Surface modification of 316 stainless steel with platinum for the application of bipolar plates in high performance proton exchange membrane fuel cells

Abstract

316 stainless steel has been regarded as one of the promising candidates to replace graphite for bipolar plate application. However, the relatively high electrical resistance caused by the formation of passive oxide film and the insufficient corrosion resistance in long-term operation are two main concerns of 316 stainless steel bipolar plates. Low temperature active screen plasma alloying technology shows the ability to reduce electrical resistance and enhance corrosion resistance of 316 stainless steel bipolar plates to some extent, but still can not satisfy the Department of Energy (DOE) requirements. In this paper, active screen plasma co-alloying treatments with nitrogen and platinum are conducted to modify the surface of 316 stainless steel. The surface morphology, phase constitute, chemical composition and layer structure of treated 316 stainless steel are fully studied. A dense, columnar structured and single phase Pt3Fe deposition layer is produced on the surface of 316 stainless steel after treatments. Thanks to the excellent electrical conductivity and corrosion resistance of Pt3Fe, the surface electrical conductivity and corrosion resistance are greatly enhanced and satisfies the DOE requirements, contributing to the significant improvement of single cell performances.