Selecting the correct electromagnetic inspection technology 

Department of Physics and Space Science, Royal Military College of Canada, Kingston, ON, K7K7B4, Canada

Adv. Mater. Lett., 2019, 10 (7), pp 441-448

DOI: 10.5185/amlett.2019.2262

Publication Date (Web): Jan 19, 2019

Copyright © IAAM-VBRI Press

E-mail: thomas.krause@rmc.ca  

Abstract

Eddy current (EC) technology for inspection of conducting materials is a potential solution when conditions preclude the application of other methods. Such conditions include presence of sound absorbing coatings, unavailability of a couplant, multiple conducting layers with air gaps, limited access or near surface cladding. However, the choice of a particular EC technology may not be clear due to sources of electromagnetic interference, choice of probe design, target configuration or even available equipment. In addition, the choice of EC based technologies is extensive, including conventional EC, low frequency EC, remote field EC and pulsed EC. Each of these technologies has its own challenges and limitations, which need to be considered prior to a commitment to system development. Probe choice becomes a function of the particular technique that has been selected and may include ferrite core sensing coils, GMRs or eddy current coil array. Finally, EC signal analysis methods need to be selected based on effects of potentially multiple varying parameters. This paper examines the potential of electromagnetic inspection technology, discussing its limitations, effects of common essential parameters and analysis methodologies. Examples of recent technology applications are given and the benefits and limitations of various technologies are compared and discussed.

Keywords

Eddy current testing, pulsed eddy current testing, low frequency eddy current testing, remote field eddy current testing, electromagnetic inspection, non-destructive evaluation.