Zinc-rich epoxy coatings are widely used to protect steel against corrosion, due to their excellent corrosion resistance. However, these coatings usually use a large amount of Zn powder and organic solvents, which not only wastes resources, but also produce a high level of volatile organic compounds (VOC).
In a new study, three different flake metal powders (Zn, ZnAl alloy and ZnAlMg alloy) were used to replace the spherical Zn powder, to develop environmentally friendly coatings with low pigment content. The coatings were evaluated by salt spray test and electrochemical tests, and the results showed that the use of flake metal powders instead of spherical zinc pigments can enhance the electrical connection between metal particles, prolong the path of corrosive medium infiltration into the coatings, enhance the physical shielding effect of the coatings, and reduce the pigment content by one third. Among them, the ZnAl coatings displayed the best anti-corrosion performance, resisting salt fog corrosion for 28 days.
This study was published in Progress in Organic Coatings, Volume 175, February 2023.
