Removal method for immersion type pollutants of oxidation film

Abstract

The invention discloses a method for removing oxidation film immersion type pollutants. The method comprises a cleaning method for workpieces polluted by heavy oil contamination type pollutants and workpieces polluted by complex oil contamination and solid powder. For a workpiece polluted by complex oil stains and solid powder, a special emulsion is prepared by adopting a specific HLB (Hydrophile-Lipophile Balance) value, and different oil stains and solid powder are removed at the same time through the solubility of the emulsion on mixed oil stains, the solubilization of a surfactant and the emulsification and stripping effects of ultrasonic waves in an ultrasonic cleaning manner; the purpose of cleaning is achieved, and the maximum cleaning rate can reach 100%.

Description

Technical Field

[0001] The present invention belongs to the technical field of metal corrosion and protection, and particularly relates to a method for removing oxide film immersion type pollutants. Background Art

[0002] The film layer with a non-dense and mesoscopic-level microstructure on the surface, such as the anodic oxidation films of aluminum alloy and magnesium alloy and the micro-arc oxidation films of various metals, has a relatively high specific surface area and surface tension, resulting in good wettability to various external substances, and is extremely vulnerable to contamination during the processing. Once external pollutants penetrate into the structure of the film layer, it is difficult to remove them by non-destructive cleaning methods.

[0003] For the cleaning of the surface of oxide films during non-surface treatment processes, there has always been a lack of a standardized and effective broad-spectrum cleaning process. According to the manufacturing industry, pollutants, and pollution processes, each unit generally uses commonly available cleaning media in the pollution process, such as washing gasoline, anhydrous ethanol, acetone, etc., and uses traditional wiping, soaking, or ultrasonic cleaning methods. In essence, it is a degreasing method for cleaning. However, in fact, the pollutants introduced in different processing steps are very complex, and there are even cases where the pollutants introduced in different steps are mixed to form more difficult-to-remove mixed pollutants. Considering the characteristics of oxide films being easily contaminated and difficult to clean, once the surface of the oxide film is contaminated, it is difficult to remove, and finally, the pollutants can only be removed together with the film layer by chemical methods. The chemical method for removing the oxide film layer is highly corrosive to metal parts and causes significant dimensional changes, and it is even more difficult to protect locally for assembled parts.

[0004] For the mixed pollutants on complex surfaces, the main cleaning methods are still soaking and rinsing, and the cleaning agents used are mainly halogenated hydrocarbons and hydrocarbon-based cleaning agents. The pollutants are removed from the surface through the dissolution and scouring effects of the cleaning agents. For approximately solidified pollutants, ultrasonic cleaning methods are usually supplemented. Such process methods are usually effective for the pollution of simple surfaces, but for the aluminum alloy anodic oxidation film, especially the film layer with a relatively high porosity such as the sulfuric acid anodic oxidation film, since the pollutants have penetrated into the pore structure of the film layer, it is very difficult to remove the pollution without sufficient driving force, and the pollutants can only be removed together with the anodic oxidation film by chemical film stripping. In addition, for more complex mixed pollutants, especially multiphase mixtures, such as mixtures of fine-grained graphite or metal powder and heavy oil grease, it is more difficult to effectively remove them by traditional cleaning methods. For metal assemblies with such film layers, since the reworkability is poor, once contaminated, it means the loss of usability of the parts, and in severe cases, they need to be scrapped.

[0005] The patent document with the publication number CN112620230A discloses a cleaning method for parts, including the following steps: grinding the surface of the workpiece; placing the workpiece in at least one solvent among diesel, kerosene, and alcohol for ultrasonic cleaning; spraying the surface of the workpiece with water and drying; placing the workpiece in acetone for ultrasonic cleaning; placing it in isopropyl alcohol for ultrasonic cleaning; and cleaning with water to obtain the cleaned part. This invention combines different types of solvent cleaning and ultrasonic cleaning, and can clean workpieces with precise and complex structures, but it is necessary to first grind the surface of the workpiece and is not applicable to cleaning workpieces that need to maintain the surface integrity.

