Effect of Silica Addition on Ceramic Layer in Centrifugal-Thermit Reaction

抄録

Ceramic lined steel pipe is produced by a thermit process under a centrifugal force. A powdery mixture of ferric oxide and aluminum with silica is used. The addition of silica material has an important role for densification of the ceramic layer formed inside the pipe. It is found that the silicate materials of 2FeO·SiO₂ and 3Al₂O₃·2SiO₂ in amorphous state significantly extend the liquid phase longer and improve the layer structure density as cooling proceeds. Additionally, it is proposed that a mechanism of solidification and densification progresses through four steps for the ceramic layer formation.