Association of the CVI process and of the use of polysilazane precursor for the elaboration of ceramic matrix composites reinforced by continuous fibres

Abstract

A new process route for ceramic composites, associating CVI of SiC and impregnation and pyrolysis cycles with a polysilazane precursor, has been developed. The interest of this process is, firstly, a shorter time of elaboration than for CVI alone and, secondly higher mechanical properties than those resulting from a conventional use of the precursor. Composites with mechanical properties comparable to those of composites entirely obtained by CVI of SiC have been realised. The flexual strength of these materials is about 400 MPa, whereas that of composites resulting from a conventional use of the same polysilazane does not exceed 200 MPa. © 1995.