[0006] The patent document with the publication number CN103071640A discloses a cleaning method for an electro-discharge machined micro-textured metal surface, including immersing the metal in kerosene and cleaning it by ultrasonic oscillation, but the use of hydrochloric acid aqueous solution will affect the performance of the aluminum alloy oxide film. Summary of the Invention

[0007] To solve the above technical problems, the present invention provides a method for removing oxide film immersion-type contaminants.

[0008] The present invention is achieved through the following technical solutions.

[0009] A method for removing oxide film immersion-type contaminants provided by the present invention includes one of Method A and Method B. Method A includes the following steps:

[0010] S1: Mix solution a and cleaning agent a to obtain mixed solvent a;

[0011] S2: Immerse the workpiece to be cleaned below the liquid level of mixed solvent a and then let it stand;

[0012] S3: After taking out the workpiece, clean it with flowing water and then let it stand to dry at room temperature.

[0013] Method B includes the following steps:

[0014] S1: Mix solvent a and cleaning agent b to obtain mixed solvent b, heat it, and then add solution b to mixed solvent b and stir to obtain mixed solvent c;

[0015] S2: Immerse the workpiece to be cleaned below the liquid level of mixed solvent c and then perform ultrasonic cleaning;

[0016] S3: After taking out the workpiece, clean it with flowing water and then let it stand to dry at room temperature.

[0017] Preferably, the solution a is absolute ethanol, the cleaning agent a is aviation cleaning gasoline, the solvent a is water, the cleaning agent b includes one or more of aviation cleaning gasoline and aviation kerosene, and the solution b is a non-ionic surfactant.

[0018] Preferably, in step S1 of method A, the solution a and the cleaning agent a are mixed at a volume ratio of 3 - 4:6 to obtain a mixed solvent a.

[0019] Preferably, in step S1 of method B, the solvent a and the cleaning agent b are mixed at a volume ratio of 2 - 3:1 to obtain a mixed solvent b.

[0020] Preferably, in step S1 of method B, the heating temperature is 50 - 60 °C.

[0021] Preferably, in step S1 of method B, a solution b that is 2 - 2.5 times the CMC value is added to the mixed solvent b and stirred to obtain a mixed solvent c.

[0022] Preferably, in step S3 of method B, the ultrasonic cleaning frequency ≥ 40 kHz, and the cleaning time is 5 - 25 min.

[0023] Preferably, in step S3 of method B, the ultrasonic cleaning is performed at room temperature, and the number of cleaning times ≥ 2 times.

[0024] Preferably, the solution b is a non-ionic surfactant with an HLB value of 13 - 20.

[0025] The beneficial effects of the present invention are as follows:

[0026] The present invention provides cleaning methods for workpieces contaminated by heavy oil pollution type pollutants, complex oil pollution and solid powder pollution respectively, and the cleaning rate reaches at least 90%.

[0027] For the case where pollutants of the heavy oil pollution type penetrate into the oxide film, such as the tapping oil used when drilling and tapping oxidized parts, the average molecular weight of such pollutants is large, the solubility is poor, the surface tension is large, the fluidity is poor, and they are relatively stubborn after pollution and difficult to remove. The present invention uses a low-tension and medium-polarity mixed solvent, adopts a completely immersed method, and uses the concentration gradient of the pollutant concentration as the driving force to slowly dissolve it from the pores of the film layer to achieve the purpose of cleaning.

[0028] For the case where a mixture of complex oil stains and solid powders penetrates into the oxide film, such as when the surface of a part after oxidation is contaminated with graphite powder or metal powder and then contaminated by complex oil stains, the adhesion between such contaminants and the surface is relatively complex and difficult to remove. The present invention uses a special emulsifying liquid formulated with a specific HLB value and, by increasing ultrasonic cleaning, simultaneously removes different oil stains and solid powders through the solubility of the emulsifying liquid in the mixed oil stains, the solubilization of the surfactant, and the emulsifying and peeling effects of ultrasonic waves, achieving the purpose of cleaning. Detailed implementation mode

[0029] The technical solution of the present invention is further described below, but the scope of protection claimed is not limited thereto.

