View source for Refractory

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A '''refractory''' is a material which is resistant to high temperatures. It is used in the construction of furnaces, crucibles, [[rocket]] nozzles and other applications where a material is required to remain solid at high temperatures and especially when it is required to have good mechanical strength at high temperature.<br />
Many carbides make good refractory materials, as do some metal oxides. A few metals, notably [[tungsten]] and [[niobium]], also have useful high-temperature properties (although metals are not normally regarded as refractories).

The Earth's moon, Luna, was created when a Mars sized body collided with Earth soon after the Sun formed.  The refractory elements soon solidified from the torus of gas, while the elements and compounds with low temperatures of vaporization, had more time to expand and escape from the Earth's orbit.  Thus Luna is enriched with refractory elements.  Mars has a mixture of compounds more like Earth, in that respect.

==Examples==
* [[Silicon carbide]]
* [[Alumina]]
* [[Graphite]]
* [[Kaolin]]
* [[Silica]]

[[Category:Materials]]