Silica/silica composites through electrophoretic infiltration - Effect of processing conditions on densification of composites

Abstract

Ceramic matrix composites are high performance, high temperature materials of scientific as well as technical interest. During the last decade there has been great interest in development of oxide composites for structural as well as electrical applications. Silica/silica composites have been developed using electrophoretic infiltration. Matrix was derived from silica sol and colloidal silica sol having different process routes, solid content (24% - 35%), pH (2 - 3.5) and viscosity (55 -70 mpoise). The effect of densification parameters such as applied voltage, infiltration time, thickness of preform, viscosity, etc., have been studied and discussed. Composites processed at lower potential difference and under constant current density conditions yield better matrix microstructure and particle bonding, as well as interlaminar bonding. The composites fabricated with colloidal silica sol exhibit 60% sintered density.