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The properties of silicon may be used to modify alloys with metals other than iron. "Metallurgical grade" silicon is silicon of 95–99% purity. About 55% of the world consumption of metallurgical purity silicon goes for production of aluminium-silicon alloys ( silumin alloys) for aluminium part casts , mainly for use in the automotive industry .
In the modern world, iron alloys, such as steel, stainless steel, cast iron and special steels, are by far the most common industrial metals, due to their mechanical properties and low cost. The iron and steel industry is thus very important economically, and iron is the cheapest metal, with a price of a few dollars per kilogram or pound.
The elements commonly classified as metalloids are boron, silicon, germanium, arsenic, antimony and tellurium. [n 4] The status of polonium and astatine is not settled. Most authors recognise one or the other, or both, as metalloids; Herman, Hoffmann and Ashcroft, on the basis of relativistic modelling, predict astatine will be a monatomic metal.
It melts at 1414 °C. Silicon is a semiconductor with an electrical conductivity of 10 −4 S•cm −1 [287] and a band gap of about 1.11 eV. [281] When it melts, silicon becomes a reasonable metal [288] with an electrical conductivity of 1.0–1.3 × 10 4 S•cm −1, similar to that of liquid mercury. [289]
Iron is always the main element in steel, but many other elements may be present or added. Stainless steels, which are resistant to corrosion and oxidation, typically are 11% chromium. Iron is the base metal of steel. Depending on the temperature, it can take two crystalline forms (allotropic forms): body-centred cubic and face-centred cubic.
As a result, the properties of ductile cast iron are that of a spongy steel without the stress concentration effects that flakes of graphite would produce. The carbon percentage present is 3-4% and percentage of silicon is 1.8-2.8%.Tiny amounts of 0.02 to 0.1% magnesium , and only 0.02 to 0.04% cerium added to these alloys slow the growth of ...
The base metal iron of the iron-carbon alloy known as steel, undergoes a change in the arrangement of the atoms of its crystal matrix at a certain temperature (usually between 820 °C (1,500 °F) and 870 °C (1,600 °F), depending on carbon content). This allows the smaller carbon atoms to enter the interstices of the iron crystal.
Ferrosilicon is used as a source of silicon to reduce metals from their oxides and to deoxidize steel and other ferrous alloys. This prevents the loss of carbon from the molten steel (so called blocking the heat); ferromanganese, spiegeleisen, calcium silicides, and many other materials are used for the same purpose. [5]