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.
Yes, yellow chromated and yellow passivated are the same -- meaning an electroplated finish (usually zinc plating because it's the least expensive) followed by a yellow chromate conversion coating. 1  2. Black finish doesn't imply anything except the color. 2  3. Passivate is a tricky one because it means different things for different substrates.