应用了楔型缝隙模型模拟了具有剥离涂层缺陷的X70管线钢在阴极极化条件下于新疆库尔勒土壤模拟溶液中的缝隙腐蚀。研究了极化时间(1~30h)、缝口控电位 (-850mV、-1000mV和-1150mV vs CSE)和缝口尺寸(0.15mm、0.30mm和0.45mm)等因素对缝内的极化电位、极化电流以及对应介质pH值的影响。实验结果表明，随着极化时间的延长，从缝口到缝底的极化电位梯度和极化电流梯度逐渐减小；随着缝口控电位的降低和缝口尺寸的增大，缝内试样的极化电位逐渐降低，而极化电流却逐渐增大，缝内试样对应介质的pH值也逐渐提高，进一步降低缝口控电位与增加缝口尺寸将使pH值的增加速度减小。
A wedge-shaped crevice cell used to model previously disbonded coating holiday of X70 pipeline steel under impressed current cathodic protection in simulated solution of desert soil of Ku’erle in Xinjiang. Distributions of polarization potentials and current along long direction of the wedge-shaped crevice were measured in different time intervals at different opening control potentials (-850mV, -1000mV and -1150mV vs CSE) and at different crevice opening thickness (0.15mm, 0.30mm and 0.45mm). The influences of applied control potentials and crevice thickness on polarization potentials, polarization current and pH value in crevice were investigated deeply. It was showed that gradients of polarization potential and current in crevice gradually decreased with times, due to the depletion of dissolved oxygen. It was found again that, a negative shift of opening control potentials, and increase of crevice opening thickness resulted in the decrease of polarization potentials, and the increase of polarization current in crevice. On the other hand, the pH value in crevice gradually increased also with more negative opening control potential, and with increase of the opening thickness. At the same control potential, the pH value from crevice opening to bottom increased first, then stabilized at a definite value. Moreover, more negative shift of the control potentials and bigger crevice opening thickness can make the stable pH value increase, but the increasing rate gradually decreased.
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