foam is an important engineering material because of its exceptional high-temperature stability, low thermal conductivity, good wear resistance, and stability in hostile chemical environment. In this work, foams were designed to control the microstructure, porosity, and cell size by varying different parameters such as the amount of amphiphile, solid loading, and stirring speed. Particle stabilized direct foaming technique was used and the particles were partially hydrophobized upon the adsorption of valeric acid on particles surface. The foam stability was drastically improved when these particles were irreversibly adsorbed at the air/water interface. However, there is still considerable ambiguity with regard to the effect of process parameters on the microstructure of particle-stabilized foam. In this study, the foam with open and closed-cell structure, cell size ranging from to having single strut wall and porosity from 75% to 93% were successfully fabricated by sintering at for 2 h in air.

In this study, a novel-processing route for fabricating microcellular zirconia ceramics has been developed. The proposed strategy for making the microcellula zirconia ceramics involved hollow microspheres as pore former. Compared to conventional dense microspheres pore former, well-defined pore structured zirconia ceramics were successfully fabricated. Effects of hollow microsphere content and sintering temperature on microstructure, porosity, pore distribution, and strength were investigated in the processing of microcellular zirconia ceramics.