high-pressure water gun to ensure no oxidizing agent residue remains, then rinse it in pure water. For example, it can be soaked in pure water for 3-5 minutes. After cleaning, dry the CVD gas diffuser with filtered clean compressed air that is free of oil and water. Then remove the titanium hangers, titanium screws, and shielding materials, including acid and alkali resistant rubber plugs, acid and alkali resistant tape, and acid and alkali resistant resin.

[0033] In some embodiments, the flushing pressure of the high-pressure water gun in this step is greater than or equal to 300 kg.

[0034] Step S6: Place the CVD gas diffuser in a high-temperature, high-pressure steam chamber for hydration reaction. The pressure is set to 0.2~0.4MPa, the temperature to 100~170℃, the humidity to 50~100%RH, and the reaction time to 1~2h. After the reaction is complete, remove the diffuser and cool it to room temperature to obtain the final product.

[0035] In some embodiments, the temperature in this step is 150~170°C and the humidity is 60~90%RH. The selection of humidity and temperature is beneficial to further improve the corrosion resistance of the oxide film and the corrosion resistance improvement rate.

[0036] In this application, anodizing of an aluminum CVD gas diffuser is performed using a specific oxidizing solution and specific oxidation parameters, followed by a hydration reaction under specific conditions. This results in an oxide film obtained after anodizing exhibiting an average corrosion resistance time of over 2600 seconds in a 5% hydrochloric acid aqueous solution. Furthermore, the hydration reaction conditions provided in this application ensure that the average corrosion resistance time of the hydrated oxide film is at least three times that of the unhydrated oxide film. Therefore, the surface treatment method provided in this application can significantly improve the corrosion resistance of the oxide film, thereby surpassing the corrosion resistance improvement rate achievable with existing technologies.

[0037] The following detailed examples illustrate this.

[0038] Example 1 A surface treatment method for a CVD gas diffuser includes the following steps: Step S1: Use acid and alkali resistant rubber plugs to cover the non-lifting screw holes of the aluminum CVD gas diffuser, use acid and alkali resistant tape and acid and alkali resistant resin to cover the non-anodized areas of the CVD gas diffuser, install titanium screws in the lifting screw holes, and lift the CVD gas diffuser after mounting with titanium hangers.

[0039] Step S2: The CVD gas diffuser is suspended in the degreasing tank for degreasing treatment to remove the processing grease on the surface of the CVD gas diffuser. The degreasing agent concentration in the degreasing solution (sodium carbonate aqueous solution) used for degreasing treatment is 35g / L, the degreasing temperature is 45℃, and the treatment time is 5min. After degreasing, the CVD gas diffuser is suspended in the water washing tank for water washing to remove the residual degreasing solution. Step S3: The CVD gas diffuser is suspended in an alkaline etching tank to remove the natural oxide film on its surface. The alkaline etching solution is an aqueous sodium hydroxide solution with a sodium hydroxide concentration of 30 g / L. The alkaline etching temperature is 50°C and the soaking time is 30 seconds. After alkaline etching, the CVD gas diffuser is suspended in a water washing tank to remove residual alkaline etching solution. Then, the etched CVD gas diffuser is suspended in an acid washing tank to remove residual components after alkaline washing. The acid solution is an aqueous nitric acid solution with a nitric acid mass fraction of 35%. The acid washing temperature is room temperature and the treatment time is 5 minutes. After acid washing, the CVD gas diffuser is transferred to a water washing tank to wash away the acid solution. Finally, the radiator surface is rinsed with a high-pressure water gun with a rinsing pressure greater than or equal to 300 kg to ensure no chemical residue remains.

[0040] Step S4: Transfer the CVD gas diffuser to the anodizing tank for anodizing. The anodizing solution includes ammonium adipate accounting for 8% of the volume of the anodizing tank, diethylene glycol (auxiliary agent) accounting for 70% of the volume of the anodizing tank, and the remainder is pure water.

