Fabrication and Mechanical Properties of Mo-Al2O3 Cermets by Using Ultrafine Molybdenum and Nano-sized Alumina Powders

To improve the performance of Mo-based cermets, Mo-(Ni)-Al 2 O 3 cermets were prepared with raw materials of nano-sized Al 2 O 3 powder. The effects of Al 2 O 3 and Ni additions on the densification behavior, microstructure, bending strength, and hardness of the Mo-(Ni)-Al 2 O 3 cermets were experimentally analyzed. The results showed the content of Al 2 O 3 had a great influence on the degree of densification of Mo-Al 2 O 3 cermets at the sintering temperature of 1600°C. In addition, the Al 2 O 3 particles were distributed evenly in the matrix of Mo-based cermets, which refined the grains of Mo and increased the hardness of cermets. Because of the weak interfacial bonding strength between Al 2 O 3 ceramic phase and Mo metal phase, the bending strength decreased continuously with increasing Al 2 O 3 content. However, Ni addition improved the wetting and adhesion of Al 2 O 3 and Mo. With the addition of Ni, the relative density increased, and thus hardness and bending strength were improved.