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 most notable characteristic of metals being passivated is that they will sustain zero corrosion. Another characteristic is that passivated metals do not act accordingly to the metal activity sequence (Ionization Tendency) but will act rather like they belong in the Noble region of the metal activity sequence.