INFLUENCE OF PROCESSING ON THE MICROSTRUCTURAL DEVELOPMENT AND FLEXURE STRENGTH OF AL2O3 SIC NANOCOMPOSITES/

Alumina/10 wt% SiC nanocomposites were prepared by using a number of p rocessing techniques, in order to produce different microstructures wh ile keeping a uniform distribution of the SiC particles in the alumina matrix. Basically, this study used three techniques i.e. mechanical m ixture of powders, the use of an inorganic precursor for alumina preci pitated onto SiC particles and the use of different polymeric precurso rs for SiC precipitated on alumina particles. Hot pressing at 1700 deg rees C was necessary to produce fully dense nanocomposites. The alumin a precursor route produced the smallest matrix gr ain size and the SiC precursor route produced the smallest reinforcement particle size. De spite the differences in microstructure between the nanocomposites, th e flexure strength remained the same, and no distinct improvement over the monolithic alumina was observed. The fracture mode, however, chan ged from intergranular to transgranular with the presence of the SiC p articles. (C) 1997 Elsevier Science Limited.