Cheap, lightweight, and malleable Al-alloy 5052 is suggested as alternative materials of graphite bipolar plates (BPPs) in proton exchange membrane fuel cells (PEMFCs). This work presents the first research in producing Au/Ni-P multilayer coatings on Al-alloy BPPs using an electroless Ni-P along with immersion gold techniques. The modified Al-alloy BPPs are investigated to evaluate the coating structure, corrosion resistance, interfacial contact resistance, electrochemical impedance of single cells, and single cell performance. The results indicate that the Al-alloy BPPs with Au/Ni-P coatings, in which Ni-P is prepared at pH 4.5, reveal the lowest contact resistance and the best corrosion resistance (I-corr = 8.43 x 10(-6) A cm(-2)) in a 0.5 M H2SO4 + 2 ppm HF solution among all of the modified specimens. The electrochemical impedance of the Au/Ni-P coating after long-term operation is 9.1 m Omega. In addition, the power density of the single cells assembled with the Au/Ni-P/Al-alloy BPPs is 0.84W cm(-2) measured at a cell voltage of 0.7 V. comparable to that with graphite BPPs (0.80 W cm(-2)), in the test conditions of this study. We find that the Au/Ni-P multilayer coating is very appropriate for modifying Al-ally BPPs in PEMFC systems. (C) 2012 Elsevier B.V. All rights reserved.