Because of the high temperature of an industrial kiln, refractory materials must have strong temperature resistance, high strength, and other excellent thermal and mechanical properties to ensure safe and reliable operation.
The following are the general materials for kiln accessories:
Cordierite, mullite, silicon carbide, silicon nitride, corundum mullite, and other similar materials.
Cordierite and mullite materials are appropriate for applications requiring low temperature, low operating stress, and good thermal shock resistance. Also, cordierite and mullite are frequently used in the shed board, column, and backing plate of a low temperature rapid fire kiln.
Silicon carbide materials are well suited to handle low temperatures, strong working stresses, and possess high thermal conductivity, and thermal shock resistance. There are four types of silicon carbide materials: oxide-bonded, reaction-sintered, recrystallized silicon carbide materials, and nitride-bonded.
Oxide-bonded silicon carbide is used for kiln furniture in the low and medium ranges. The porosity of reaction-sintered silicon carbide is almost zero, it has very high strength, but it is limited to temperatures of 1350°C or lower; it is used for low temperature fast firing furnaces.
Recrystallized silicon carbide has a good dimensional stability and high temperature bearing capacity; occasionally it can be used for temperatures higher than 1350°C.
Lastly, corundum mullite is utilized in high-calcination-temperature ceramics such as alumina ceramics and ferrite ceramics.
