METHOD FOR DETECTING FAULTS OF A DIELECTRIC COATING ON THE SURFACE OF AN ELECTRICALLY CONDUCTING SUBSTRATE

摘要

PCT No. PCT/CH82/00109 Sec. 371 Date Jun. 15, 1983 Sec. 102(e) Date Jun. 15, 1983 PCT Filed Oct. 11, 1982 PCT Pub. No. WO82/01514 PCT Pub. Date Apr. 28, 1983.The method consists in placing a conductive underlayer (1) coated by a dielectric layer (5) in a conductive medium in which an excitation electrode (2) is positioned at a distance from this underlayer (1). This underlayer (1) and this excitation electrode (2) are being connected to the corresponding terminals of an alternative-current generator (4) and between this electrode (2) and this underlayer (1) one interposes a catcher coil (6) oriented in a plan perpendicular to the electric field lines and a potential-measuring electrode (7) in the opening of said coil (6) and one determines the impedance resulting from the voltages and currents detected.