A microstructure study of Ni/Al2O3 composite ceramics

Ni/Al2O3 composites and pure alumina were prepared using SPS and HP methods. The toughness increases after the addition of Ni particles although relative density and bending strength decreased. The mechanical properties of SPS specimen are better than those of HP specimen. Microstructure observation shows addition of Ni phase and the rapid sintering rate of SPS method decrease alumina grains size, increase pore density and dislocation density. Ni grains distribute both inside alumina grains and at grain boundaries. Ni grains are most single crystals and remain metallic after sintering process.