Page 36 - Curriculum Visions Dynamic Book

Chromium
Chromium was named after “chroma”,
the Greek word for colour, because of
the many coloured compounds that it makes. Among these are the rich red of rubies and the brilliant green of emeralds.
The main ore of chromium is chromite, found in combination with some iron ores.
Chromium ore is refined into shiny, silvery- white chromium metal. However, because chromium metal is brittle and hard, it has
no uses on its own.
Chrome alloys
Chromium is used as an alloy with steel. Chrome steels are strong and hard and are often used for making tools. Chromium is always a component of stainless steel.
Alloys of nickel and chromium are used for high temperature wire elements in electric fires and other appliances.
 A piece of highly reflective chromium metal.
Chromium plating
Because chromium resists corrosion, is hard-wearing and has an attractive silvery colour that does not tarnish,
it is widely used to plate iron and brass.
All items to be chromium plated are dipped in a bath containing chromium compounds in solution. In some cases, the articles to be plated are simply dipped in chromium metal. But a thin, even finish is created by using the process of electrolysis. In this case
the articles to be plated are attached to the negative end of an electrical circuit, and the surface is then plated.
Corrosion inhibitors
Because chromium compounds resist corrosion, they can be used as corrosion inhibitors in water cooling systems, such as that of a motor vehicle.
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