Microwave-enhaced chemical vapour infiltration (MECVI) has been used to produce silicon carbide fibre reinforced silicon carbide composites in a matter of hours. The process works by thermally breaking down a gas to yield the SiC matrix material inside a SiC fibre preform. The use of microwave heating in the process working from the inside out - this has yielded samples within about 30 hours; conventional CVI can take as long as 3 months. Two pre-infiltration techniques, vacuum bagging (VB) and electrophoretic infiltration (EPI), have also been investigated. Both techniques deposit SiC powder into the initial SiC fibre preform reducing the void space to be filled by the MECVI process. The results indicate that both approaches result in an enhanced initial density and a consequent significant reduction in the time required for the final MECI step.
