AN ASSESSMENT OF FLUOROTITANATE CONVERSION COATINGS FOR PREPAINTED APPLICATIONS

摘要

Chromate conversion coatings (CCC) have been successfully used for decades in coil industry to improve corrosion resistance of metal coated steels and provide adhesion to paints. Off late due to health and environmental concerns there is common drive in the industry to replace CCC. A number of different Ti-Zr based conversion coatings, often including a polymeric constituent, are commercially available as a more environmentally friendly alternative to the chromate based treatments. These Ti-Zr conversion coatings may be applied by dipping, spraying or roll on processes. The general characteristics of these coatings are known to be quite good and similar to that formed by CCC. However, the performance of painted substrates subjected to Ti-Zr based pre-treatments may be affected by the composition of the conversion bath. This paper makes an assessment of the performance of different fluorotitanate conversion coatings especially with regard to pre-painted applications.