Cc. Chiu et al., SURFACE OXIDATION AND ITS EFFECT ON THE OBSERVED ELASTIC-MODULUS OF SIC WHISKER AL2O3 COMPOSITES/, Journal of composite materials, 28(1), 1994, pp. 2-21
This article presents an analysis of the 27 wt. % SiC whisker/Al2O3 co
mposites exposed to air for periods up to 180 hours at 1100 degrees C
to 1450 degrees C. Experimental results indicate that SiC whisker reac
ts with oxygen and alumina to produce a mullite-rich surface layer on
tested composite specimens. The surface oxidation reaction degrades th
e observed elastic moduli of specimens. A theoretical analysis based o
n the Bernoulli-Euler beam equation shows that the surface layer has l
ower elastic modulus than the unreacted core.