Liquid-Phase Sintered Silicon Carbide with Aluminum Nitride and Rare-Earth Oxide Additives
SiC was sintered with AlN and Y2O3 as sintering additives by spark plasma sintering (SPS). Using nano-sized β-SiC powder as the starting material, the sintered density reached about 95% of theoretical at 1800-2000oC for 10min. The β to α phase transformation of SiC was not found by XRD. The secondary phase such as Y2O3 decreased as the firing temperature was elevated, and β-SiC monophase was identified at 2000oC. It seems that the residual intergranular glassy phase is present between the SiC grains. Significant SiC grain growth was observed at 1800-1900oC by SEM. The grain size decreased with increasing amount of AlN additive. The maximum value of flexural strength of the sample reached approximately 800MPa. These results are discussed on the basis of the liquid-phase sintering mechanism in AlN-Y2O3 and Al2O3-Y2O3 systems.
T. Ohji, T. Sekino and K. Niihara
M. Hotta et al., "Liquid-Phase Sintered Silicon Carbide with Aluminum Nitride and Rare-Earth Oxide Additives", Key Engineering Materials, Vols. 317-318, pp. 111-114, 2006