Sintering, mechanical, and oxidation properties of TiC-Ni-Mo cermets obtained from ultra-fine TiC powders

Abstract

This paper studies the sintering, microstructure, mechanical, and oxidation properties of TiC-Ni-Mo cermets obtained from ultra-fine TiC powders. The TiC powders were synthesized from a novel carbon coated precursors carbothermal reduction method. The weight percentage of TiC was 75 wt%, the Mo phase increased from 0 to 20 wt%, and the Ni phase balanced the composition. At a sintering temperature of ∼1500 °C for 1 h with argon flowing, the utilization of the ultra-fine TiC powders results in high relative density (>98%), fine microstructure, and good mechanical properties. The Mo substitution can further: (1) enhance the relative density to above 99.5%; (2) lead to the formation of core-rim structure; (3) refine the grain size from ∼1.3 ± 0.1 to ∼1.0 ± 0.1 μm with Mo content at 10 wt%; (4) enhance the hardness and fracture toughness to 14.9 ± 1.2 GPa and 15.4 ± 1.1 MPa m1/2 with Mo content at 10 wt%; (5) greatly enhance the oxidation resistance with 20 wt% Mo substitution.