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 (or aluminum; see different endings) is a chemical element in the boron group with symbol Al and atomic number 13.It is a silvery-white, soft, nonmagnetic, ductile metal. Aluminium is the third most abundant element (after oxygen and silicon) in the Earth 's crust, and the most abundant metal there.It makes up about 8% by mass of the crust, though it is less common in the mantle below.t is a silvery-white, soft, nonmagnetic, ductile metal. Aluminium is the third most abundant element (after oxygen and silicon) in the Earth 's crust, and the most abundant metal there. It makes up about 8% by mass of the crust, though it is less common in the mantle below.