Evaluation of the Surface Integrity of Titanium Nitride Coating Deposited on the Ni-Ti Substrate Through the Near-Dry Electrical Discharge Surface Coating Process

Having superior mechanical properties, nickel-titanium (Ni-Ti) based shape memory alloys are extensively used to make bio-implants. The existing literature suggests several surface modification techniques, including surface coating, for improving the bio-compatibility by reducing leakage of nickel from surface layers. Herein, an environmentally-friendly surface coating method, based on the concept of near-dry electric discharge machining (ND-EDM) process, was explored to deposit the titanium nitride (TiN) layer. Repeated spark discharges occurring in a two-phase dielectric medium of water and nitrogen gas were used for depositing the layer. The effect of process parameters like peak-current and pulse-on time on the surface integrity of deposited layers was evaluated. The deposited surfaces were characterized using the X-Rays diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), and atomic force microscopy (AFM) techniques. The results show that the TiN layer can successfully be deposited onto Ni-Ti substrate.

Automated summary

A study on environmentally-friendly surface coating method based on near-dry electric discharge machining (ND-EDM) for depositing TiN layer onto Ni-Ti substrate was conducted. The effects of process parameters on surface integrity of deposited layers were evaluated, and the deposited surfaces were characterized using XRD, FE-SEM, and AFM techniques. The results demonstrated successful deposition of TiN layer onto Ni-Ti substrate.