1990 Volume 76 Issue 9 Pages 1496-1503
Under-film corrosion behavior of Zn-Fe alloy coating in the tip of corrosion was investigated using the atmospheric exposure test. The better correlation between chlorine penetration distance and paint exfoliation width from scribe was recognized. The formation of deteriorating coating layer due to chlorine ions attacking of coating is an important factor controlling the paint adhesion of zinc alloy coated steel sheets.
The durability of coating against chlorine penetration was affected by the coating weight and total zinc weight in the coating. Zn-Fe (10 20% ) alloy coating had better durability against chlorine ion attacking than pure Zn coating because of the difference of coating itself corrosion behavior between these coatings. The effect of Zinc phosphate film was not mainly the controlling factor of durability against chlorine penetration.
