Gel-casting of porous alumina ceramics with high mechanical strength

Abstract

Alumina foams with high mechanical strength were prepared by means of gel-casting. After preparation of gel-cast raw segments, they were dried in a controlled humidity chamber. Samples were sintered at a temperature of 1 350 °C held for 2 h. The effects of additives and alumina loading on the initial suspension behavior, ultimate porosity, relative density, and mechanical strength of sintered samples were investigated by means of different techniques including densitometry, scanning electron microscopy and compressive strength measurements. Results showed that the optimal conditions for the preparation of desired alumina foam are 0.03 wt.% of sodium dodecyl sulfate, 1 g L−1 of initiator and 8.3 mL L−1 of catalyst for suspensions with 0.8 – 1 wt.% of Tiron and 70 % of alumina loading. The value of compressive strength was measured as high as 25.62 MPa for alumina foam with very low relative density of 19.27 %.