高阻介质中阴极保护防止剥离涂层管道缝隙腐蚀机理的研究

For cathodic protection current is difficult to reach the deep crevice gap of disbonded coating pipeline which in high-resistivity environment,and high insulated coating has shielding effect, pipeline has serious crevice corrosion and perforation result from the cathodic protection effect reduced greatly. Therefore, searching protective mechanism and control method of cathodic protection in high-resistivity environment to avoid crevice corrosion is very necessary. In this project, the change rule and distribution relationship of the chemical and electrochemical parameter in coating dissection of the gap are studied by simulating configurations and scanning Kelvin probe,and a unsteady-state mathematical model which can forecast the change law of corrosion parameters in crevice gap in disbonded coating pipeline crevice is derived; Through analyzing the test and the simulation results, space-time evolution figure of protection mechanism of high-resistivity environment in a cathodically protected crevice is obtained .Moreover, this project puts forward the mechanism of compound action and control method of cathodic protection to prevent crevice corrosion in high-resistivity environment.In addition,the examples prove the feasibility and rationality of protection.This research is prominent in scientific understanding the protective mechanism and control theory of the cathodic protection for crevice corrosion in high-resistivity environment, and which provides experiment and theory basis for cathodic-protection practice of pipeline.

高阻介质中剥离涂层管道的缝隙深处阴极保护电流难以到达以及高绝缘涂层的屏蔽作用，阴极保护效果大大降低，致使管道发生严重的缝隙腐蚀而穿孔。因此，寻求高阻介质中阴极保护防止缝隙腐蚀机理及其控制方法的研究非常必要。本项目通过设计人工模拟缝隙构型，采用扫描Kelvin探针等微区电化学测量方法，研究了涂层剥离缝隙内化学和电化学参数的变化规律和分布关系；建立了阴极保护下剥离涂层管道缝隙内腐蚀环境的暂态过程数学模型，该模型可以预测阴极保护下剥离涂层缝隙内腐蚀参数的变化规律；综合分析了试验和模拟结果，获得了高阻介质中阴极保护下缝隙内保护机理的时空演化图，提出高阻介质中阴极保护防止缝隙腐蚀的作用机理及控制方法，并通过实例验证该保护机理的合理性和保护方法的可行性。本课题的研究，旨在突出对高阻介质中阴极保护防止剥离涂层管道缝隙腐蚀保护机理及控制理论的科学认识，为管道阴极保护工程实践提供了实验和理论依据。

高阻介质中剥离涂层管道的缝隙深处阴极保护电流难以到达以及高绝缘涂层的屏蔽作用，阴极保护效果大大降低，致使管道发生严重的缝隙腐蚀而穿孔。因此，寻求高阻介质中阴极保护防止缝隙腐蚀机理及其控制方法的研究非常必要。.本项目通过设计人工模拟缝隙构型，采用微电极测量等微区电化学测量方法，开展阴极保护下剥离涂层管线缝隙腐蚀行为及其机理的研究，获得了以下结论和研究成果：.（1）获得了涂层剥离缝隙内化学和电化学参数的变化规律和分布关系；.（2）建立了阴极保护下剥离涂层管道缝隙内腐蚀环境的暂态过程数学模型，该模型可以预测阴极保护下剥离涂层缝隙内腐蚀参数的变化规律，与实际结果十分吻合；.（3）综合分析试验和模拟结果，获得高阻介质中阴极保护下缝隙内保护机理的分布图;.（4）提出高阻介质中阴极保护防止缝隙腐蚀的作用机理及控制方法。.（5）研究结果与预期研究计划书保持一致,发表论文3篇，其中2篇EI、1篇SCI（由于时间关系SCI文章还在审稿之中,1篇会议论文EI检索中）。