Open AccessProtection of alodine coatings from thermal aging by removable polymer coatings.
Author(s) -
Brett R. Wagstaff,
Robert W. Bradshaw,
LeRoy L. Whinnery
Publication year - 2006
Language(s) - English
Resource type - Reports
DOI - 10.2172/897634
Subject(s) - chromate conversion coating , materials science , corrosion , conversion coating , coating , polymer , composite material , aluminium , metallurgy
Removable polymer coatings were evaluated as a means to suppress dehydration of Alodine chromate conversion coatings during thermal aging and thereby retain the corrosion protection afforded by Alodine. Two types of polymer coatings were applied to Alodine-treated panels of aluminum alloys 7075-T73 and 6061-T6 that were subsequently aged for 15 to 50 hours at temperatures between 135 F to 200 F. The corrosion resistance of the thermally aged panels was evaluated, after stripping the polymer coatings, by exposure to a standard salt-fog corrosion test and the extent of pitting of the polymer-coated and untreated panels compared. Removable polymer coatings mitigated the loss of corrosion resistance due to thermal aging experienced by the untreated alloys. An epoxide coating was more effective than a fluorosilicone coating as a dehydration barrier