Porous silicon carbide membrane supports were prepared using alumina and yttria additives (1-4 wt%) with various weight ratios of Al2O3/Y2O3 (23/77-60/40) and sintering at 1500-1800 degrees C. The relationships between the processing factors and the porosity, pore size and microstructure were examined. Variation of the sintering temperature, the amount of additive used and the ratio of Al2O3/Y2O3 were found to be effective for control of the pore size and microstructure. The pore size and grain size of membrane support with 1 wt% additive increased with the sintering temperature. For SiC membrane supports containing 4 wt% additive, pore size and grain size were dependent on the alumina ratio in additive. Smaller grains and fine pores around 200-300 nm were detected for specimens with higher Al2O3 content (60/40) in the additive. In contrast, for specimens with low Al2O3 content (23/77) in the additive, the grain and pore sizes were enlarged. This difference was attributed to the effect of Al2O3 content on the temperatures of liquid phase formation during sintering. (C) 2009 Elsevier B.V. All rights reserved.