Characterization of SiC- and TiN-particle-reinforced Si3N4 composites

The purpose of this study was to investigate the dependence of TiN particle (0,8 mu m) and SiC particle (0,2 mu m) dispersions on the mechanical prope rties in commercially available Si3N4. It was found that the alpha-->beta-S i3N4 transformation is dependent on the sintering temperature as well as on the low secondary phase content. Compared to SiC powder, TIN powder stabil izes the desired beta-Si3N4 phase in the composites and hence only a slight decrease of bending strength was observed. Up to 5 vol. % dispersion conte nt, the fracture toughness was found to be constant at 6,8 MPa MPa.m(1/2). With increasing SiC content, the bending strength clearly decreases.