Effects of Mechanical Ball Milling and Calcination on the Mechanical Properties of Mo₂NiB₂-Ni cermets

Abstract

Mo₂NiB₂-Ni cermets have been sintered using “Reaction Boronising Sintering (RBS)” proposed by K. Takagi. In RBS, the generation of an inhomogeneous microstructure of the boride phase occurs. In this study, the calcination and mechanical milling processes were introduced into the sintering process of Mo₂NiB₂-Ni cermets to separate the phase formation and densification and refine the microstructure. According to SEM observations, the porosity and grain size was reduced after calcination. It was also found that cermets with higher transverse rupture strength (TRS) and hardness were obtained. In addition, changes in the sintering process resulted in lower optimum sintering temperatures for obtaining these properties.