[0041] The preparation method of the oxidizing solution is as follows: Add ammonium adipate and diethylene glycol in the above proportion to a cleaned anodizing tank, add pure water with a conductivity of less than or equal to 1µS / cm until the working liquid level is reached, and continuously aerate and stir until fully dissolved.

[0042] The parameters for anodizing are set as follows: voltage 480V, ramp time 1 min, holding time 10 min, and temperature 60℃.

[0043] like Figure 2 As shown, a dense and uniform oxide film is formed on the surface of the CVD gas diffuser after step S4.

[0044] S5. Use a high-pressure water gun with a rinsing pressure of 300 kg or more to rinse the surface of the CVD gas diffuser to ensure that there is no oxidizing agent residue. Then immerse it in pure water for 5 minutes. After rinsing, dry the CVD gas diffuser with oil-free, water-free, filtered clean compressed air. Then remove the titanium hangers, titanium screws, and shielding materials (acid and alkali resistant rubber plugs, acid and alkali resistant tapes, and acid and alkali resistant resins).

[0045] S6. Place the CVD gas diffuser in a high-temperature, high-pressure steam chamber for hydration reaction. The pressure is set to 0.2 MPa, the temperature to 150°C, the humidity to 60% RH, and the reaction time to 1 hour. After the reaction is complete, remove the diffuser and cool it to room temperature to obtain the final product.

[0046] Depend on Figure 3 It can be seen that after the hydration reaction, the CVD gas diffuser of Example 1 has a hydration film covering the non-porous oxide film, which protects the non-porous oxide film and further improves its corrosion resistance.

[0047] Example 2 This embodiment provides a surface treatment method for a CVD gas diffuser. The difference between this embodiment and Embodiment 1 is that the voltage set in step S4 is 350V.

[0048] Comparative Example 1 This comparative example provides a surface treatment method for a CVD gas diffuser. The difference between this comparative example and Example 1 is that step S6 is not performed.

[0049] Comparative Example 2 This comparative example provides a surface treatment method for a CVD gas diffuser. The difference between this comparative example and Example 1 is that the oxidizing solution in step S4 consists of ammonium adipate accounting for 4% of the volume of the anodic oxidation tank and diethylene glycol accounting for 96% of the volume of the anodic oxidation tank. It can be seen that the oxidizing solution in this comparative example lacks water.

[0050] Example 3 This comparative example provides a surface treatment method for a CVD gas diffuser. The difference between this comparative example and Example 1 is that the humidity in step S6 is 100%RH.

[0051] Comparative Example 3 This comparative example provides a surface treatment method for a CVD gas diffuser. The difference between this comparative example and Example 1 is that the voltage and temperature of the anodic oxidation reaction in step S4 are set to 150V and 25℃.

[0052] Comparative Example 4 This comparative example provides a surface treatment method for a CVD gas diffuser. The difference between this comparative example and Comparative Example 3 is that the oxidizing solution in step S4 is 120 g / L sulfuric acid.

[0053] Example 4 A surface treatment method for a CVD gas diffuser includes the following steps: Step S1: Use acid and alkali resistant rubber plugs to cover the non-lifting screw holes of the aluminum CVD gas diffuser, use acid and alkali resistant tape and acid and alkali resistant resin to cover the non-anodized areas of the CVD gas diffuser, install titanium screws in the lifting screw holes, and lift the CVD gas diffuser after mounting with titanium hangers.

