As a metal powder, silicon is irreplaceable in pyrotechnic ignition mixtures used in mining and in airbags. Silicon nitride is a high-performance ceramic that is suitable for extreme thermal and mechanical loads. Examples of applications include cutting and machining tools, ball bearings and components in combustion engines and power units. It is also used in melting, soldering and welding processes. The aluminum and steel industries process silicon in alloys. As a semiconductor whose electrical properties can be specifically controlled, it is an essential component in transistors. The electronics industry also requires the raw material in the form of high-purity polysilicon for the production of solar cells. Silicon dioxide and silicates are used in the production of glass, glazes, enamels, cement and porcelain.