Microstructure and bonding behavior on the interface of an induction-melted Ni-based alloy coating and AISI 4140 steel substrate

An induction-melted Ni-based alloy (NiCrBSi) coating on AISI 4140 steel was prepared using induction melting under different melting conditions. To determine the microstructure and bonding behavior of their interfaces, the techniques of micro-diffraction, X-ray mapping and wavelength dispersive spectrometry (WDS) were employed. The experimental results showed that a white zone appears on the Ni-based alloy side of the final interface, becoming wider and wider with increasing temperature and time, which was identified as a solid solution of γ-Ni at 1000 °C and 1180 °C. A higher heating temperature and time caused a more severe iron dilution in the Ni-based alloy and decreased the microhardness.