[T15] Hard Materials

[16P-T15-08] Nano-Micro Hardness of the Mo₂NiB₂-Ni Cermets

*S. Ichijo¹, Y. Harada¹, E. Takahashi¹, T. Hirano¹, R. Maki², S. Maruyama¹ (1.Tokyo City University, Japan, 2.Okayama University of Science, Japan)

キーワード：Cermet, Hardness, Nano indentation, Boride

Mo₂NiB₂-Ni cermets, one of the boride-base cermet, have been investigated, aiming to improve its mechanical properties through doping transition metals, such as Cr and V.By adding Cr and V to the Mo₂NiB₂-Ni cermet, the crystal structure of the Mo₂NiB₂ is changed from orthorhombic-type to tetragonal-type, and mechanical properties show enhancement. However, details of structure deformation and the mechanical properties of Mo₂NiB₂ phases still need to be discovered. In this study, we performed a nano-indentation measurement to investigate the hardness of the Mo₂NiB₂ phases.Cr and V doped complex boride base cermets with tetragonal structure-type and non-doped Mo₂NiB₂-Ni cermet with orthorhombic-type structure were sintered using Reaction Boronising Sintering method proposed K. Takagi. According to the nano-indentation measurement, the hardness of the tetragonal phase exhibited 25 ~ 28 GPa, while that of the orthorhombic phase showed 20 ~ 23 GPa.Detailed results, including microstructure observation, will be presented on the day.