The corrosion inhibitive properties of various kinds of potassium zinc phosphate pigments: Solution phase and coating phase studies

It was found that the mole ratio of KOH/ZnCl2 could significantly affect the corrosion inhibition properties of the PZP. Increasing the KOH/ZnCl2 mole ratio up to 2.5 caused significant improvement of the corrosion inhibition properties of the PZP both in the solution and coating phases. It was shown that PZP 2.5 could release Zn and P ions more than PZP 3.5 indicating its higher solubility in the 3.5 wt.% NaCl solution. PZP could significantly retard both anodic and cathodic reactions rates through releasing high amounts of Zn and P ions. PZP 2.5 enhanced the corrosion protection properties of the epoxy coating more than PZP 3.5 and decreased the adhesion loss significantly.