双层导电涂层厚度的涡流无损检测方法研究

Study on Eddy-current Nondestructive Testing Method of the Double-layers Conductive Coating Thickness

多涂层结构可显著提高基体材料的耐热性、耐磨性、耐腐蚀性等性能,因此在航空航天、船舶制造等行业得到广泛应用。在工程应用中,涂层厚度是否均匀对基体材料的物理性能产生重要影响。针对近几年出现的多层导电涂层材料,提出一种双层导电涂层厚度的电磁无损检测新方法。采用数值仿真和试验相结合的方法深入研究了多层导电涂层厚度检测中多层材料在厚度检测中的耦合问题及每层厚度与电导率对检测信号的影响问题。最后根据研究结论提出解耦算法反演各涂层厚度,并进行了试验验证。结果表明:文中提出的基于解耦算法的双涂层厚度检测方法对多导电涂层厚度的检测误差均低于10%。该方法也可进一步扩展到三涂层结构甚至四涂层结构的涂层厚度检测中。

The multiple-layered coating structure can significantly improve the heat resistance,wear resistance and corrosion resistance of the substrate material and therefore is applied widely in aerospace,petroleum and chemicals,and shipbuilding fields.The coating thickness plays key role in improving the substrate material performances.An eddy current nondestructive approach is presented to measure the coating thickness of the multiple-layered conductive coating structure.Above all,the interactions between the different layer thickness and the interaction of the coating thickness and coating conductivity on the detection signal are investigated by using numerical and experimental study.Thereafter,an approach to detect the coating thickness is proposed based on the decoupling algorithm,which is verified by the experiment.The experiment results indicate that the calibration values of coating thickness and those detected from the experiment agree well within the relative error of 10%.This approach can be extended further to the coating thickness measurement for the three-layered structure or four-layered structure.