Multifrequency Eddy Current Clad Thickness Measurement of Thin Aluminum Alloy Combinations Having Similar Conductivities

Clad materials can offer several performance advantages over unclad materials including better corrosion resistance, increased mechanical wear, improved joining qualities, and enhanced metallurgical properties. Clad materials are used extensively in automotive and building products, aerospace applications, and air conditioning equipment. Clad products pose special production problems due to their unique composition. These products might require clad on one or both sides and, depending on the product, the clad and core alloys come in several combinations. For proper process and quality control, products are required to be sampled to ensure that the clad layer is within a certain tolerance band for maximum and minimum thickness. The eddy current method described here can be employed to make a rapid, nondestructive determination of the clad thickness.