Corrosion behavior of HVOF Inconel 625 coating in the simulated marine environment

High velocity oxygen fuel (HVOF) spraying process is commonly used to produce superalloy coatings. Inconel 625 coating was prepared on Q235B low carbon steel by HVOF. A series of experiments were conducted to examine the surface and corrosion resistance properties of Inconel 625 HVOF coating. In this paper, potentiodynamic polarization tests and electrochemical impedance spectroscopy (EIS) tests were carried out to evaluate the corrosion resistance of Inconel 625 coating under simulated marine environment. The experimental results showed that Inconel 625 coating revealed low porosity and desired coating thickness. Shift in the corrosion potential (E_corr) towards the noble direction combined with much low corrosion current density (i_corr) indicating a significant improvement of HVOF Inconel 625 coating compared with the substrate.