The oxidation behavior and its effect on the mechanical properties of fibrous monolith Si3N4/BN after exposure to air at temperatures ranging from 1000° to 1400°C for up to 20 h were investigated. After exposure at 1000°C, only the BN cell boundary was oxidized, forming a B2O3 liquid phase. With increasing exposure temperature, the Si3N4 cells began to oxidize, forming crystalline Y2Si2O7, SiO2, and silicate glass. However, in this case, a weight loss was observed due to extensive vaporization of the B2O3 liquid. After exposure at 1400°C, large Y2Si2O7 crystals with a glassy phase formed near the BN cell boundaries. The oxidation behavior significantly affected the mechanical properties of the fibrous monolith. The flexural strength and work-of-fracture decreased with increasing exposure temperature, while the noncatastrophic failure was maintained.
|Number of pages||3|
|Journal||Journal of the American Ceramic Society|
|Publication status||Published - 2002 Dec 1|
ASJC Scopus subject areas
- Ceramics and Composites
- Materials Chemistry