Densification process in fabrication of PSZ-Ti composites by spark plasma sintering technique

Densification process in the fabrication of partially stabilized zirconia (PSZ) - pure titanium (Ti) composites by spark plasma sintering (SPS) technique was discussed. The sintering schedule to fabricate a fully-sintered compact was terminated at given stages, and semi-sintered compacts were fabricated to examine their densification process from viewpoints of their microstructure, density and creation of reaction phases. The densification of PSZ-Ti composites progressed in an intermediate manner between the monolithic Ti and PSZ at an early stage of sintering, and then became slower than the monolithic Ti and PSZ at the final stage. Moreover, the sintering was slower in the Ti-rich composite than in the PSZ-rich composite. According to XRD analysis, Ti phase in the PSZ-Ti composites oxidized over 800 °C, irrespective of Ti volume fraction. These results revealed that the creation of Ti oxide due to element diffusion and the difference in powder size of PSZ and Ti affected the densification process of PSZ-Ti composites.