ELECTROCHEMICAL EVALUATION METHOD OF LOCAL SUSCEPTIBILITY TO CORROSION OF METALLIC MATERIAL SURFACE AND ITS DEVICE

摘要

PURPOSE:To measure local corrosiveness and the locations of corrosive points rapidly and accurately while a metallic material remains as it is in a non-destructive shape, by measuring polarization curves simultaneously and independently at a plurality of positions on a surface of the metallic material. CONSTITUTION:Polarization curves are measured simultaneously and independently at a plurality of locations on a surface of a metallic material 16, such as, stainless steel, etc. with welding portions. An electrode for measuring corrosion is used which a large number of probe electrodes 14 are surrounded by means of a guard electrode 15 and both electrodes 14, 15 are mounted to the same end surface. For example, the electrode for measurement is employed which the probe electrodes 14 in platinum with 1mm diameters are arranged at intervals of 1mm and the circumference is enclosed by means of the guard electrode 15 in platinum. A mixed water solution of sulphuric acid and potassium thicocyanic acid is made use of as an electrolyte 7, polarization curves are measured simultaneously and independently about each probe electrode 14 by means of a potentio-stud 8 while employing a stainless steel plate with welding portions as a body to be tested 16, and the curves are recorded by means of a recorder 21.