[0030] Example 1:

[0031] A method for removing contaminants of the oxide film immersion type includes the following steps:

[0032] S1: Mix 5L of anhydrous ethanol and 10L of 180# aviation cleaning gasoline to obtain a mixed solvent a;

[0033] S2: Immerse the workpiece to be cleaned below the liquid level of the mixed solvent a and then let it stand for 4h;

[0034] S3: After taking out the workpiece, clean it with flowing clear water and then let it stand to dry at room temperature.

[0035] This example is for cleaning contaminants of the heavy oil stain type that penetrate into the oxide film.

[0036] Example 2:

[0037] A method for removing contaminants of the oxide film immersion type includes the following steps:

[0038] S1: Mix 10L of water and 5L of 180# aviation cleaning gasoline to obtain a mixed solvent b. After heating to 50°C, slowly add 3g (10 * 603 * 0.23 * 0.001 * 2) of OP-10 surfactant (CAS is 9002-695-5, non-ionic type, molecular weight 603, HLB value 13 - 14, CMC value about 0.23 mM) to the mixed solvent b and immediately stir well to form a slightly foamy emulsion-like state to obtain a mixed solvent c;

[0039] S2: Immerse the workpiece to be cleaned below the liquid level of the mixed solvent c and then perform ultrasonic cleaning. The ultrasonic cleaning frequency is 40 kHz, the cleaning time is 10 min, the ultrasonic cleaning is carried out at room temperature, and the cleaning times are 2 times;

[0040] S3: After taking out the workpiece, clean it with flowing clear water and then let it stand to dry at room temperature.

[0041] This embodiment is for cleaning the complex mixture of oil stains and solid powders infiltrated into the oxide film.

[0042] Example 3:

[0043] A method for removing oxide film immersion-type pollutants, comprising the following steps:

[0044] S1: Mix 10 L of water and 5 L of aviation kerosene to obtain mixed solvent b. After heating to 60 °C, slowly add 3 g (10 * 603 * 0.23 * 0.001 * 2) of OP-10 surfactant (CAS: 9002-695-5, non-ionic, molecular weight 603, HLB value 13 - 14, CMC value about 0.23 mM) to mixed solvent b and immediately stir well to form a slightly foamy emulsion-like mixture to obtain mixed solvent c;

[0045] S2: Immerse the workpiece to be cleaned below the liquid level of mixed solvent c and then perform ultrasonic cleaning. The ultrasonic cleaning frequency is 40 kHz, the cleaning time is 10 min, the ultrasonic cleaning is carried out at room temperature, and the number of cleaning times is 2 times;

[0046] S3: After taking out the workpiece, clean it with flowing clean water and then leave it to dry at room temperature.

[0047] This embodiment is for cleaning the complex mixture of oil stains and solid powders infiltrated into the oxide film.

[0048] Comparative Example 1

[0049] Immerse the workpiece to be cleaned below the water level and then perform ultrasonic cleaning. The ultrasonic cleaning frequency is 40 kHz, the cleaning time is 10 min, the ultrasonic cleaning is carried out at room temperature, and the number of cleaning times is 2 times.

[0050] Comparative Example 2

[0051] Immerse the workpiece to be cleaned below the liquid level of acetone and then perform ultrasonic cleaning. The ultrasonic cleaning frequency is 40 kHz, the cleaning time is 10 min, the ultrasonic cleaning is carried out at room temperature, and the number of cleaning times is 2 times.

[0052] Comparative Example 3

[0053] Wipe the workpiece with a towel and anhydrous ethanol.