[0054] Step S2: The CVD gas diffuser is suspended in the degreasing tank for degreasing treatment to remove the processing grease on the surface of the CVD gas diffuser. The degreasing agent concentration in the degreasing solution (sodium carbonate aqueous solution) used for degreasing treatment is 40g / L, the degreasing temperature is 40℃, and the treatment time is 10min. After degreasing, the CVD gas diffuser is suspended in the water washing tank for water washing to remove the residual degreasing solution. Step S3: The CVD gas diffuser is suspended in an alkaline etching tank to remove the natural oxide film on its surface. The alkaline etching solution is an aqueous sodium hydroxide solution with a sodium hydroxide concentration of 40 g / L. The alkaline etching temperature is 40°C and the soaking time is 90 s. After alkaline etching, the CVD gas diffuser is suspended in a water washing tank to remove residual alkaline etching solution. Then, the etched CVD gas diffuser is suspended in an acid washing tank to remove residual components after alkaline washing. The acid washing solution is an aqueous nitric acid solution with a nitric acid mass fraction of 40%. The acid washing temperature is room temperature and the treatment time is 3 min. After acid washing, the CVD gas diffuser is transferred to a water washing tank to wash away the acid washing solution. Finally, the radiator surface is rinsed with a high-pressure water gun with a rinsing pressure greater than or equal to 300 kg to ensure that no acid residue remains.

[0055] Step S4: Transfer the CVD gas diffuser to the anodizing tank for anodizing. The anodizing solution includes ammonium adipate accounting for 10% of the volume of the anodizing tank, diethylene glycol (auxiliary agent) accounting for 60% of the volume of the anodizing tank, and the remainder is pure water.

[0056] The preparation method of the oxidizing solution is as follows: Add ammonium adipate and diethylene glycol in the above proportion to a cleaned anodizing tank, add pure water with a conductivity of less than or equal to 1µS / cm until the working liquid level is reached, and continuously aerate and stir until fully dissolved.

[0057] The parameters for anodizing are set as follows: voltage 300V, ramp time 5 min, holding time 5 min, and temperature 45℃.

[0058] Step S5: Use a high-pressure water gun with a rinsing pressure of 300 kg or more to rinse the surface of the CVD gas diffuser to ensure that there is no oxidizing agent residue. Then, immerse it in pure water for 3 minutes. After rinsing, dry the CVD gas diffuser with oil-free, water-free, filtered clean compressed air. Then, remove the titanium hangers, titanium screws, and shielding materials (acid and alkali resistant rubber plugs, acid and alkali resistant tapes, and acid and alkali resistant resins).

[0059] Step S6: Place the CVD gas diffuser in a high-temperature, high-pressure steam chamber for hydration reaction. The pressure is set to 0.4 MPa, the temperature to 170°C, the humidity to 90% RH, and the reaction time to 2 hours. After the reaction is complete, remove the diffuser and cool it to room temperature to obtain the final product.

[0060] Example 5 A surface treatment method for a CVD gas diffuser includes the following steps: Step S1: Use acid and alkali resistant rubber plugs to cover the non-lifting screw holes of the aluminum CVD gas diffuser, use acid and alkali resistant tape and acid and alkali resistant resin to cover the non-anodized areas of the CVD gas diffuser, install titanium screws in the lifting screw holes, and lift the CVD gas diffuser after mounting with titanium hangers.

[0061] Step S2: The CVD gas diffuser is suspended in the degreasing tank for degreasing treatment to remove the processing grease on the surface of the CVD gas diffuser. The degreasing agent concentration of the degreasing solution (sodium carbonate aqueous solution) used for degreasing treatment is 30g / L, the degreasing temperature is 50℃, and the treatment time is 8min. After degreasing, the CVD gas diffuser is suspended in the water washing tank for water washing to remove the residual degreasing solution. Step S3: The CVD gas diffuser is suspended in an alkaline etching tank to remove the natural oxide film on its surface. The alkaline etching solution is an aqueous sodium hydroxide solution with a sodium hydroxide concentration of 35 g / L. The alkaline etching temperature is 45°C and the soaking time is 60 seconds. After alkaline etching, the CVD gas diffuser is suspended in a water washing tank to remove residual alkaline etching solution. Then, the etched CVD gas diffuser is suspended in an acid washing tank to remove residual components after alkaline washing. The acid washing solution is an aqueous nitric acid solution with a nitric acid mass fraction of 30%. The acid washing temperature is room temperature and the treatment time is 4 minutes. After acid washing, the CVD gas diffuser is transferred to a water washing tank to wash away the acid washing solution. Finally, the surface of the radiator is rinsed with a high-pressure water gun with a rinsing pressure greater than or equal to 300 kg to ensure that no acid residue remains.

