摘要
采用等离子喷涂技术在304不锈钢表面沉积Ti N涂层,研究其在燃料电池环境中的腐蚀和导电性能。采用XRD和SEM对涂层组织结构和微观形貌进行了表征,通过动电位极化曲线、电化学阻抗谱技术比较了涂层与基体在模拟电池环境中(0.3 mol/L H_2SO_4+2 mg/L HF)的耐蚀性,并测定了接触电阻。结果表明:涂层的自腐蚀电位显著高于基体的,且腐蚀电流密度下降近1个数量级,这与所制备厚约20μm涂层的均匀致密性有关。在360 h浸泡过程中,涂层的开路电位显著高于基体,稳定性良好,虽阻抗随时间有所降低,但仍维持较高值,涂层能够对基体提供有效保护。在138 N·cm-2压力下,Ti N涂层的接触电阻为50 mΩ·cm-2,低于基体的,表现出更优越的导电性能。
TiN coating was prepared on the surface of 304 stainless steel by plasma spraying technology. The microstructure and phase composition of the coating was characterized by X-ray diffraction （XRD） and scanning electron microscopy （SEM）. The corrosion performance of the 304 stainless steel without and with TiN coating was assessed by the potentiodynamic polarization and electrochemical impedance in the simulated proton exchange membrane fuel cell solutions containing 0.3 mol/L H2SO4 plus 2 mg/L HF. Moreover, electrical conductivity of them was also compared. The results indicated that TiN coating significantly increased the free corrosion potential of the steel and induced a decrease of the corresponding corrosion current density by one order of magnitude, which is attributed to the presence of the continuous and compact coating of about 20 μm in thickness. During the whole period of 360 h immersion, the open circuit potential of the coating was obviously higher than that of the bare substrate, suggesting the excellent stability of coating. The impedance of the coating decreased slightly with immersion time but still remained in high level, suggesting that the TiN coating could provide the effective protection for the substrate. The interface contact resistance of the TiN coating was about 50 mΩ·cm^-2 by an applied load of 138 N·cm^-2, obviously smaller than that of the bare 304 stainless steel, exhibiting better conductivity.
出处
《中国腐蚀与防护学报》
CAS
CSCD
北大核心
2017年第1期63-68,共6页
Journal of Chinese Society For Corrosion and Protection
基金
国家自然科学基金项目(51101023和51301181)
江苏省产学研项目(BY2016029-07)
常州市科技项目(CF20140004)
天津市应用基础与前沿技术研究计划重点项目(15JCZDJC39700)~~
关键词
304不锈钢双极板
等离子喷涂
TIN涂层
耐蚀性
304 stainless steel bipolar plate, plasma spraying, TiN coating, corrosion resistance
