Gas pressure sintering of SiC–AlN composites in nitrogen atmosphere

The gas pressure sintering behaviour of SiC–5–25 wt.% AlN composites was studied. Sintering temperature was varied from 1700–1950 °C under a nitrogen pressure of six bar at the final sintering temperature. Pore-free dense product was achieved for the sample of composition SiC–25 wt.% AlN sintered at 1950 °C. XRD patterns revealed a gradual transformation of cubic SiC to hexagonal form with increasing sintering temperature from 1700 to 1950 °C along with the densification of the specimen and solid solution hardening. Hardness of the sample sintered at 1950 °C was found to increase with increasing AlN content from 21.26 to 25.36 GPa.