钛合金过渡层对燃料电池不锈钢双极板表面改性薄膜综合性能的影响

Enhancement of Corrosion Resistance with Ti35 Alloy LayerInserted between Cr_(0.23)C_(0.77) Coatings and Stainless Steel Plate of Fuel Cell

针对在燃料电池不锈钢双极板电堆上应用的Cr0. 23C0. 77非晶改性薄膜使用寿命低的问题,仍然采用脉冲偏压电弧离子镀技术,在Cr0. 23C0. 77薄膜与316L不锈钢基体之间增加制备一层耐点蚀钛合金过渡层,考察过渡层对改性薄膜表面综合性能的影响。首先在316L不锈钢基体上选择TA1、TA9、TA10和Ti35四种工业钛合金分别进行预选过渡层材料的沉积制备,对所得样品进行耐蚀性能的对比检测,结果显示,在模拟电池阴极环境下,四种样品中Ti35材料的耐蚀性能最优,可确定为过渡层的首选材料;之后再在不锈钢双极板样品上制备有Ti35过渡层的316L/Ti35/Cr0. 23C0. 77复合薄膜,与只有Cr0. 23C0. 77单层薄膜的样品一起进行表面综合性能的对比测试,结果表明,添加Ti35钛合金过渡层后,双极板在保持原有导电性能的接触电阻为3. 0 mΩ·cm2(0. 6 MPa下)左右和水接触角大于100°的疏水性能的基础上,耐蚀性能得到了明显的改善,在模拟阴极环境的动电位腐蚀测量条件下,腐蚀曲线中出现了一个明显的平台钝化区,从-0. 3～0. 9 V较宽的电位范围内腐蚀电流一直保持低于10-6A·cm-2水平,并且破钝电位高达1. 0 V以上。这将有利于提高双极板的表面防护性能和使用寿命。

We addressed the pinhole corrosion problem at the interface of the surface modified, amorphous Cr0.23 C0.77 coating and 316L stainless-steel plate of fuel cell. The solution was an inserted Ti-alloy layer,deposited by pulse bias arc ion plating. The influence of the Ti-alloy insertion layer on the interfacial corrosion was investigated in operation environment of proton exchange membrane fuel cell （PEMFC）. The preliminary results show that the Ti35 alloy transition layer has a major impact. For example, the Ti35-alloy layer significantly increased the corrosion resistance （and bipolar plate service time） under the conditions：at an interface contact resistance of ～ 3.0 mΩ· cm2 and a water-contact angle above 100°. Simulated in PEMFC environment, a well-defined passive region platform showed up in the potentiodynamic polarization curve; the current density was always below 10-6 A · cm-2 （0.6 MPa） in -0. 3 to 0. 9 V range; and the breakdown potential was up to 1.0 V.