OXIDATION PROTECTION FOR CARBON-FIBER COMPOSITES

Carbon fibre-reinforced ceramic matrix composites are promising candid ate materials for high-temperature structural applications such as gas turbine blades. In oxidizing environments at temperatures above 400 d egrees C, however, carbon fibres are rapidly oxidized. There is, there fore, a need to coat the composite in order to protect it against oxid ation. This review identifies the requirements of an effective oxidati on protection system for carbon fibre-reinforced ceramics and summariz es the work which has been carried out towards this goal over the last 50 years. The most prom ising coatings are those com posed of several ceramic layers designed to protect against erosion, spallation and co rrosion, in addition to possessing a self-healing capability by the fo rmation of glassy phases on exposure to oxygen.