Anticorrosion of magnesium alloy sheet

Degreasing treatment

In order to remove grease, residual process lubricating oil and other dirt from the surface of magnesium alloy plate, degreasing and pickling must be carried out before oxidation and coloring, which is not only an essential preparation process, but also a key process of surface treatment. to ensure that the surface has good wettability. First of all, it is appropriate to have some understanding of the surface condition of the plate, and then determine each step of the degreasing process.

1. The plates that need to be re-oxidized and colored after the oil seal are first degreased with steam or Scald at 95 ℃ ~ 100C, then wiped with pure gasoline or white oil, and finally put into the degreasing tank.

two。 There are a lot of process lubricating oil left on the newly rolled plate, which can be degreased with soda solution containing (0.5%-1.0%) soda, the solution temperature is 90 ℃ ~ 100 ℃, and the cleaning is about 30min.

3. The local oil stain on the surface of the plate should be cleaned or wiped with organic solvents.

If washing oil or other organic matter is used as process lubricant during rolling, the special degreasing process can be avoided, and the local oil stains on the finished product after pickling can be removed with hand-held grinding wheel or scraper.

Bright etching

The bright etching of magnesium and magnesium alloys can be referred to as light washing, and it is also pickling in nature, but its reaction is mild and slow, which is a key process before oxidation and coloring. The aim is to thoroughly purify the wheat flour of the plate, remove the "hanging ash" remaining on the surface during pickling, and basically do not dissolve Mg itself, but show the true color of magnesium and magnesium alloy-bright and clean.

There are many kinds of light cleaning solution, but chromic anhydride (Cr2O3) solution is often used, and sometimes a small amount of activator is added. The most important factor affecting the quality of light washing is the content of NaNO3 or KNO3, Cr and SO2-.