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.
In its pure form, the element is very hard to machine and very brittle. The main application of iridium is as a hardening agent of platinum. High temperature equipment such as crucibles is made from platinum-iridium alloys.Alloys made of osmium and iridium are used to produce elements of fountain pens.Given that this element is corrosive-resistant, an alloy of 10 percent iridium and 90 percent platinum was used to create the standard meter bar.n its pure form, the element is very hard to machine and very brittle. The main application of iridium is as a hardening agent of platinum. High temperature equipment such as crucibles is made from platinum-iridium alloys.