流动条件下铁基非晶纳米晶涂层钝化行为研究

Study on Passivation Behavior of Fe-based Amorphous Nanocrystalline Coatings under Flow Conditions

通过初期腐蚀电流密度监测、电化学阻抗谱、极化曲线和微观形貌分析,研究了静态和动态不同流速下铁基非晶纳米晶涂层的钝化与点蚀行为。结果表明:流动条件下,铁基非晶纳米晶涂层的自腐蚀倾向增加;随着流速的增加,钝化电流密度先增加后减小,流速为5 L/min时,钝化电流密度达到极大值3.09×10-4A/cm2;点蚀电位先降低后增加,滞后环面积先增加后减小,点蚀坑最大深度达50.61μm,可见高流速条件下涂层的点蚀能力降低。

Through monitoring the density of initial corrosion current,analyzing electrochemical impedance spectrum,polarization curve and micro-morphology,both corrosion tendency and pitting behavior of Febased amorphous nanocrystalline coatings at different flow rates were studied to show that,the self-corrosion tendency of Fe-based amorphous nanocrystal coatings increases under flow conditions.With the increase of the flow rate,the passivation current density increases first and then decreases and reaches 3.09x 10-A/cm²,a maximum value when the flow rate stays at 5 L/min.The pitting potential decreases first and then increases and the hysteresis ring area increases first and then decreases and the maximum depth of pitting pit reaches 50.61μm.This means that the pitting ability of the coating decreases at high flow rate.