Refractory Ceramic Fiber

Traditional  ceramic fibers  are made from inorganic materials, primarily aluminium oxide (Al2O3) and silicon dioxide (SiO2),with  very high thermostability. Under normal circumstances standard ceramic fiber can be applied at temperatures up to 1260 °C. By adding small amounts of, e.g., zirconium oxide (ZrO2) the application temperature can be increased to approx. 1600 °C.

Another new type of ceramic fiber  is a synthetic fibre made from alkaline earth silicates (basis :MgO-CaO). The fiber is soluble in the human body and consequently completely harmless from a health point of view. Such a fiber can normally be applied at temperatures up to approximately 1100 °C.

Ceramic fibre products are used in areas where good insulating properties at high temperatures are wanted – for packing and for expansion joints. If there is no mechanical wear, ceramic fibers can be used as the only refractory material in contact with high temperature processes, e.g. in kilns for heat treatment of metal, glass, etc.

Ceramic fiber is manufactured with different qualities depending on the production method: the spun and the blown fibre. A spun fibre yields the strongest, In most fields of application the two types of fibre function in the same way, and therefore the spun fiber is the most commonly used type.

Ceramic fiber blankets that are manufactured by placing the spun fiber on a conveyor belt. The belt speed and the thickness of the fibre layer determine the two most important quality parameters: density and thickness. The fibre blankets are frequently impregnated, felted, burnt and cut in order to achieve the well-known standard products. The standard fibre blankets are available in the density range 80 to 160 kg/m3 and in thicknesses from 6–50 mm.

Ceramic fiber are also available as massive boards, specially designed modules and wet blankets that are impregnated with a liquid making it possible to form the fibre products into the wanted shape that will remain after heating. Because of their unique (high temperature) properties ceramic fiber are rarely used in conventional thermal insulation applications in buildings.