The Study Of Comprehensive Performance And Application Performance In PEMFC Bipolar Plates Of CrNiN Coating With Different Ni Content

In order to research the comprehensive performance of Cr Ni N coating and its application performance in proton exchange membrane fuel cell,Cr Ni N coating with different Ni contents were prepared on the surface of 304 stainless steel by using the closed field magnetron unbalance sputtering ion plating.the morphology and structure of the coating were analyzed by SEM、XPS and XRD,the comprehensive performance of the coating was researched by test of frictional wear,electrochemistry and surface energy.At last,the electrochemical performance,conductivity and hydrophobicity of Cr Ni N coating in proton exchange membrane fuel cell were studied.The results showed that the Cr Ni N coating combined with matrix well,the structure of the coating was compact,the surface of coating was integrated without flaking cracks and other defects.The Cr N coating is mainly composed of Cr N and Cr₂N phase and the Cr Ni N coating is mainly composed of Cr N phase and Ni elemental substance.The coating would change from crystal to amorphous with Ni doping.When the Ni content was 13.16at.%,the coating grain size reached the minimum at 10.7 mm with the highest microhardness and elastic modulus,which was16.13 GPa and 259 GPa,respectively.The wear-resisting property of coating can be significantly improved by Ni doping,the wear rate reached the lowest when Ni content was 13.16 at.%,however,The wear-resisting property of coating turned worse while Ni content increased unceasingly.And the corrosion rate of Cr N coating layer in3.5%Na Cl solution would be reduced by Ni doping.The test of simulated conditions of proton exchange membrane fuel cell electrochemical environment showed that the corrosion resistance of 304 stainless steel could be significantly improved by coating modification.The Cr N coating possessed the best corrosion resistance,the coating corrosion resistance performance which would turn worse with Ni doping.The test of contact resistance between coating and carbon paper showed that the Cr N coating possessed the optimal conductive performance which would be reduced by Ni doping.The 304 stainless steel surface hydrophobic properties was greatly increased after coating modification.Ni doping helps to improve the hydrophobic performance of Cr N coating and Cr Ni N coating has more advantageous to water management of the proton exchange membrane fuel cell.