Formulation of Anti-Corrosion Coatings Using a mill scale-Based Pigment

This study investigates the use of industrial mill scale waste as a sustainable source for developing an effective anti-corrosion pigment. Mill scale, a mixture of iron oxides (FeO, Fe₂​O₃​, and Fe₃​O₄​), forms as a crust on steel parts when heated above 575°C. Its formation is an unavoidable byproduct of steelmaking, hot or semi-hot forging, and hot rolling processes. To create the anti-corrosion pigment, we combined mill scale with a specific ore. We then incorporated this synthesized pigment into various protective coating formulations, systematically varying the proportions of mill scale at 100%, 42.85% and 28.57%. Prior to application on steel substrates, the substrates were polished to ensure optimal adhesion of the paint. The prepared coating formulations were characterized for their dry extract, flow time, and density. Electrochemical evaluation of the coated samples was performed using an AUTOLAB potentiostat-galvanostat controlled by ANOVA software. A standard three-electrode setup was employed for all experiments, consisting of a saturated calomel reference electrode, a platinum counter electrode, and the coated sample as the working electrode. The electrochemical analysis was conducted under specific operating conditions: a scan range of Ei​=0±250 mV/E.C.S, a scan speed of 1 mV/sec, and a 3.5% NaCl electrolyte. The results of the electrochemical analysis revealed significant anti-corrosion performance from the coatings. Notably, formulations containing the pigment with 28.57% mill scale demonstrated enhanced corrosion resistance. This research highlights a promising and sustainable approach to anti-corrosion solutions by effectively repurposing industrial byproducts.