A study of effect of micaceous iron oxide on corrosion protection behavior of waterborne zinc-rich silicate coatings

During the recent half century، using of inorganic zinc-rich coatings has been one of the efficient methods to prevent corrosion of steel structures in corrosive atmospheres. Micaceous iron oxide (MIO) is one of the most widely used pigments for anticorrosive barrier coatings. In the present study waterborne zinc-rich silicate coatings were formulated based on nanosilica-modified potassium silicate and different contents of zinc and micaceous iron oxide (MIO). After being applied on steel panels، the coatings were subjected to atomic force microscopy (AFM)، electrochemical impedance spectroscopy (EIS)، corrosion potential measurements and salt spray test. Replacement of zinc by MIO in the formulation of zinc-rich paints was revealed to shorten the duration of cathodic protection stage while on the other hand gave satisfactory results in salt spray test. It was concluded that MIO pigments can be used to control the reactivity of zinc-rich silicate coatings.