Magnesium alloy bipolar plates offer great advantage in weight reduction of polymer electrolyte membrane fuel cell. An attempt to improve the corrosion resistance and surface conductivity of magnesium alloy has been made by a medium electroless plating Ni coating prior to PVD deposition of carbon film, envisaging the application of these coating/substrate systems as bipolar plate in PEMFC. The results show that Ni + C coated magnesium alloy GW83 has the best corrosion resistance of 8.65 A cm(-2) and 0.80 mu A cm(-2) in the simulated cathodic and anodic environments. The release of metallic ions is also greatly inhibited by Ni + C coating. The interfacial contact resistance (ICR) of the magnesium alloy GW83 is decreased from 196.5 m Omega-cm(2) to 2.97 m Omega-cm(2) by Ni + C coating at the compaction force of 150 N-cm(-2). After potentiostatic tests, Ni + C coated sample has the lowest ICR of 15.6 m Omega-cm(-2) and 52.6 m Omega-cm(-2) in the anode and cathode environment, respectively. (C) Crown Copyright 2016, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.