不锈钢双极板等离子喷涂TiC涂层耐腐蚀性研究

Study on Corrosion Resistance of Plasma-Sprayed TiC Coatings on Stainless Steel Bipolar Plates

为了提高质子交换膜燃料电池(PEMFC)双极板的耐腐蚀性,采用大气等离子喷涂技术(APS)制备TiC涂层,利用扫描电镜、X射线衍射仪表征涂层的形貌与组织,采用动电位极化、恒电位极化、电化学阻抗谱等方法研究了3种不同电流制备的TiC涂层在PEMFC环境中的耐腐蚀性能。结果表明:TiC涂层的腐蚀电流密度比不锈钢基体低了1个数量级,表明该涂层可以有效提高316L不锈钢的耐腐蚀性。随着喷涂电流的增大,500 A的涂层显示出了最佳的耐蚀性和导电性,这主要是由于随着电流的增大,粒子得到充分的熔化,使涂层致密度得到了提高,孔隙等缺陷减少。

To improve the corrosion resistance of proton exchange membrane fuel cell(PEMFC) bipolar plates, TiC coatings were prepared by atmospheric plasma spraying(APS). The morphology and structure of the coatings were characterized by scanning electron microscopy(SEM) and X-ray diffractometer(XRD). The corrosion resistance of TiC coatings prepared at three different currents in the PEMFC environment was studied by potentiodynamic polarization, potentiostatic polarization and electrochemical impedance spectroscopy(EIS). Results showed that the corrosion current density of the TiC coating was one order of magnitude lower than that of the stainless steel substrate, indicating that the coating could effectively improve the corrosion resistance of 316L stainless steel. With the increase of spraying current, the coating at 500 A was shown to have the best corrosion resistance and conductivity. This was mainly due to the increase in current, which fully melted the particles, increased the density of the coating, and reduced defects such as pores.