Editing Refractory (section)

{{Short description|Materials resistant to decomposition under high temperatures}}
{{About|heat resistance}}

[[File:Torpedo car refractory bricks.JPG|thumb|Refractory bricks in a [[Ladle transfer car|torpedo car]] used for hauling molten iron]]

In [[materials science]], a '''refractory''' (or '''refractory material''') is a [[material]] that is resistant to [[Thermal decomposition|decomposition by heat]] or chemical attack and that retains its strength and rigidity at high [[temperature]]s.<ref>{{cite book |author = Ailsa Allaby and Michael Allaby |title= Concise Dictionary of Earth Sciences |year = 1996 |publisher= Oxford Paperbacks Oxford University Press}}</ref> They are [[Inorganic compound|inorganic]], [[Nonmetal|non-metallic]] compounds that may be [[Porosity|porous]] or non-porous, and their [[crystallinity]] varies widely: they may be [[Crystal|crystalline]], [[polycrystalline]], [[Amorphous solid|amorphous]], or [[Composite material|composite]]. They are typically composed of [[oxide]]s, [[carbide]]s or [[nitride]]s of the following elements: [[silicon]], [[aluminium]], [[magnesium]], [[calcium]], [[boron]], [[chromium]] and [[zirconium]].<ref name="IspatGuru">{{Cite web|url=https://www.ispatguru.com/refractories-and-classification-of-refractories/|title=Refractories and Classification of Refractories |work=IspatGuru|access-date=2020-03-06}}</ref> Many refractories are [[ceramic]]s, but some such as [[graphite]] are not, and some ceramics such as [[clay pottery]] are not considered refractory. Refractories are distinguished from the ''[[refractory metals]]'', which are elemental [[metal]]s and their [[alloy]]s that have high melting temperatures.

Refractories are defined by [[ASTM International|ASTM]] C71 as "non-metallic materials having those chemical and physical properties that make them applicable for structures, or as components of systems, that are exposed to environments above {{convert|1000|F|K C}}".<ref>ASTM Volume 15.01 ''Refractories; Activated Carbon, Advanced Ceramics''</ref> Refractory materials are used in [[Metallurgical furnace|furnace]]s, [[kiln]]s, [[incinerator]]s, and [[Nuclear reactor technology|reactors]]. Refractories are also used to make [[crucible]]s and [[Molding (process)|molds]] for casting glass and metals. The [[Ferrous metallurgy|iron and steel industry]] and metal casting sectors use approximately 70% of all refractories produced.<ref name="SAIMM">
{{cite journal
 | title= How cool are refractory materials?
 | url = http://www.saimm.co.za/download/PresidentialAddress2008.pdf
 | year = 2008
 | journal = The Journal of the Southern African Institute of Mining and Metallurgy
 | volume = 106
 | issue = September
 | pages = 1–16
 | access-date = 22 April 2016 
 }}
</ref>