This painless condition occurs when the little bumps on your tongue grow long and trap bacteria that live in your mouth -- making the tongue look black and hairy. Causes can include antibiotic use, poor oral hygiene, smoking, drinking a lot of tea or coffee, and not producing enough saliva.
Hello, Jie. The word passivate is a bit troublesome because aluminum cannot be passivated in the same sense as stainless steel; but it can be passivated in the same sense as zinc plating, i.e., with a chromate conversion coating.
The corrosion resistance of stainless steel depends on the formation of a âpassive surface ï¬lmâ composed of nickel and chromium oxides (Cr 2 0 3 & Ni0). Passivation involves removing free Fe or âtramp Feâ from the stainless steel surface. This is the purpose of Pascal. The nitric acid in Pascal enriches the stainless steel with Cr & Ni. The oxides (Cr 2 0 3 & Ni0) then form and a passive surface now is in place.Steps:1.