Development of High Strength Mo_2NiB_2 Ternary Boride Base Cermets Produced by Reaction Boronizing Sintering

摘要

The effects of V substitution for Cr to the sintering behavior of Cr containing Mo_2NiB_2 ternary boride base cermets and Mn addition to the mechanical properties and microstructure of the Cr and V containing cermets were investigated by using Ni-5.0B-51.0Mo-(l7.5-x)Cr-xV (mass%) and Ni-5.0B-51.0Mo-12.5Cr-5.0V-(0-1.5)Mn (mass%) model cermets. 10mass%V substitution for Cr in the Cr containing cermets markedly improved transverse rupture strength and hardness from 2.27 to 2.94GPa and from 85.3 to 87.2Ra respectively and refined the microstructure by retarding the progress of sintering especially at liquid phase sintering stage. Small amount of Mn addition to the Cr and V containing Mo_2NiB_2 base cermets significantly improved the sinterability and increased the mechanical properties of the cermets.