Why are aluminum parts cleaned with nitric acid and hydrofluoric acid?

The aluminum parts processing industry has been to clean oil removal mainly by acid cleaning, using acid reaction to remove the surface of aluminum oil, but also to remove the raw edge of the product, so that the product surface oxidized to white. However, the high precision requirements of aluminum products should not use acid aluminum products cleaning agent. In addition to the oil to be completely removed at the same time can not have any impact on the surface of the product, do not change the color, size.


Nitric acid:
1. As a necessary raw material for nitrates and nitrates, nitric acid is used to prepare a series of nitrates nitrogen fertilizer, such as ammonium nitrate and potassium nitrate.
2. Also used in the military.
3. Since nitric acid is both oxidizing and acidic, nitric acid is also used to refine metals: the impure metals are oxidized into nitrates, and the impurities are removed before reduction. Nitric acid can passivate iron without further corrosion. Also available for making nitrogen fertilizer, wang shui, nitrates, nitroglycerine, nitrocellulose, nitro-benzene, picric acid.
Hydrofluoric acid:
Hydrofluoric acid plays an important role in the purification of aluminum and uranium due to its ability to dissolve oxides. Hydrofluoric acid is also used to etch glass, which can carve patterns, mark marks and text. The semiconductor industry USES it to remove oxides from silicon, it can be used in refineries as a catalyst for alkylation of isobutane and n-butene, and hydrofluoric acid is used to remove oxygen-containing impurities from stainless steel surfaces. Hydrofluoric acid is also used in the synthesis of a variety of fluoroorganic compounds, such as Teflon(polytetrafluoroethylene) and refrigerants such as freon.