聚苯胺/钼酸涂层的电化学合成及其耐蚀性能

Preparation of Polyaniline/Molybdate Coating and Evaluation of Its Corrosion Resistance

为了提高Q235碳钢的防腐蚀性能,先对其进行钝化处理,然后分别在不含和含有钼酸的苯胺和草酸混合溶液中,采用循环伏安法在碳钢电极表面电化学合成聚苯胺(PANI)和聚苯胺/钼酸(PANI-MoO2-4)涂层;利用开路电位-时间曲线、动电位极化曲线及电化学阻抗谱分析了PANI涂层和PANI-MoO2-4涂层在3.5%NaCl溶液中的防腐蚀性能。结果表明:PANI-MoO2-4涂层对Q235碳钢的腐蚀防护作用明显优于PANI涂层;与碳钢相比,PANI-MoO2-4涂层的自腐蚀电位升高了近188 mV,自腐蚀电流密度约为碳钢的1/5,低频阻抗模值|Z|0.05 Hz约为碳钢的53倍。

Q235 mild steel electrode was initially passivated and then immersed in the solutions of aniline and oxalic acid with or without molybdate to allow the formation of polyaniline(PANI) coating and PANI-MoO_4^(2-) coating via cyclic voltammetric route.The anticorrosion behavior of as- prepared PANI coating and PANI-MoO_4^(2-) coating in 3.5%NaCl solution was evaluated based on measurements of open circuit potential-time curves,potentiodynamic polarization curves and electrochemical impedance spectra.Results indicated that PANI- MoO_4^(2-)coating was much superior to PANI coating in terms of the corrosion protection for Q235 mild steel.Namely,as compared with that of the mild steel substrate,the corrosion potential of PANI-MoO_4^(2-) coating was increased by about 188 mV,and its corrosion current density was about 1/5 of that of the mild steel substrate,while the low frequency impedance value was about 53 times as much as that of the mild steel substrate.