Aluminium alloy corrosion detection by magnetic measurements

During corrosion, currents passing from anodes to cathodes generate magneti c fields. Fitting corrosion of aluminium alloys in aggressive media was det ected through magnetic field measurements, without electrical connection to the sample and without reference or auxiliary electrodes in the corrosion cell. A sodium chloride solution containing hydrogen peroxide or a solution of potassium hydroxide 2 mol l(-1) solution was used for corrosion tests. Two magnetometers developed by LETI were used: a superconducting quantum in terference device (SQUID) magnetometer and a nuclear magnetic resonance (NM R) magnetometer. The SQUID provided information on spatial distribution and direction of the currents. The NMR magnetometer was better for studying th e development of the corrosion over time. (C) 1998 Kluwer Academic Publishe rs.