Pulsed plasma nitriding of high velocity oxy-fuel sprayed Inconel 625 coatings

A hardening of high velocity oxy-fuel sprayed Inconel 625 coating systems was performed by pulsed plasma nitriding treatment. After deposition of an Inconel 625 coating, samples were pulsed plasma nitrided at 520 °C for 12 h in a gas ratio of 3:1 N 2 and H 2 under a constant pressure of 2.5 × 10 2 Pa. Pulsed plasma nitriding improved the microhardness of the high velocity oxy-fuel sprayed Inconel 625 coating from 355 to 401 HV 0.05 . The high velocity oxy-fuel-sprayed Inconel 625 coating after pulsed plasma nitriding process showed excellent corrosion resistance as well as a reduction of both the friction coefficient and wear rate during the sliding phase in a 3.5 wt.% NaCl solution against sliding action of Al 2 O 3 ball.