[0062] Step S4: Transfer the CVD gas diffuser to the anodizing tank for anodizing. The anodizing solution includes ammonium adipate accounting for 15% of the volume of the anodizing tank, diethylene glycol (auxiliary agent) accounting for 70% of the volume of the anodizing tank, and the remainder is pure water.

[0063] The preparation method of the oxidizing solution is as follows: Add ammonium adipate and diethylene glycol in the above proportion to a cleaned anodizing tank, add pure water with a conductivity of less than or equal to 1µS / cm until the working liquid level is reached, and continue to aerate and stir until fully dissolved. The parameters for anodizing are set as follows: voltage 400V, ramp time 1 min, holding time 10 min, and temperature 55℃.

[0064] Step S5: Use a high-pressure water gun with a rinsing pressure of 300 kg or more to rinse the surface of the CVD gas diffuser to ensure that there is no oxidizing agent residue. Then, immerse it in pure water for 3 minutes. After rinsing, dry the CVD gas diffuser with oil-free, water-free, filtered clean compressed air. Then, remove the titanium hangers, titanium screws, and shielding materials (acid and alkali resistant rubber plugs, acid and alkali resistant tapes, and acid and alkali resistant resins).

[0065] Step S6: Place the CVD gas diffuser in a high-temperature, high-pressure steam chamber for hydration reaction. The pressure is set to 0.3 MPa, the temperature to 130°C, the humidity to 50% RH, and the reaction time to 1.5 h. After the reaction is complete, remove the diffuser and cool it to room temperature to obtain the final product.

[0066] Example 6 The difference between this embodiment and Embodiment 1 is that, in step S4, the oxidizing solution includes ammonium adipate accounting for 1% of the volume of the anodic oxidation tank, diethylene glycol accounting for 90% of the volume of the anodic oxidation tank, and the remainder being pure water. In the parameter settings for anodic oxidation, the ramp-up time is 10 min and the holding time is 3 min. In step S6, the pressure is set to 0.4 MPa, the temperature is 100℃, and the humidity is 50%RH.

[0067] Example 7 The difference between this embodiment and Embodiment 1 is that the oxidizing agent further includes triethanolamine and sodium phosphate, and the volume ratio of diethylene glycol:triethanolamine:sodium phosphate is 8:1.5:0.5. When preparing the oxidizing agent, after adding ammonium adipic acid, diethylene glycol, sodium phosphate, and triethanolamine are added sequentially, followed by adding pure water until the working liquid level is reached.

[0068] Example 8 The difference between this embodiment and Embodiment 2 is that the oxidizing agent in this embodiment further includes triethanolamine and sodium phosphate, and the volume ratio of diethylene glycol to triethanolamine to sodium phosphate is 8:1:1. When preparing the oxidizing agent, after adding ammonium adipic acid, diethylene glycol, sodium phosphate, and triethanolamine are added sequentially, followed by adding pure water until the working liquid level is reached.

[0069] Example 9 The difference between this embodiment and Embodiment 3 is that the oxidizing agent in this embodiment further includes triethanolamine and sodium phosphate, and the volume ratio of diethylene glycol:triethanolamine:sodium phosphate is 8:1.4:0.6. When preparing the oxidizing agent, after adding ammonium adipic acid, diethylene glycol, sodium phosphate, and triethanolamine are added sequentially, followed by adding pure water until the working liquid level is reached.

