METHOD FOR MEASURING CORROSION CHARACTERISTIC OF INSIDE OF PROTECTIVE COATING PEELING AND APPARATUS THEREFOR AND PROTECTION MONITORING ELECTRODE

摘要

PROBLEM TO BE SOLVED: To make it possible to measure the electric resistance of the underground embedment environment of the spacing in the protective coating overlap parts of protective coating steel products and the corrosion rate of the steel in the spacing from ground in addition to the convention protection potential measurement. SOLUTION: The protection monitoring electrode 6 consisting of a cylindrical member simulating the spacing 17 of the protective coating overlap parts and an electrode chamber is disposed near the underground protective coating steel products 1. A first electrode 61, a second electrode 62 and a reference electrode 63 are previously disposed within the protection monitoring electrode 6 and an AC impedance measuring instrument 20 is connected to between the first electrode 61 and the second electrode 62. The electric resistance of the spacing 17 and the corrosion rate of the steel in the spacing are measured and the protective potential of the spacing with a switch 7A as an open circuit is measured by using the first electrode 61 and the reference electrode 63.