Novel eddy current field modulation of magneto-optic garnet films for real-time imaging of fatigue cracks and hidden corrosion

A new magneto-optic/eddy current imaging technology promises to revolutionize the nondestructive inspection of aging aircraft and also to provide new ways to inspect unlikely materials such as non-metallic composites. As the name implies, the technology is a hybrid of magneto-optic imaging techniques and novel eddy current excitation methods. The result, a device we call a magneto-optic/eddy current imager, or MOI, allows one to inspect such things as aircraft lap joints for both cracks and hidden corrosion in approximately one tenth the time it would take with conventional eddy current inspection equipment. The device produces realistic, real-time images of both cracks and corrosion and has proven to be a reliable in-service tool. The MOI has been approved for the inspection of Boeing, Douglas, and Lockheed commercial aircraft. It is also currently being used by the U.S. Air Force, NASA, and many other organizations.