Alumina–nickel composites densified by spark plasma sintering

Alumina–nickel composites were prepared by spark plasma sintering (SPS) with sintering temperatures between 1000 °C and 1270 °C at a heating rate of 200 °C/min. The results showed that the nickel phase was uniformly dispersed in an alumina matrix. The alumina grain sizes increased with increasing sintering temperature and holding time. The relative density of the samples showed that, without holding time, the composites fabricated by SPS could not be consolidated to full density. With a 10 min holding time, the composites, in which grain size of Al2O3 was 0.5–1.0 μm, were consolidated to full density at 1170 °C. For dense composites, the fracture toughness of the composites was 3.84 MPa·m1/2, higher than that of monolithic Al2O3 ceramics.