Quick introduction: Foundry

Non-contact melting with porous ceramic crucibles

© Fraunhofer IKTS
Floating aluminium melt on a nitrogen gas bed, crucible temperature approx. 900 °C.

When melting reactive, corrosive or high-purity metals, reactions with the lining of the crucible are undesirable, as these lead to impurities in the metals. To avoid these problems, the Fraunhofer IKTS has developed a non-contact melting process based on porous silicon carbide ceramics. With the help of these ceramics, two functions can be realized simultaneously. Firstly, a homogeneous gas cushion can be created between the melt and the crucible wall by flowing a gas through the ceramics. This means that the metals have no direct contact with the crucible. On the other hand, it is possible to heat the metal quickly by direct electrical heating of the ceramics and the gas flowing through it. Temperatures and different gas atmospheres are precisely adjustable.