Influence of CrN-coating thickness on the corrosion resistance behavior of aluminium-based bipolar plates.

Abstract

The electrical and corrosion properties of CrN-coated aluminium alloy Magnal-45 (Al-5083) probes have been evaluated, in order to assess their viability to be used as bipolar plates in polymer electrolyte fuel cells. To this end, ceramic micro-layers of chromium nitride (CrN) with different thicknesses (3, 4. and 5 mu m) have been deposited on the surface of the Al alloy (Al-5083) using the physical vapour deposition (PVD) technique. A decrease in 2 orders of magnitude of I(corr) values for the coated Al has been observed compared to the as-received Al-alloy when the probes have been exposed to simulated anodic conditions in a micro-reactor. On the other hand, when subjected to a cathodic-simulated environment, the Al-CrN probes with 3 mu m and 4 mu m coatings have shown a decrease in I(corr) of one order of magnitude, while a variation of two orders of magnitude has also been obtained for the 5 mu m coating. (C) 2010 Elsevier B.V. All rights reserved.