Microstructure and performance of functionally gradient Ti(C, N)-based cermets fabricated by low-pressure carburizing treatment during liquid phase sintering

摘要

Functionally graded Ti(C, N)-based cermets were prepared by a cost-effective and environment-friendly procedure which combined vacuum sintering with low-pressure carburizing treatment during liquid phase sintering stage in one cycle. The prepared cermets were investigated using scanning electron microscope (SEM), energy dispersive X-ray analysis (EDX), electron probe microanalysis (EPMA) and X-ray diffraction (XRD), which revealed that a considerable thick nickel-deficient layer was introduced due to the fast diffusion of carbon inwards at 1400 C. Moreover, the thickness of binder-deficient layer of graded cermets gradually increased with increasing carburizing time, but the amplitude of deficient nickel of the original surface dramatically decreased. Typically, Ti(C, N)-based cermets carburized for 40 min possessed a 600 gm deep nickel-deficient layer, and showed excellent mechanical properties with surface hardness of 1753(-73)(+63) HV and TRS of 2092(-146)(+117) 6 MPa.