Corrosion and Electrochemical Properties of CrMoSiN Coatings for Bipolar Plates in Polymer Electrolyte Membrane Fuel Cells

CrMoSiN films with varying Mo and Si contents were deposited on SS316L stainless steel by Physical Vapor Deposition (PVD) to evaluate their corrosion and electrochemical properties as bipolar plates for Polymer Electrolyte Membrane Fuel Cells (PEMFCs). The sputtering current of Mo and Si targets was adjusted to obtain different compositions in the CrMoSiN coatings, enabling a systematic study of the influence of these elements on the performance of the coatings. Scanning Electron Microscopy (SEM) revealed that the CrMoSiN coatings have a dense and uniform microstructure, which is essential for improving their mechanical and corrosion-resistant properties. X-ray Diffraction (XRD) analysis confirmed that the coatings exhibit a preferred orientation along the (200) direction, indicating good crystalline structure and stability. The effects of Mo and Si incorporation on the corrosion properties of CrMoSiN coatings were thoroughly investigated in simulated PEMFC environments, which mimic the harsh conditions within fuel cells. Potentiodynamic polarization tests and Electrochemical Impedance Spectroscopy (EIS) results demonstrated that the incorporation of Mo and Si significantly enhances the corrosion resistance of the coatings, making them more durable and effective in these environments. The findings suggest that CrMoSiN coatings, particularly those with optimized Mo and Si content, have promising potential as protective materials for bipolar plates in PEMFCs, significantly improving their efficiency and longevity under operational conditions. The corrosion mechanism of the CrMoSiN coatings was also investigated and discussed in detail.