Background

Nickel discovered in 1751 in kupfernickel (niccolite) by Crostedt, is obtained commercially from pentlandite and pyrrhotite.

Nickel is a silvery-white metal and takes on a high polish. It is hard, malleable, ductile and to an extent ferromagnetic (up to 360°C). It has a fair electrical conductivity (25% that of copper) and heat conductivity. It belongs to the iron-cobalt group of metals. Nickel is highly resistant to atmospheric corrosion and resists most acids, but is attacked by oxidising acids such as nitric acid.

Natural nickel is a mixture of five stable isotopes, while nine other unstable isotopes are known.

Nickel carbonyl is considered very toxic and exposure should be very limited. The fumes and dust of nickel sulphide are recognised as having carcinogenic potential.
Applications

Nickel metal has the following applications:

· Its principal use is as an alloying element in stainless steels, alloys steels, non-ferrous metals and other corrosion resistant alloys, examples of which are: Invar®, Monel®, Inconel®, Nichrome®, Permalloy® and the Hastelloys®.

· Nickel coatings can be deposited electrolytically by electroplating, chemically by electroless or autocatalytic deposition.

· Tubing for desalination plants.

· Coinage.

· Additives in amour plate and burglarproof vaults metals.

· In glass to produce a green colour.

· As a catalyst for hydrogenating vegetable oils.

· Ceramic manufacturing.

· Alnico magnets.

· Storage batteries, e.g. nickel-cadmium and nickel-metal hydride based batteries. Such batteries are rechargeable and used for mobile phones, personal stereo equipment and the like.

· High purity nickels are used in electronic and aerospace applications, chemical and food processing equipment, for anodes and cathodes, caustics evaporators and heat shields.

· Aircraft turbines components.

· Beryllium nickel is used for springs, switches, bellows, diaphragms and small valves

· Thermometer bulbs and resistance thermometers.

· Glass to metal and ceramic to metal seals.

· Marine, petroleum and chemical processing equipment. (e.g. Monels).

· Incineration systems.

· Controlled expansion nickel superalloys.

· Paramagnetic alloys and shape memory alloys (e.g. Nitinol) are used in fire-sprinkler actuators, tap water anti-scalding devices, green house window hinges, flow regulators, spacecraft solar-panel releases, numerous toys and novelties and under wire brassieres.