Alloys of cobalt

Alloys of cobalt : - Cobalt is a hard, lustrous, grey metal, a chemical element with symbol Co and atomic number 27. Although cobalt-based colors and pigments have been used since ancient times, and miners have long used the name kobold ore for some minerals, cobalt was only discovered in 1735 by Georg Brandt. It is found in various metallic-lustred ores for example cobaltite (CoAsS), but it is produced as a by-product of copper and nickel mining. The copper belt in the Democratic Republic of the Congo and Zambia yields most of the worldwide mined cobalt. Cobalt is used in the preparation of magnetic, wear-resistant, and high-strength alloys. Cobalt blue (cobalt(II) aluminate, CoAl2O4) gives a distinctive deep blue color to glass, ceramics, inks, paints, and varnishes.

Precautions : - Although cobalt is an essential element for life in minute amounts, at higher levels of exposure it shows mutagenic and carcinogenic effects similar to nickel (see Cobalt Poisoning). The addition of cobalt compounds to stabilize the beer foam in Canada in 1966 led to Cardiomyopathy, which came to be known as beer drinker's cardiomyopathy. Powdered cobalt in metal form is a fire hazard. After nickel and chromium, cobalt is a major cause of contact dermatitis