Method for measuring non-uniform conductive material surface coating thickness according to eddy currents

Abstract

The invention discloses a method for measuring non-uniform conductive material surface coating thickness according to eddy currents. Based on the frequency sweep eddy current testing technology, continuous frequency within a certain range is used for stimulating one test point of a tested non-uniform conductive material provided with a coating and a substrate standard test block without the coating; the optimal measuring frequency at the test point is found, therefore, the effect of the nonuniformity of the conductivity of a substrate on the measurement of the surface coating thickness can be effectively avoided, and the accuracy of the measurement of the surface coating thickness is effectively improved.

Description

[0001] Technical field [0002] The invention relates to a non-destructive testing method, in particular to an eddy current thickness measuring method for the thickness of the covering layer on the surface of an uneven conductive material. Background technique [0003] In many important industrial applications, the covering layer on the surface of various engineering materials usually has dual functions of protection and decoration for the covered substrate. However, if the thickness of the covering layer is too thin, it will be difficult to play the above functions, and if it is too thick, it will cause economic waste, and the thickness of the covering layer is uneven or does not meet the specified requirements, which will have a negative impact on its multiple mechanical and physical properties. Therefore, in the process of coating construction and quality inspection, the thickness of the covering layer is an important control index. [0004] Depending on the material of ...

AI Technical Summary

Problems solved by technology

However, in actual production, due to problems in the smelting and casting process of engineering materials, there will always be some uneven crystal structures of materials, which will affect the uniformity of the conductivity of the matrix material. When the thickness of the covering layer is very thin, the difference in conductivity will affect the When the eddy current generated by induction is greatly affected, it is unfavorable for the measurement of the thickness of the covering layer. At this time, the error increases, and the thickness of the covering layer cannot be measured within the error range.

For example, carbon fiber composite materials have the characteristics of uneven electrical conductivity, and there is no effective detection method for the measurement of the surface covering layer.