Philadelphia, Pa., for her question:
DOES CHROMIUM HAVE MANY USES?
A thin coat of chromium metal is used to protect bumpers and automobile parts from rusty corrosion. And, just for fun, it glints like shiny silver in the sun. Other forms of chromium work behind the scenes to improve other metals, to create paints and polishes, leathers and photographs and furnace linings. And just for fun it takes time from its choresto add the color to a couple of precious gems.
Chromium in its pure form is not found in the earth’s crust, possibly because Mother Nature regards it as too useful to be left lying around. However, it is there in large quantities, though disguised with iron and oxygen in a mineral ore called chromite. When separated, the silvery metal rates as a chemical element made from atoms that are all alike.
This hard, handsome metal resists rusty corrosion, which is why we see it on auto parts and metal appliances. A thin coating is enough to do a protective job. This is fortunate because the glamorous metal is very difficult to shape. A thin coat is added, atom by atom, by the process of electroplating.
Chromium is not so temperamental about working with other metals. When alloyed, or mixed with steel, it creates tough armor plating for ships. Chromium steel is tough enough to make ball bearings and other heavy duty machine parts. When these alloys contain 10% to 18% of chromium, they are tough, rustproof stainless steels.
Most of its useful chores are done behind the scenes when chromium forms chemical compounds with other substances. Certain chromium compounds are used to fix, or make permanent, various dyes for the textile industry. A chromium and potassium compound is used to tan leather. Others form yellowish pigments used to make paints.
An alloy of chromium and nickel forms a tough, heat resistant metal used in kitchen stoves and various heaters. Chromite, a form of natural chromium ore, is used to line furious furnaces.
The name chromium was coined from an older word meaning color. This seemed logical because its compounds add colors to the artists’ paint box. In nature, the fascinating element adds the green to precious emeralds and the red to the precious rubies.