Corrosion-resistant nanostructured carbon-based coatings for applications in fuel cells based on bipolar plates

The paper reports on carbon coatings deposited by accelerated C-60 ion beam irradiation onto the VT1-0 titanium alloy surface at different substrate temperatures, considering potential applications in fuel-cell bipolar plates. We identified the temperature range for forming a conductive carbon nanocomposite coating (CNC) at different accelerating voltages (U-a). The obtained CNC consists of graphite nanocrystals embedded in an amorphous diamond-like matrix. The nanocomposite containing similar to 40% of sp(3) bonds is formed at T-s = 300-400 degrees C under U-a = 6 kV. The increase in accelerating voltage to 8 kV reduces the temperature of the nanocomposite formation to T-s = 200 degrees C. Interface contact resistance (ICR) of a CNC coated titanium plate decreases to 2.6 +/- 0.7 mOhm & sdot;cm(2) at a sealing pressure of 1.5 MPa, which is close to carbon paper - graphite contact resistance. This low ICR value persists after prolonged corrosion tests. Tribological studies established high wear resistance and high adhesion of CNC to titanium substrate, showing potential for stable operation of coated bipolar plates in mobile applications. CNC allows to overcome the limitation of corrosion-caused ICR increase, which makes CNC-coated titanium a promising candidate to substitute gold-coated stainless steel as a raw material for bipolar plates of proton-exchange membrane fuel cells.

Automated summary

The paper presents a study on carbon coatings deposited by accelerated C-60 ion beam irradiation onto a titanium alloy surface, focusing on their potential application in fuel-cell bipolar plates. The study identifies the temperature range and accelerating voltage required for forming a conductive carbon nanocomposite coating. The obtained coating shows promising characteristics, including low interface contact resistance, high wear resistance, and high adhesion to the titanium substrate.