Minimum amount of nano-sized nickel particles to enhance the strength of alumina

Previous studies demonstrated that the strength of alumina could be enhanced by incorporating >5 vol.% nano-sized nickel particles. In the present study, the possibility of using a much smaller amount, <0.5 vol.%, of nano-sized Ni particles to improve the mechanical properties of Al2O3 is explored. As the Ni content is low, the densification of Al2O3 is affected little and the Ni inclusions remain small after pressureless sintering at 1600 °C. The presence of Ni inclusions can refine the matrix grains; the strength of Al2O3 matrix is consequently enhanced.