ASSOCIATION OF THE CVI PROCESS AND OF THE USE OF POLYSILAZANE PRECURSOR FOR THE ELABORATION OF CERAMIC-MATRIX COMPOSITES REINFORCED BY CONTINUOUS FIBERS

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 ti me of elaboration than for CVI alone and, secondly higher mechanical p roperties than those resulting from a conventional use of the precurso r. Composites with mechanical properties comparable to those of compos ites entirely obtained by CVI of SiC have been realised The flexual st rength of these materials is about 400 MPa, whereas that of composites resulting from a conventional use of the same polysilazane does not e xceed 200 MPa.