Effect of nitrogen and secondary carbide on the microstructure and properties of (Ti0.93W0.07)C–Ni cermets

Abstract

Solid-solution powders of (Ti0.93W0.07)C and (Ti0.93W0.07)(C0.7N0.3) were synthesized via high-energy ball milling and carbothermal reduction processes. After blending powders with Ni and other carbides, cermets were prepared by a blending and sintering process at 1510°C for 1h. We observed a typical core/rim structure consisting of solid solution phases. We also found that secondary carbide and nitrogen have a remarkable influence on the cermet microstructures. Further, with an increase in the Mo2C content, the mechanical properties of these cermets were enhanced significantly; the hardness of carbide and carbonitride cermets increased from 9.3 and 12.7 to 12.9 and 13.9GPa, respectively. All results are discussed in terms of the thermodynamic stability and dissolution behavior of the constituent carbides and carbonitride.