ECOSUS - Ecologically Sustainable Pretreatments for Painting Multimetal

Important results from the project

1. A developed/optimized thin film process/product that gives a corrosion protection as good as ZnPh. Systematic studies correlating process parameters film structure/composition - corrosion. Process/product development will be performed by chemical suppliers cooperating with the project team. 2. Predict the long term performance of the new coatings. 3. Introduce thin film technology at a paint shop/subcontractor treating one/few substrates. 4. Investigate Nickel-free ZnPh as an alternative pretreatment.

Expected long term effects

A deeper understanding of the relationship between process parameters, corrosion and coating composition has been achieved. For hot dip galvanized steel and hot rolled steel the corrosion performance are on the same level as for ZnPh but on cold rolled steel there is still a larger paint delamination. 6 week accelerated testing (ACT) showed higher impact than 3 years of field tests. Evaluation of methods for measuring the adhesion and for quality assurance. Ni-free ZnPh had similar results as ZnPh, but needs to be verified Contaminations on surface have a severe impact on corrosion.

Approach and implementation

The main objective was to Develop/optimize a thin film process/product that gives a corrosion protection as good as ZnPh by systematic studies correlating process parameters film structure/composition - corrosion protection. It has been cooperation with chemical suppliers. 3 panel applications have been performed. The two first had the focus on process variations, corrosion and coating composition. The third investigated how the cleanliness affects the corrosion and adhesion.