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Chromate replacement in coatings for corrosion protection of aerospace aluminium alloys

journal contribution
posted on 01.09.2011, 00:00 authored by T Markley, J Mardel, A Hughes, Bruce HintonBruce Hinton, A Glenn, Maria ForsythMaria Forsyth
Mixed rare earth organophosphates have been investigated as potential corrosion inhibitors for AA2024-T3 with the aim of replacing chromate-based technologies. Cerium diphenyl phosphate (Ce(dpp) 3) and mischmetal diphenyl phosphate (Mm(dpp) 3) were added to epoxy coatings applied to AA2024-T3 panels and they were effective in reducing the amount and rate of filiform corrosion in high humidity conditions. Ce(dpp) 3 was the most effective and characterisation of the coating formulations showed approximately a factor of 5 reduction in both the number of corrosion filaments initiated as well as the length of these. Mm(dpp) 3 appeared to reduce the corrosion growth rate by a factor of 2 although it was the more effective inhibitor in solution studies. Spectroscopic characterisation of the coatings indicated that the cerium based inhibitor may disrupt network formation in the epoxy thus resulting in a coating that absorbed more water and allowed greater solubilisation of the corrosion inhibiting compound.

History

Journal

Materials and corrosion

Volume

62

Issue

9

Pagination

836 - 840

Publisher

Wiley - VCH Verlag GmbH & Co. KGaA

Location

Berlin, Germany

ISSN

0947-5117

eISSN

1521-4176

Language

eng

Publication classification

C1.1 Refereed article in a scholarly journal

Copyright notice

2011, WILEY-VCH Verlag GmbH & Co. KGaA