Any material that withstands the high heat needed for melting glass, the two most common being clay and ceramic fiber substances. Special clays fire up to form bricks that do not deform in the heat. If previously fired clay (grog) and organic material is added to the mix, insulating firebrick is created by the empty spaces in the fired clay. Ceramic fiber is a result of space research and insulates. Two other refractories, known to gardeners, and sometimes used as insulation are vermiculite, which is expanded mica from volcanic regions and perlite, which is made in some way.
The property of being able to exist in solid form under conditions of very high temperature. Refractory elements are characterized by a high temperature of vaporization; they are the first to condense into solid form when a gas cools, as in the solar nebula.
Material that is design to withstand heat and high temperatures. The Refractory Material that Forno Bravo uses for its Pizza Ovens and Refractory Fireplaces is a high-tech composite of tempered alumina and woven ceramic silica. For more, read our Refractory Primer.
A metal or ceramic having a high melting temperature, usually over 1700 C. Example refractory metals are tungsten, molybdenum, rhenium, and zirconium, while example refractory ceramics are alumina, zirconia, yttria, and chromia.
Heat-resistant material, usually non-metallic, used for furnace linings etc. The quality of resisting heat. Material usually made of ceramics, which is resistant to high temperatures, molten metal, and slag attack.
Resistant to melting or fusion; a ware or material that does not fuse under 2500 degrees Fahrenheit; a substance that raises the melting point of another material. Refractory materials are the basis of high temperature ceramics.
Refractory is the quality of a material to retain its strength at high temperatures. Refractory materials are used to make crucibles and linings for furnaces, kilns and incinerators. There is no clearly established boundary between refractory and non-refractory materials, though a practical requirement often cited is the ability of the material to withstand temperatures above 1100 °C without softening.
Condition referring to a disease that can no longer be controlled by the treatment program in effect. When a prostate cancer is said to be refractory, there is a need for some form of additional treatment.