Ultralight and high-strength bulk alumina/zirconia composite ceramic foams through direct foaming method

Abstract The mechanical strength of highly porous ceramic foamsshows significant attenuation with the increase of porosity, especially for ceramic foamswith very high porositylevel above 95%. Ultra-light bulk composite ceramic foamswere fabricated via introducing 20 wt% zirconia in alumina-based cell wall, aiming at improving mechanical strength of alumina based ceramic foams. The preparation and stability of alumina and zirconia particles synergistically stabilized foams were investigated. The obtained bulk ceramic foamsmanifested an exciting combination of both high porosityabove 96% and excellent specific compressive strength, due to their closed pore structure, defect-free cell wall with uniform thickness, and uniformly distributed zirconia grains in alumina matrix. The alumina/zirconia composite ceramic foamswith porosityof 96.7% exhibited compressive strength of 1.11 ± 0.07 MPa, which was much higher than that of alumina ceramic foamsin the case of same porosity.