High Resolution Electron Microscopic Observation on Interfacial Structures of SiC Whisker/Si₃N₄ Composite Ceramics

Abstract

Microstructures of SiC whisker/(Si₂N₄-4, 8, 12mol%Y₂O₃ 6mol%Al₂O₃) composite ceramics were examined by high-resolution transmission electron microscope. No evidence of interfacial reaction both between SiC whisker and grain boundary phase and between SiC whisker and Si₃N₄ was observed, irrespective of Y₂O₃ content. Therefore, the conclusion in the previous study that the variation of the mechanical properties of SiC whisker/Si₃N₄ composite ceramics with increasing Y₂O₃ content was mainly due to the variation or change in the size of acicular Si₃N₄ grains and the kinds of the grain boundary phase was considered to be correct.