Fabrication of silica matrix composite by chemical vapor infiltration

Nextel 480/silica composite was fabricated by chemical vapor infiltration. Tetraethylorthosilicate was used as precursor. The influence of the tetraethylorthosilicate temperature and deposition temperature on deposition rate and infiltration effect was investigated. The reason of the creation of the bottleneck effect and solid powder was analyzed. The phase of deposition production and the microstructure of the composite were characterized. The results indicated: the deposition rate increases markedly with the tetraethylorthosilicate temperature and deposition temperature increasing; the bottleneck effect results from the higher tetraethylorthosilicate concentration; the solid powder results from the higher deposition temperature; the production deposited from Tetraethylorthosilicate is amorphous silica; the silica deposited has the good thermal match with Nextel 480 fiber and no crack was found on the surface of silica matrix.