Corrosion resistance of NiCr(Ti) coatings for metallic bipolar plates

Abstract

In the present work, the electrochemical behavior of various NiCr(Ti) protective coatings manufactured using laser cladding were studied. The coatings were obtained by adding Ti in different wt% to the NiCr-based feedstock material. Thus, the coatings are investigated as new materials with potential applications for metallic bipolar plates used in polymer electrolyte membrane fuel cell (PEMFC) applications. The electrochemical tests were carried out at room temperature in a solution of H2SO4 0.5 M (pH = 0.3) + 2 ppm F- used as electrolyte. Chronoamperometry measurements were first employed in simulated anodic and cathodic conditions for 6 h. Afterward, electrochemical impedance spectroscopy (EIS) studies were performed in the frequency range of 100 mHz − 100 kHz with an alternative voltage amplitude of 10 mV. The recorded EIS data were fitted with an equivalent electrical circuit (EEC). Furthermore, the potentiodynamic polarization curves were recorded at a scan rate of 1 mV/s in the potential range of −250 mV to + 250 mV versus to the OCP values. Finally, the obtained data were analysed and compared. The studies showed that the corrosion behavior of the studied materials increase with the content of Ti addition.