Effects of foaming temperature on the preparation and microstructure of alumina foams

Abstract

Alumina foams with porosity of 94.5–93.1vol% were obtained by the thermo-foaming of powder dispersions in molten sucrose at 130°C. Effects of foaming temperature on the preparation and microstructure of the alumina foams were investigated. Low foaming temperature resulting in high viscosity facilitated the stability of the bubbles generated through condensation reactions in molten sucrose. The alumina foams showed interconnected cellular microstructure and the cells had a near spherical morphology. The cell size distribution was bimodal as a whole and the window size was unimodal in various alumina to sucrose (A/S) weight ratios. The mean cell size was varied from 740 to 1640μm and the mean window size was between 89 and 137μm. Compressive strength of the obtained alumina foams was maximum when the weight ratio of A/S is 1.4, the density was 0.272g/cm3 and the compressive strength reached 1.32MPa.