Defects in Silicon Carbide Whiskers

Defects in silicon carbide whiskers made from rice hulls were identified and analyzed using transmission electron microscopy. The whiskers were characterized by a high density of planar faults lying on close-packed planes perpendicular to the whisker axis. The faulting resulted in complex mixtures of β and α polytypes arranged in thin lamellae normal to the whisker axis. Core regions of whiskers were often filled with small cavities ranging in size from 1 to 20 nm. Partial dislocations accompanied the cavities and were analyzed through specimen tilting experiments.