A thin upper layer on a SiC-A12O3 porous substrate was formed by spray deposition of a Si-C composite or SiC fine powder 55.0 wt% total powder suspension. The formation of a compact layer of Si3N4 whisker or a SiC smaller pore size than the porous substrate was obtained under thermal treatment up to 1400°C for 3–4 h in a nitrogen or argon gas environment, respectively. SEM microstructure observations and a qualitative (DRX-EDAX) analysis of both sintered porous bodies were performanced to confirm the nature of both layers.