Micro-stamping offers high productivity, and accuracy at low-cost. Thus, it is considered as a prominent method for fabricating bipolar plates (BPP) with micro-channel arrays on large metallic surfaces that to be used in Proton Exchange Membrane Fuel Cells (PEMFC). Tribological variations, surface conditions (e.g. roughness, hardness, and coating) and surface interactions between micro-stamping dies and blank metal plates play a critical role in determining the surface quality, channel formation and dimensional precision of bipolar plates. This study aimed to understand the effect of die surface topography on the manufactured BPP surfaces and correlate, if exists, bipolar plate surface quality (surface topography) to bipolar plate performance (corrosion resistance). A total number of 2000 micro-stampings were performed with 51µm-thick uncoated SS 316L and 1µm-thick ZrN coated SS316L sheet blanks. Optical and scanning electron microscopy examinations were conducted to observe topographic variations. In addition, corrosion resistance tests were carried out at certain intervals. Analysis of variance (ANOVA) technique was used to determine the significance of the process parameters on roughness and corrosion resistance values. The results revealed similar roughness trends for die and plate surfaces. ZrN coating found to be improving the corrosion resistance behavior of plates substantially.
Keywords: Microforming, Tribology, PEM fuel cell, Bipolar plate.