The assessment of anticorrosive behavior of calcium carbonate from different sources in alkyd-based paints

Great progress has been devoted recently in corrosion protection of metals via using cheap and efficient protective organic coatings. Calcium carbonate is common filler used in coatings industry due to its distinctive properties and the variation of its sources. The scope of this work is to study the effect of calcium carbonate developed from different sources (e.g. natural calcite, marble and egg shell wastes) on the corrosion protection performance of anticorrosive coatings. The different calcium carbonate sources were characterized using different analytical techniques, such as X-ray diffraction (XRD), X-ray fluorescence, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The three calcium carbonates were then incorporated in solvent-based paint formulations using medium oil-modified soya-bean dehydrated castor oil alkyd resin. The physico-mechanical properties of dry films were tested. Immersion test, electrochemical impedance spectroscopy and SEM/EDAX were used to inspect the corrosion protection performance of coatings containing the three sources of calcium carbonate. The results showed that the corrosion efficiency of egg shell was the best among the three sources due to its unique particle shape structure.