两种不锈钢在PEMFC环境下的耐蚀性

Corrosion resistances of two stainless steels in simulated PEMFC environment

用电化学方法测定了一种高Cr、Ni奥氏体不锈钢和316L在25℃和70℃时含2×10-6F-的H2SO4水溶液中的极化曲线,评价了氧化膜/碳纸和钝化膜/碳纸间的界面接触电阻。结果表明,在质子交换膜燃料电池(PEMFC)环境中,高Cr、Ni奥氏体不锈钢的耐腐蚀性优于316L,在两种介质温度下其钝化电流密度均低于10mA/cm2。钝化膜/碳纸的界面接触电阻明显比氧化膜/碳纸高,并随介质温度提高而增加。这种高Cr、Ni奥氏体不锈钢的氧化膜/碳纸和钝化膜/碳纸的界面接触电阻明显低于316L。

Polarization curves of a high Cr, Ni austenitic stainless steel and 316 L were measured in 0.05 mol/L H2SO4＋2 × 10^-6 F-at 25 ℃ and 70 ℃ by electrochemical method, and interfacial contact resistances before and after electrochemical corrosion were evaluated. The results indicate that the corrosion resistance of the high Cr, Ni austenitic stainless steel is better than that of 316 L in simulated PEMFC environment, and the passive current density is lower than 10 uA/cm^2. The interfacial contact resistance between the passive film and carbon paper is higher than that between air-formed oxide film and carbon paper, and increases with the increase of the temperature of medium. Both interfacial contact resistances of the high Cr, Ni austenitic stainless steel are lower than that of 316 L.