[0070] Example 10 The difference between this embodiment and Embodiment 4 is that the oxidizing agent in this embodiment further includes triethanolamine and sodium phosphate, and the volume ratio of diethylene glycol:triethanolamine:sodium phosphate is 8:1.8:0.2. When preparing the oxidizing agent, after adding ammonium adipic acid, diethylene glycol, sodium phosphate, and triethanolamine are added sequentially, followed by adding pure water until the working liquid level is reached.

[0071] Example 11 The difference between this embodiment and Embodiment 5 is that the oxidizing agent in this embodiment further includes triethanolamine and sodium phosphate, and the volume ratio of diethylene glycol:triethanolamine:sodium phosphate is 8:1.7:0.3. When preparing the oxidizing agent, after adding ammonium adipic acid, diethylene glycol, sodium phosphate, and triethanolamine are added sequentially, followed by adding pure water until the working liquid level is reached.

[0072] Example 12 The difference between this embodiment and Embodiment 6 is that the oxidizing agent in this embodiment further includes triethanolamine and sodium phosphate, and the volume ratio of diethylene glycol:triethanolamine:sodium phosphate is 8:1.3:0.7. When preparing the oxidizing agent, after adding ammonium adipic acid, diethylene glycol, sodium phosphate, and triethanolamine are added sequentially, followed by adding pure water until the working liquid level is reached.

[0073] Comparative Example 5 The difference between this embodiment and Embodiment 7 is that the volume ratio of the diethylene glycol: the triethanolamine: the sodium phosphate is 8:1.9:0.1.

[0074] Comparative Example 6 The difference between this embodiment and Embodiment 7 is that the volume ratio of the diethylene glycol:triethanolamine:sodium phosphate is 8:0.9:1.1.

[0075] Comparative Example 7 The difference between this embodiment and Embodiment 7 is that the oxidizing agent in the embodiment includes only triethanolamine, and the volume ratio of diethylene glycol to triethanolamine is 8:2.

[0076] Comparative Example 8 The difference between this embodiment and Embodiment 7 is that the oxidizing agent in this embodiment includes only sodium phosphate, and the volume ratio of diethylene glycol to sodium phosphate is 8:2.

[0077] Corrosion resistance test The corrosion resistance of the CVD gas diffusers obtained from the examples and comparative examples was tested using the following methods: In a test environment with a temperature of 20±2℃ and a humidity of 55±10%RH, the aluminum part to be tested was placed in a transparent container, and a 5% hydrochloric acid aqueous solution was added to the container. The oxide film on the surface of the aluminum part began to dissolve, and the hydrochloric acid reacted with the aluminum to produce hydrogen foam. The time from the start of immersion to the continuous production of foam was measured and recorded, and the process was repeated three times. The results are shown in Table 1. Table 1 records the corrosion resistance time at different test points of the same part and the average corrosion resistance time calculated based on different test sites.

[0078] Table 1. Corrosion resistance test results of Example 1 and Comparative Examples 1-6

[0079] Comparing the test results of Examples 1-6 and Comparative Examples 1-4, it can be seen that the oxide film obtained by the oxidizing solution treatment provided in this application has better corrosion resistance than the oxide film obtained by conventional sulfuric acid oxidizing solution treatment. Furthermore, the average corrosion resistance time of the oxide film obtained by the hydration reaction conditions provided in this application is at least three times that of the untreated oxide film. In addition, combining the test results of Examples 7 to 12, it was found that further improvements to the additives can also significantly improve the corrosion resistance of the oxide film. Furthermore, comparing the test results of Examples 7-12 and Comparative Examples 5-8, it can be seen that not all amounts of triethanolamine and sodium phosphate can promote or significantly promote the system composed of ammonium adipic acid, diethylene glycol, and water.

[0080] The above embodiments are merely preferred embodiments of the present invention and should not be construed as limiting the scope of protection of the present invention. Any non-substantial changes and substitutions made by those skilled in the art based on the present invention shall fall within the scope of protection claimed by the present invention.

