Corrosion-resistant polymer coatings containing rare earth compounds

O KEEFE, W. G. FAHRENHOLTZ and J. O. STOFFER, Missouri University of Science and Technology, USAandE. L. MORRIS, PPG Aerospace, USA 

Abstract The incorporation of rare earth compounds as corrosion inhibitors in polymeric paint systems is presented. Specifically, uses of cerium salts in an electrolytically deposited coating commonly used in the automotive industry and praseodymium oxide in spray applied epoxy-polyamide primers for aerospace applications are discussed. Special emphasis is placed on the importance of phase of the rare earth material in relation to polymeric matrix as the effectiveness of the corrosion inhibition is strongly link to the starting materials, the formulated paint system and the ambient environment in which the coating operates in practice. 

Key words praseodymium, cerium, epoxy polyamide primer, eCoat, phase stability, corrosion protection mechanism. 

Substances Control Act (TSC A). In May 2006, the Occupational Safety and Health Administration (OSHA) implemented new, stricter regulations regarding workplace exposttre to chromates especially hexavalerrt chrome. Polymeric coating systems containing tare earth compound inhibitors that provided corrosion inhibition in a similar manner have been developed. Replacement of the chromate compotmds used in the primer coating with tare earth-based material removes 95 wt% of the hexavalent chromium contained in the coating system. 

2 Rare earth compounds as replacements of chromate compounds in polymer coatings 

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Corrosion-resistant polymer coatings containing rare earth compounds... 

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