Plasma-carburization of nickel-based self-fluxing alloy

Surface hardening of Ni-based self-fluxing alloy was carried out using plasma-carburization. The carburization was performed utilizing methane glow discharge plasma on sintered Ni-based self-fluxing alloy (METCO 16C) at 977 °C and 1065 °C for 3.6 ks. The carburized surfaces were characterized by employing optical microscopy, scanning electron microscopy (SEM), electron probe microanalysis (EPMA), transmission electron microscopy and Vickers micro-hardness testing. The SEM and EPMA micrographs show that the thickness of the carburized hard layer increased with increasing temperature, to a depth of approximately 120-200 μm. Hard chromium carbide (Cr3C2) was found to precipitate near the surface on carburization at 977 °C more than at 1065 °C. Cr3C2 contributes to the surface hardening.