パルス通電焼結法による珪化物基超高温材料の作製

抄録

Silicides are receiving much attention as high-temperature materials having extremely-high oxidation resistance based on the formation of a protective silica scale. However, they are limited in application because of their brittleness. Therefore, the use of them as coatings on refractory metals, which have poor oxidation resistance, is strongly desired.

Spark plasma sintering is well known as a useful and simple sintering method. However, the effect of spark between particles on sintering has not been clarified yet. In the present study, sintering behavior of electrically-conductive materials (some metal silicides such as MoSi₂, FeSi₂, CoSi₂, CrSi₂, and VSi₂) was studied. Based on the results, it was concluded that with sintering of the conductive materials the spark effect was exhibited. In addition, fabrication of dense disilicides can be easily achieved by the application of spark plasma sintering method.

The mechanism of oxidation of silicides has not been clarified. In other words, it is not well-known that a protective silica scale is formed in what kind of silicides. This review focuses on the classification of oxidation behavior in silicides.