Silica xerogels were prepared by sol-gel process and non-supercritical drying. Two kinds of
reinforcements, SiC whisker and short carbon fiber (CF), were chosen to control the shrinkage during
drying process and improve the mechanical properties of xerogels. Microstructure and mechanical
properties of samples were examined. It was found that the addition of SiC whisker could greatly improve
the elastic modulus of silica xerogels, while short CF could prominently decrease the volume shrinkage
ratio but could not improve the elastic modulus. Analysis showed that the difference between the two
reinforcement mechanisms was caused by the interface and the size of the doped fiber and whisker.
Microstructure and mechanical properties of slip cast sol-gel derived mullite ceramics
