Controlling particle size distribution for preparing multi-layer structure compacts

Ceramic compacts which have a self-arrangement characteristic according to surface properties in moulding process were made. Two types of SiO2 powder, of which particle sizes are different from each other in average, went through the surface treatment through stearic acid and ABDM (alkyl benzyl dimethyl ammonium chloride) to have hydrophobic and hydrophilic features, respectively. This process is to induce diverse movements to several directions by surface properties in a slip. In gypsum mould, it is shown that different kinds of particles have relatively different movements in the process of squeeze casting to make compacts, that is, particles with hydrophobic features on the surface tend to move to the surface of the gypsum and particles with hydrophilic features on its surface show a tendency to be distributed evenly in the slip. Finally, on the surface of the compact are mainly hydrophobic particles, and hydrophilic particles come to exist mainly in the inside of the compact, and this demonstrates the fact that by modifying surface properties the particles distribution can be controlled artificially, and this study observed the fact through based on the experimental results above.