Construction and electrochemical corrosion behavior of carbon-based thin films on SS316L bipolar plates by magnetron sputtering

Abstract

The gradually increasing performance requirements of hydrogen fuel cells have posed a great challenge to the conductivity performance of bipolar plates (BPs). In this paper, the SS316L BP with a thickness of 100 μm is taken as the research object, a carbon-based thin film is plated on both surfaces by a magnetron sputtering ion plating system. The electrochemical corrosion behavior and microscopic characterization show that Cr-adopted carbon-based thin film is chemically bonded with the critical surface of the substrate, which can enhance the interfacial bonding force between the thin film and the substrate and form a more stable interfacial structure. The C element in the film structure inhibits the columnar structure of Cr atoms and their nitrides in the high-energy bonding layer, delays the pitting rate of corrosive media, and makes the initial corrosion current density of the surface-modified SS316L BP less than 10⁻⁵A/cm² (meet DoE(Department of Energy) 2025 requirement). This study clarifies the corrosion mechanism of stainless steel bipolar plate coatings under high-temperature and strong acidic conditions and provides a theoretical basis for the preparation of a novel type of highly corrosion-resistant multilayer carbon-based film.