[0054] Use the methods of Example 1 and Comparative Examples 1 - 3 to clean 20 workpieces with a surface area of 0.5 M 2 of aluminum alloy sulfuric acid anodized surface Al / Et.A(S).S contaminated by heavy oil infiltrated into the oxide film.

[0055] The cleaning rate using the method of Example 1 is 90%, the cleaning rate using the method of Comparative Example 1 is 60%, the cleaning rate using the method of Comparative Example 2 is 70%, and the cleaning rate using the method of Comparative Example 3 is 1%.

[0056] Using the methods of Examples 2-3 and Comparative Examples 1-3, 20 workpieces with a surface area of 0.5 M 2 of the micro-arc oxidation surface of aluminum alloy, where the Al / Et.MAO is contaminated by graphite powder and oil stain infiltrating into the oxide film, are cleaned respectively.

[0057] The cleaning rate using the method of Example 1 reaches 90% on average, the cleaning rate using the method of Example 2 is 95%, the cleaning rate using the method of Example 3 is 100%, the cleaning rate using the method of Comparative Example 1 is 40%, the cleaning rate using the method of Comparative Example 2 is 60%, and the cleaning rate using the method of Comparative Example 3 is 5%.

[0058] The measurement method of the above cleaning effect refers to the rubbing method in 4.2.1 of "Test Methods for Scale Removal Rate and Cleaning Rate in Chemical Cleaning of Industrial Equipment" (GB / T 25148-2010), which is for the determination of cleaning rate in 4.2.

Claims

1. A method for removing immersion-type pollutants from an oxide film, characterized in that: Include one of Method A and Method B. Method A includes the following steps: S1: Mix solution a and cleaning agent a to obtain mixed solvent a; S2: Immerse the workpiece to be cleaned below the liquid level of mixed solvent a and then let it stand; S3: Take out the workpiece, clean it with flowing clear water, and then let it stand to dry at room temperature; Method B includes the following steps: S1: Mix solvent a and cleaning agent b to obtain mixed solvent b. After heating, add solution b to mixed solvent b and stir to obtain mixed solvent c; S2: Immerse the workpiece to be cleaned below the liquid level of mixed solvent c and then perform ultrasonic cleaning; S3: Take out the workpiece, clean it with flowing clear water, and then let it stand to dry at room temperature.

2. The method for removing immersion-type contaminants on an oxide film according to claim 1, wherein: Solution a is absolute ethanol, cleaning agent a is aviation cleaning gasoline, solvent a is water, cleaning agent b includes one or more of aviation cleaning gasoline and aviation kerosene, and solution b is a non-ionic surfactant.

3. The method for removing immersion-type pollutants from an oxide film according to claim 1, characterized in that: In step S1 of Method A, solution a and cleaning agent a are mixed at a volume ratio of 3 - 4:6 to obtain mixed solvent a.

4. A method for removing immersion-type pollutants on an oxide film according to claim 1, characterized in that: In step S1 of Method B, solvent a and cleaning agent b are mixed at a volume ratio of 2 - 3:1 to obtain mixed solvent b.

5. A method for removing immersion-type contaminants on an oxide film according to claim 1, characterized in that: In step S1 of Method B, the heating temperature is 50 - 60°C.

6. The method for removing immersion-type pollutants from an oxide film according to claim 1, characterized in that: In step S1 of Method B, add 2 - 2.5 times the CMC value of solution b to mixed solvent b and stir to obtain mixed solvent c.

7. The method for removing immersion-type pollutants from an oxide film according to claim 1, characterized in that: In step S3 of Method B, the ultrasonic cleaning frequency ≥ 40 kHz, and the cleaning time is 5 - 25 min.

8. The method for removing immersion-type pollutants from an oxide film according to claim 1, characterized in that: In step S3 of Method B, ultrasonic cleaning is performed at room temperature, and the number of cleaning times ≥ 2 times.

9. The method for removing immersion-type contaminants from an oxide film according to claim 2, characterized in that: Solution b is a non-ionic surfactant with an HLB value of 13 - 20.