Use of electrophoretic deposition in the processing of fibre reinforced ceramic and glass matrix composites: a review

Electrophoretic deposition (EPD) is a simple and cost-effective method for fabricating high-quality 'green' composite bodies which, after a suitable high-temperature treatment, can be densified to a composite with improved properties. In this contribution, we describe the use of EPD technique in the fabrication of fibre reinforced composites, with an emphasis on composites with glass and ceramic matrices containing metallic or ceramic fibre fabric reinforcement. EPD has been used to infiltrate preforms with tight fibre weave architectures using different nanosized ceramic particles, including silica and boehmite sols, as well as dual-component sols of mullite composition. The principles of the EPD technique are briefly explained and the different factors affecting the EPD behaviour of ceramic sols and their optimisation to obtain high infiltration of the fibre preforms are considered. In particular, the EPD fabrication of a model alumina matrix composite reinforced by Ni-coated carbon fibres is presented. The pH of the solution and the applied voltage and deposition time are shown to have a strong influence on the quality of the infiltration. Good particle packing and a high solids-loading were achieved in most cases, producing a firm ceramic deposit which adhered to the fibres. Overall, the analysis of the published data and our own results demonstrate that EPD, being simple and inexpensive, provides an attractive alternative for ceramic infiltration and coating of fibre fabrics, even if they exhibit tight fibre weave architectures. The high-quality infiltrated fibre mats are suitable prepregs for the fabrication of advanced glass and ceramic matrix composites for use in heat-resistant, structural components. (C) 2001 Elsevier Science Ltd. All rights reserved.