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.
Aluminum is one of the best metals for heat conductivity next to copper, and is ideal for applications where heat exchangers are required. Because it is so reactive, aluminum is useful as an additive or catalyst in chemical fusions, which can include use in ammonium nitrate explosives to intensify the explosive power.