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.
Aluminium and aluminium alloys are treated by a corrosion resistant conversion coating that is called chromate coating or chromating.General method is to clean the aluminium surface and then apply an acidic chromium composition on that clean surface.luminium and aluminium alloys are treated by a corrosion resistant conversion coating that is called chromate coating or chromating.