Electromagnetic acoustic transducers

The electromagnetic acoustic transducers (EMAT) is a device for the excitation and detection of ultrasonic waves in conductive or magnetic materials. No physical contact is required with the test object because the coupling occurs through electromagnetic forces. The working distances are typically less than a milimeter and the probe often is alowed to rest on the surface of the test object. This ability to provide reproducible signals with no couplant is often more important than noncontact operation