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.
1 This method of oxidizing aluminum is not the same as anodizing aluminum. 2  Anodizing is a process of artificial oxidation using an acid and electricity to create a strong surface on the metal. 3  Dye can be added to the acid to change the surface color of anodized aluminum.luminum has a high strength-to-weight ratio, and its patina is the same color as the metal. Therefore, many industries use aluminum, in place of steel or plastic, for strong, lightweight parts that resist corrosion.