Corrosion and cathodic disbondment resistance of epoxy coating on zinc phosphate conversion coating containing Ni2+ and Co2+

In this study, surface morphology, composition and anti-corrosion properties of zinc phosphate conversion coating with nickel and cobalt additives were investigated. In the second step, the phosphated coating was used as the pretreatment for the epoxy coating. The results showed that the corrosion resistance of phosphated coating containing additives has been increased significantly. The phosphated coating containing mixture of additives formed on the surface, has lower porosity and higher compaction than other samples. Also by adding a mixture of additives to the composition of the phosphated coating, adhesion strength and resistance to the cathodic disbondment of organic coatings were increased.