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 processing techniques, in order to produce different microstructures while keeping a uniform distribution of the SiC particles in the alumina matrix. Basically, this study used three techniques i.e. mechanical mixture of powders, the use of an inorganic precursor for alumina precipitated onto SiC particles and the use of different polymeric precursors for SiC precipitated on alumina particles. Hot pressing at 1700 degrees C was necessary to produce fully dense nanocomposites. The alumina precursor route produced the smallest matrix gr ain size and the SiC precursor route produced the smallest reinforcement particle size. Despite the differences in microstructure between the nanocomposites, the flexure strength remained the same, and no distinct improvement over the monolithic alumina was observed. The fracture mode, however, changed from intergranular to transgranular with the presence of the SiC particles. (C) 1997 Elsevier Science Limited.