Silicon Alloys

(Si) Atomic Number 14

Silicon is a metalloid; it has characteristics of both metals (shiny metallic appearance, strong) and non-metals (brittle, not a good conductor of electricity).

After being isolated as an element it was originally called Silicium, the "ium" suffix denoting a metal in the same fashion as Aluminium. In many countries the name was soon changed to Silicon to reflect its similarity to other metalloid elements such as Carbon and Boron.

A commonly occurring element in the universe, it is the second most common element found within the Earth crust after Oxygen. It is widely available in various forms such as quartz, sand, rock crystals, amethyst, agate, flint, jasper and opal.

It is an unusual element in that it has a lower density when in solid state than in liquid state, so like ice floating on water it expands when it freezes rather than contracts and the frozen solid floats on the liquid.


About 80% of the world's production of elemental silicon is used to produce Ferro silicon, an alloy of Iron and Silicon which is primarily used in the steel industry. Ferro Silicon can contain anything from 15-90% by weight of Silicon and is primarily used to deoxidise steel and ferrous alloys. In the manufacture of cast iron it is used as an inoculant to improve the casting properties.

Silicon metal is widely used in the Aluminium alloying industry where it also gives Aluminium alloy good casting properties. These are used widely in engineering structures and components where light weight and corrosion resistance is required.

Use of highly purified silicon in Semiconductors which accounts for only 10% of utilisation has arguably accounted for Silicon's largest impact on modern life because most modern computers depend upon Silicon in integrated circuits. As a result it has given its name to many places that specialise in high technology devices such as Silicon Valley, California, and then subsequently Silicon Forest, Oregon, Silicon Hills, Texas, Silicon Saxony, Germany, Silicon Valley, India, Silicon Fen, Gorge and Roundabout in England and Silicon Glen in Scotland.

Apart from the metals and electronics industry Silicon has a large number of uses in a wide range of applications. In some of its various naturally occurring forms such as clays, silica sand, and building stone it is utilised as building material. It is a key component in Portland cement which can also be combined with silica sand and gravel to make concrete.

It can be found in ceramics, glass, and more recently it has been increasingly employed in the form of Poly Silicon in the production of solar cells to utilise solar power for energy generation. It is predicted that increased demand for solar technology will create increasing demand for high grades of Silicon Metal.