An automated method for corrosion testing of coating systems on magnesium alloys

Abstract The present work introduces an automated corrosion test for coating systems on magnesium alloys, which is based on the titration method introduced by General Motors [1], in which the dissolution rate of magnesium is determined from the amount of HCl added to a sodium chloride solution required to maintain a constant pH value. It is demonstrated that this technique allows a screening of various types of coatings on magnesium alloys yielding much more information than a standard salt spray test or a simple standard immersion test. The main advantage lies in the continuous measurement of the corrosion rate without disturbing the corrosion system and without the need for cleaning the specimens from corrosion products in order to measure weight changes.