Spark-plasma-sintering consolidation of SiC-whisker-reinforced mullite composites

Spark plasma sintering was applied to consolidate a series of SiC-whisker-reinforced mullite-matrix composites containing up to 30 vol% of whiskers. Bodies with relative densities higher than 99% were obtained at 1400degreesC, using a holding time of 3 min and a uniaxial pressure of 50 MPa. The analysis of densification kinetics revealed that a shrinkage rate of about 10(-3) s(-1) was obtained even with a high whisker load, showing that the spark plasma sintering process is a rapid technique for fabricating whisker composites. The very rapid densification that occurs during spark plasma sintering allows little time for growth of the matrix grains. This, in turn, leads to improved mechanical properties.