Inhibitory properties of calcium exchanged silica epoxy paintings

Epoxy paints with different contents of calcium-exchanged silica were formu lated maintaining the ratio PVC/CPVC constant. Steel painted samples were s ubmitted to immersion tests monitored by open circuit potential and electro chemical impedance. The behaviour of calcium-exchanged silica was compared with chromate and red iron oxide. The electrochemical measurements were com plemented by water vapour permeability, Auger electron spectroscopy and the rmally stimulated currents. The results suggested a film forming mechanism for calcium exchanged silica paintings. In total immersion conditions, they had better performance than the iron oxide, closely approaching the chroma te. (C) 2001 Elsevier Science Ltd. All rights reserved.