An electromagnetic magnetoelectric transducer (EMAT) generates ultrasonic waves inside a metallic and/or ferromagnetic object through the interaction of high-frequency eddy currents, generated by a coil, with a magnetic field created by a permanent magnet or a pulsed electromagnet. Depending on the configuration of the eddy-current coil, either the Lorentz force or magnetostriction is used to introduce acoustic energy into the object. For nondestructive testing, both pulse-echo and through-transmission schemes can be implemented.
Purpose
The EMAT method is suitable for a wide range of nondestructive testing applications, such as measuring the wall thickness of boiler tubes and heat exchangers. It can be used for both manual and automated inspection of corrosion in pipelines and tanks. The EMAT method does not require a coupling medium to transmit sound, making it particularly well-suited for inspecting very hot or very cold components. The EMAT method allows for inspection through coatings and is not affected by contamination, oxidation, or surface roughness.
EMAT Instruments
An electromagnetic-acoustic transducer (EMAT) is an ultrasonic testing method in which ultrasonic waves are generated directly within the component being tested. It can be used to measure thickness without a coupling medium and to detect defects.
