Influence of powder characteristics on the electrical resistivity of SiC ceramics

Four types of commercially available SiC powders were hot-pressed with 1 wt % Dy2O3-AlN additives in a 3:2 molar ratio. Three submicron-sized SiC powders could be densified so as to have a relative density higher than 98%, whereas a micron-sized SiC powder showed limited densification up to 93.5%. SiC ceramics fabricated from beta-SiC powders exhibited electrical resistivities (similar to 10(-1) Omega.cm) that were lower than those from alpha-SiC powders (similar to 10(1) Omega.cm). The lower electrical resistivity of the SiC ceramics fabricated from beta-SiC powders could be attributed to a higher carrier density and enhanced charge mobility when compared to the SiC ceramics from alpha-SiC powders. (C) 2012 The Ceramic Society of Japan. All rights reserved.