SPE电解水用钛双极板表面氮化物涂层的制备与评价

Preparation and evaluation of nitride coating on the surface of titanium bipolar plate for SPE water electrolysis

采用PIRAC(粉末埋入反应辅助涂覆)氮化工艺在钛双极板表面制备一层氮化物防护涂层,研究了氮化温度对涂层的微观形貌、相组成,以及在模拟SPE电解水环境下耐蚀性、稳定性和导电性的影响。结果表明,涂层表面呈现颗粒状形貌,涂层内主要是TiN、Ti2N和α-Ti三相。氮化样品的耐蚀性得到明显提高,其中900℃氮化的样品在SPE电解水阳极高电位作用下的耐蚀性与基体相当。氮化后样品的界面接触电阻降低至3.5~4.2 mΩ/cm^2,在一定程度上会降低电解槽的欧姆损耗。在1.6~1.8 V电位范围内10 h的恒电位测试结果验证了氮化物涂层在高电位下的稳定性。

A protective nitride coating was prepared on the surface of titanium bipolar plate by PIRAC(powder immersion reaction assisted coating)process.The effect of nitriding temperature on the micromorphology and phase constitution of the coating,as well as its corrosion resistance,stability,and conductivity under simulated SPE(solid polymer electrolyte)water electrolysis environment was studied.The results showed that the surface of the coating had a granular morphology,and its interior was mainly composed of TiN,Ti2N,andα-Ti phases.The corrosion resistance of the nitrided sample was greatly improved.The sample nitrided at 900℃ had a corrosion resistance comparable to the substrate when it was used as an anode in SPE water electrolysis under high potentials.After nitriding,the interfacial contact resistance of the sample is reduced to 3.5-4.2 mΩ/cm^2,reducing the ohmic loss of the electrolytic cell to a certain extent.After 10 hours of potentiostatic polarization test,the stability of the nitride coating in the potential range from 1.6 V to 1.8 V was verified.