Statistical Analysis of Influencing Factors on Eddy Current Measurement System

Abstract

The quality control of coating is regularly based on visual inspection and thickness measurement results using non destructive measurement system. In practice, coating quality control is performed after the coating is applied and during the exploitation life of the structural component. The coating quality is usually evaluated in accordance with the standard requirements, internal standards and technical specification. In this paper the thickness of electrically non-conductive coating on non-ferromagnetic, electrically conductive metal substrates measurements were demonstrated. Eddy current measurement method was applied to measure the coating thickness on aluminium substrate. The prepared samples consist of three different layer thicknesses. On each layer measurements were conducted under repeatability conditions (n=5). The measurements were performed by one person with two different measurement system at the same measurement condition. With the scope to determine the significance of the three selected effects (Coating thickness, Measurement system and Measurement spot) the ANOVA method were used. For the representative comparison of two measurement system the true value of each coating thickness was determined by means of image analysis software for metallographic specimens.