Effect of PVC/CPVC ratio of non-toxic, platy pigments on corrosion protection of acrylic-modified alkyd coatings

摘要

Purpose - This work aims to study the corrosion protection of laboratory-prepared micaceous zinc ferrite (MZF) pigment in anticorrosive paints for steel. Design/methodology/approach - Acrylic-modified alkyd coatings, based on MZF pigment, micaceous iron oxide (MIO) and zinc ferrite (ZF) pigments, were prepared at different pigment volume concentrations "PVCs" to the critical pigment volume concentrations "CPVCs" ratio, which denoted hereafter by A. Scanning electron microscope, weight loss measurements, water vapour transmission (WVT) and immersion in 3.5 per cent salt solution as well as physico-mechanical properties were performed to evaluate the paints anticorrosive performance. Findings - WVT and corrosion protection can be affected by the PVC/CPVC ratio for all systems. At any particular PVC, the barrier property of the pigment was the main factor affecting the WVT and corrosion protection. MZF pigment protected the carbon steel physically through barrier action and chemically by the reaction with the acidic acrylic-modified alkyd resin to produce soaps which passivate the substrate. Originality/value - Novel MZF paint could be used with optimum percentage in anticorrosive paints for steel protection especially in humid and coastal regions.