Combustion synthesis and densification of Cr-Al(Cr)2O3 cermets

Cr-Al(Cr)(2)O-3 cermets have been successfully produced by combustion synthesis, through changing the composition of reaction system and controlling the solidification process. The microstructures of the cermets were characterized by dispersive sub-micron scale Cr particles in ceramic matrix. The effects of polymer addition and system composition on the microstructure of the cermets and combustion synthesis procedure were investigated. The results show that the igniting temperature and time of Al-Cr2O3-Al2O3 system decrease evidently with polymer addition. Also, the polymer addition could make Cr particles more uniformly distribute in the ceramic matrix. By adding the diluent Al2O3 and excessive Cr2O3, the size of Cr particles could be decreased, and the matrix of the cermets are changed from pure Al2O3 to Al2O3 and (Al, Cr)(2)O-3 mixture. The densification of Cr-Al(Cr)(2)O-3 cermets is achieved by applying a lower pressure on the synthesized melt.