Advanced Techniques – Scanning
Eddy current data can be collected using automated scanning systems to improve the quality of the measurements and to construct images of scanned areas. The most common type of scanning…
Thickness Measurements of Non Conducting Coatings on Conductive Materials
The thickness of nonmetallic coatings on metal substrates can be determined simply from the effect of liftoff on impedance. This method has widespread use for measuring thickness of paint and plastic coatings. The coating…
Thickness Measurements of Thin Material
Eddy current techniques can be used to perform a number of dimensional measurements. The ability to make rapid measurements without the need for couplant or, in some cases even surface contact, makes…
Verification of Heat Treatment
With some materials, such as solution heat treatable aluminum alloys, conductivity measurements are often made verifying that parts and materials have received the proper heat treatment. High purity aluminum is soft and ductile, and…
Conductivity Measurements
One of the uses of eddy current instruments is for the measurement of electrical conductivity. The value of the electrical conductivity of a metal depends on several factors, such as…
Tube Inspection
Eddy current inspection is often used to detect corrosion, erosion, cracking and other changes in tubing. Heat exchangers and steam generators, which are used in power plants, have thousands of…
Surface Crack Detection Using Sliding Probes
Many commercial aircraft applications involve the use of multiple fasteners to connect the multi-layer skins. Because of the fatigue stress that is caused by the typical application of any commercial…
Signal Filtering
Signal filtering is often used in eddy current testing to eliminate unwanted frequencies from the receiver signal. While the correct filter settings can significantly improve the visibility of a defect…
Reference Standards
In eddy current testing, the use of reference standards in setting up the equipment is particularly important since signals are affected by many different variables and slight changes in equipment…
Impedance Matching
Eddy current testing requires us to determine the components of the impedance of the detecting coil or the potential difference across it. Most applications require the determination only of changes…
