The Main Factors Affecting Measurement Accuracy of Eddy Current Coating Thickness Gauge
1. When the thickness of the cover layer is greater than 25 μm, the error is roughly proportional to the thickness of the cover layer.
2. The conductivity of the base metal has an influence on the measurement, which is related to the composition of the base metal and the heat treatment method.
3. Any kind of thickness gage requires the base metal to have a critical thickness. Only greater than this thickness, the measurement will not be affected by the thickness of the base metal.
4. The eddy current thickness gauge has an edge effect on the measurement of the sample, that is, the measurement near the edge or inner corner of the sample is unreliable.
5. The curvature of the sample has an effect on the measurement, and this effect increases significantly as the radius of curvature decreases.
6. The surface roughness of the base metal and the covering layer affects the measurement accuracy, and the roughness increases, and the impact increases.
7. The eddy current thickness gauge is sensitive to the adhesive substances that hinder the close contact between the probe and the surface of the coating. Therefore, the dirt and covering layer on the probe surface should be removed before measurement, and the probe should be in constant pressure vertical contact with the test surface during measurement.
