Fabrication of SiC body by microwave sintering process

In the present study, SiC samples with 3, 5, 7.5 and 10 wt% Al₂O₃–Y₂O₃ as additives were made by powder metallurgy method, then sintering was performed by microwave-assisted process. β–SiC samples sintering was performed for 100 min. The highest sintered relative density 91.06% was achieved at 10 wt% additives content. The maximum values of hardness and toughness were up to 23.3 GPa and 6.14 MPa.m^− 1/2. α–SiC and α–SiC/β–SiC samples sintering was performed for 120 min. The maximum value of density and hardness were up to 96.38% T.D and 24.88 GPa in α–SiC with 7.5 wt% additives, whereas the highest toughness was achieved at 10 wt% additives content in β–SiC samples. The α–SiC samples structure resulted in equiaxed grain morphology, while β–SiC samples yielded elongated grains. In samples contained α–SiC/β–SiC a significant reduction in grain size occurred by increasing α–SiC. Results showed that with increasing oxide, the thermal conductivity decreases and electrical resistance increases, also increasing the time of sintering increases thermal conductivity and electrical resistance.