An extensive field study was made of the corrosion of aluminum alloy panels in over fifteen years of service in three regions of the USA. Panels removed from service exposed vehicles were subjected to further testing to determine the relationship between field service, accelerated laboratory corrosion testing, and marine environment exposure for two years at Daytona Beach, Florida.
In addition, two 42 year old aluminum bodied Dyna Panhard vehicles were recovered in France, examined closely, and subjected to similar tests.
Few examples of significant corrosion were found in the field, and only one example of filiform corrosion on aluminum sheet in service. Steel panels on the same vehicles frequently rusted through, and filiform corrosion was seen occasionally. Laboratory tested aluminum panel samples frequently showed filiform corrosion and severe intergranular corrosion. No filiform corrosion on recovered panels has been observed to date at the Daytona Beach site, although some laboratory prepared samples exhibit general corrosion. Performance of aluminum alloy panels is clearly superior to steel.
Many laboratory corrosion tests in current use are far too severe, and do not predict actual service behavior. The relevance of accelerated testing to service behavior is discussed.