Cr/TiN/Ti nanocrystalline composite fihns of about 3 μm were deposited on titanium bipolar plates for proton exchange membrane fuel cell （PEMFC） by hollow cathode deposition （HCD） ion plating. The electrical contact resistance of Ti plate with and without the nanocrystalline films was tested respectively, and their electrochemical corrosion performance was evaluated in 0.05 mol/L H2SO4＋2 mg/L NaF solutions bubbled with H2 or O2 at 60℃ by means of po larization measurements. The results show that the contact resistance of the coated Ti plate was obviously lower than that of bare Ti plate, with about 12 mQ.cm2 under a compressive presure 1000 N/cm2. The passivation current density of the coated Ti plate was one order of magnitude smaller than that of the bare Ti plate under the condition of charging hydrogen, suggesting that the corrosion resistance of titanium bipolar plate is greatly improved by the deposition of Cr/TiN/Ti nanocrystalline composite films.
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