This work investigated two alternative processing routes for the preparation Al2O3/SiC nanocomposites. One used a polymeric precursor for the Sie phase (polysilastyrene) and commercial alumina powder. The materials were mixed in toluene, dried and heated to 1500 degrees C to crystallize the SiC phase. The resultant powder consisted of SiC particles (50-300nm in size) distributed at the surface of the alumina particles. The second processing route utilized an inorganic precursor for alumina (aluminum nitrate). This precursor was dissolved in water in the presence of nano-sized commercial SiC and urea. Controlled heat treatments, at low and high temperatures, promoted the precipitation of an alumina phase onto the SiC particles. In both processing routes, the material was milled and hot pressed at 1700 degrees C to achieved full densification. TEM and XRD analysis were used to characterize the powders and the sintered pieces. Samples prepared from conventional mixture of commercial powders were used as the control. It is shown that the use of chemical precursors produced distinctive microstructures, with different matrix grain sizes, SiC particle sizes and location in the matrix as compared to the control material.
