Niobized AISI 304 stainless steel bipolar plate for proton exchange membrane fuel cell

► Niobized layer has been prepared on the surface of 304 SS by plasma surface diffusion alloying method. ► The niobized layer as protective layer of the 304 SS bipolar plate is evaluated. ► The niobized 304 SS has better hydrophobicity. ► The ICR and corrosion resistance of the niobized 304 SS are improved considerably.