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Aluminum alloy surface acid remove oil method

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Acid degreasing treatment is also a widely used degreasing method. The main feature of the acid degreaser is that it has less erosion on the surface of the aluminum alloy and has a faster degreasing speed. The most economical method of preparing such a degreaser is to add a small amount of ammonium bifluoride and OP emulsifier to the sulfuric acid solution, or directly to the market to purchase an acidic degreaser.
 
 
 
Acid degreasers generally consist of inorganic or organic acids, surfactants, corrosion inhibitors and penetrants. Acid degreasing is also a common degreasing method for metal surfaces. The characteristic of acid degreasing is that it does not need to be heated, and it can have a good degreasing effect under normal temperature conditions. In recent years, the development of some acid degreasing additives has made acid degreasing widely used, and acid degreasing also has a derusting function. When acid degreasing is used, the acid concentration should not be too high to avoid corrosion of the workpiece and corrosion of the equipment. Acids commonly used in acid degreasers are sulfuric acid, phosphoric acid, nitric acid, citric acid and the like. Surface activity is commonly used as OP-10, pingping, sulfonic acid and the like. For the aluminum alloy, a halogen acid such as hydrochloric acid cannot be used. The addition of phosphoric acid to the acidic degreaser facilitates the cleaning process. Corrosion inhibitors should also be added to the degreaser. Commonly used slow etching is urotropine, thiourea and the like. Fluoride is the most commonly used penetrant in acidic degreaser. The addition of fluoride can significantly enhance its degreasing effect, reduce acid concentration and improve degreasing efficiency. In the acid degreasing formula of the aluminum alloy workpiece, the amount of fluoride added should not be too much, otherwise the titanium hanger will be corroded, and too much fluoride will reduce the gloss of the aluminum alloy surface after degreasing. In the acidic degreasing formula of aluminum alloy, it is generally added in the form of ammonium hydrogen fluoride, and the amount of addition is preferably about 1 g/L. At the same time, an appropriate amount of boric acid and nitrate should be added to prevent etching of titanium and to slow the corrosion of the aluminum alloy.
 
 
 
Acid degreasing is generally carried out under normal temperature conditions. If heated to about 40 °C, the degreasing effect can be obviously improved. When the oil is removed at room temperature, the working cylinder can be made of hard PVC. When heating and degreasing, PP should be used. The Teflon heater is used for the heating of the acidic degreasing solution.
 
 
 
The amount of ammonium hydrogen fluoride in the acid degreaser should not be too much, otherwise it will corrode the titanium hanger and affect the surface properties of the aluminum. Too high a concentration of aluminum ions can affect the low temperature degreasing effect, but can be improved by increasing the concentration of fluoride or nitric acid.
 
 
 
The aluminum alloy acid degreaser can be prepared by using waste acid such as sulfuric acid anodizing or chemical polishing to achieve waste utilization and reduce cost. If the reuse of waste acid is not considered, the acid degreaser can also be prepared by using sulfonic acid and a small amount of ammonium hydrogen fluoride, so that the acidity of the degreasing solution is very low, and the corrosion of the workpiece or equipment will be low. 

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