Claims

1. A surface treatment method for a CVD gas diffuser, characterized by, The method comprises the following steps: S1, shielding the non-lifting screw hole and non-anodizing area of the CVD gas diffuser of the aluminum material, installing titanium screws in the lifting screw hole, and lifting the CVD gas diffuser after being hung with a titanium hanger; S2, after the CVD gas diffuser is subjected to degreasing treatment, it is washed with water to remove residual degreasing solution; S3, after the CVD gas diffuser is subjected to alkali etching, it is washed with water to remove residual alkali etching solution, then it is subjected to acid pickling, and after the acid pickling, it is transferred to a water washing tank for water washing to remove the acid pickling solution, and finally the surface is washed with a high-pressure water gun to ensure that there is no residual chemical solution; S4, the CVD gas diffuser is transferred to an anodizing tank for anodizing, wherein the anodizing chemical solution comprises 1%-15% ammonium adipate based on the volume of the anodizing tank, 60%-90% additives based on the volume of the anodizing tank, and the balance of pure water, the additives comprise diethylene glycol, and the parameters of anodizing are set as follows: the voltage is 300-480V, the ramp time is 1-10min, the holding time is 3-10min, and the temperature is 45-60℃; S5, the surface of the CVD gas diffuser is washed with a high-pressure water gun to ensure that there is no residual anodizing chemical solution, and then it is cleaned in pure water, after cleaning, the CVD gas diffuser is dried with clean compressed air, then the titanium hanger, titanium screws and shielding materials are removed; S6, the CVD gas diffuser is placed in a high-temperature and high-pressure steam cavity for hydration reaction, the pressure is set to 0.2-0.4MPa, the temperature is 100-170℃, the humidity is 50-100%RH, and the reaction time is 1-2h, after the reaction is completed, it is taken out and cooled to room temperature to obtain the product.

2. The surface treatment method according to claim 1, characterized by, In step S2, the degreasing agent in the degreasing solution used in the degreasing treatment has a concentration of 30-40g / L, the degreasing temperature is 40-50℃, and the treatment time is 5-10min.

3. The surface treatment method according to claim 1, characterized by, In step S3, the alkali etching solution is a sodium hydroxide aqueous solution, the concentration of sodium hydroxide is 30-40g / L, the temperature of alkali etching is 40-50℃, and the time is 30-90s.

4. The surface treatment method according to claim 1, characterized by, In step S3, the acid solution for acid pickling is a nitric acid aqueous solution, the mass fraction of nitric acid is 30%-40%, the temperature of acid pickling is room temperature, and the treatment time is 3-5min.

5. The surface treatment method according to claim 1, characterized by, In step S4, the preparation method of the anodizing chemical solution is as follows: 1%-15% ammonium adipate based on the volume of the anodizing tank and 60%-90% additives based on the volume of the anodizing tank are added to the cleaned anodizing tank, and pure water with an electrical conductivity of less than or equal to 1µS / cm is added until the working liquid level, and continuous aeration and stirring are carried out until complete dissolution.

6. The surface treatment method according to claim 5, wherein The additives further comprise triethanolamine and sodium phosphate, and the volume ratio of the diethylene glycol:the triethanolamine:the sodium phosphate is 8:1-1.8:0.2-1.

7. The surface treatment method according to claim 6, wherein In the preparation process of the anodizing chemical solution, the diethylene glycol, the sodium phosphate and the triethanolamine are sequentially added after the addition of the ammonium adipate.

8. The surface treatment method according to claim 1, characterized by, In steps S3 and S5, the washing pressure of the high-pressure water gun is greater than or equal to 300kg.

9. The surface treatment method according to claim 1, characterized by, In step S1, acid and alkali resistant rubber plugs are used to shield the non-lifting screw holes of the CVD gas diffuser, and acid and alkali resistant rubber belts and acid and alkali resistant resins are used to shield the non-anodized areas of the CVD gas diffuser.

10. The surface treatment method according to claim 1, characterized by, In step S6, the temperature is 150-170℃, and the humidity is 60-90%RH.

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