Influence of new thin lyer pretreatments on anti-corrosive properties of automotive coatings

 
For decades the zinc phosphate process worked as the global standard for excellent corrosion protection in combination with electrocoat (EC) in the automotive industry. Due to more stringent environmental regulations the zinc phosphate process must be replaced by alternative products. In a research project new thin layer pretreatments on various automotive substrate materials are compared with zinc phosphate in its corrosion protection properties in combination with EC. The mutual influence of substrate, pretreatment and EC is investigated and possible failure mechanisms are related to the layer properties. Results from new VDA cyclic corrosion test, intensified outdoor weathering, electro-chemical and other methods will be presented and offer insights into the performance of these systems and will help to identify strengths and weaknesses of specific combinations of the new technologies. An outlook will be given about the benefit of this study for manufacturers of steel, organic coatings, pretreatment chemistry, and automotive industry.