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.
Optimum rare earth levels in a nodularizer are a function of the purity of the raw. materials used and of casting m ethodology. Calcium moderates the reaction between the Magnesium and the base iron, reducing its. violence. However, excessive calcium in the alloy may produce slag. The presence of. aluminum can under certain conditions promote pinhole formations in Ductile Iron and must be. controlled .