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 passivation process will remove the free iron and other contaminates from the stainless and promote the formation of the beneficial oxide film. I suspect that the pool hand rail and diving board manufactures don't use a passivation step on their stainless steel. It makes some sense given that prior to the advent of SWG (salt pools), there was little need. With the SWG, and thus the salt (electrolyte), it would make more sense to have this done.