High temperature calcination enhances the strength
of SiC preform by virtue of the generated SiO2 layer on
SiC. Too high temperature induces the formation of
obturated pores, which are difficult to be infiltrated. A
better calcination condition is found to be at 1 100 °C for
8 h in vacuum [8]. The disadvantage is that chemical
reaction between Al alloys and SiO2 film will reduce the
thermal properties.