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.
passivated. 1  transitive verb. 2  1 : to make inactive or less reactive passivate the surface of steel by chemical treatment. 3  2 : to protect (something, such as a solid-state device) against contamination by coating or surface treatment.