Traditionally the remote field eddy current (RFEC) phenomenon has been applied to the inspection of ferromagnetic tubes in heat exchangers, boilers etc. The RFEC probe has an exciter and sensor coil spaced such that most of the magnetic field received by the sensor is due to the field that has diffused through the pipe wall. The phase difference between the exciter and sensor signals is indicative of the defect dimensions. This same idea has been applied to the design of a new RFEC probe for inspecting flat ferromagnetic structures [1–3] and thick aluminum plates [4].
展开▼
