Use of the spotface technique to reduce assessing time of the painted galvanized steel corrosion

摘要

The increasing interest of the steel industry on materials with higher corrosion resistance has led to a continuous development of corrosion process evaluation techniques. One major goal of the new methods is to reduce the analysis time. A common technique consists of scribing the painted galvanized steel surface in order to expose the steel to the corrosive environment, but still demands usually long times for measurement. In this work, a new analysis technique for assessing the corrosion propagation time is used with the major benefit of reducing the time of analysis, without altering the basic corrosion mechanisms. In this method, industrially-painted galvanized steel sheets have the painting and coating removed from a 13-mm diameter spot in order to increase significantly the cathodic/anodic area ratio. This increase leads to a lower sacrificial layer protection power, thus reducing significantly the total time of the corrosion test as compared to the time consumed during the usual scribe method test.