COATING CERAMIC COMPOSITES BY A LASER IN-SITU REACTION TECHNIQUE

A continuous Al2O3 coating on SiC/Al2O3 ceramic composites for heat ex changer applications can be achieved using a laser-assisted in-situ re action technique. Deposition of a bond coat of either aluminum or tita nium using physical vapor deposition prior to laser treatment is essen tial for coating adherence. The in-situ transformation of the precurso r aluminum powder delivered at the laser-substrate interaction zone in an oxygen atmosphere results in the deposition of the Al2O3 layer on the SiC/Al2O3 composite substrate.