Carbon composite coatings on Ti for corrosion protection as bipolar plates of proton exchange membrane fuel cells

Abstract

A highly corrosion resistant and conductive composite coating on Ti bipolar plates was prepared by the hydrothermal and impregnation method. The composite coating consisted of amorphous carbon immersed in suspension solution [polytetrafluoroethylene (PTFE) 10 wt.% + TiN nanoparticles 3 g/l]. The surface of coating was completely smooth and nano-holes on the surface of coatings were filled by PTFE and TiN particles. TiN particles were uniformly distributed in the coating when 0.1 mol/l of glucose was used as carbon source. The composite coating exhibited excellent conductivity and corrosion resistivity. It was revealed that corrosion current density, interfacial contact resistance, and contact angle were 0.009 μA/cm 2 , 13 mΩ cm 2 , and 115.53°, respectively. Meanwhile, it was shown that the corrosion current density of the coating was below 1 μA/cm 2 with a potentiostatic polarisation test (0.6 and -0.1 V). In summary, the Ti substrate with a carbon composite film immersed in suspension solution showed a great potential application in bipolar plates of proton exchange membrane fuel cells.