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Investigations of the corrosion of aircraft metals have been in progress continuously at the Bureau since ~925. Approximately 25,ooo specimens of aluminum alloys, magnesium alloys, anti stainless steels (6o alloys in all) have been corroded by means of accelerated laboratory tests or by exposure to the weather or to sea water. The exposure localities were Washington, D. C., Hampton Roads, Va., and Coco Solo, Canal Zone. Corrosion was determined by means of loss in tensile properties, or was measured directly on cross-sections examined with the microscope at high magnification.
Corrosion in aluminum alloys occured as either the "pitting" or intercrystalline types. As shown in RPI316 by Willard Mutchler in the July Journal of Research, intercrystalline corrosion was responsible for serious embrittlement in duralumin-type alloys. Methods of heat treatment were evolved that eliminate intercrystalline attack. The work indicated that pitting could be minimized by preparing alloys from high purity components, and by keeping the copper and iron contents low. Binary magnesium-aluminum alloys were found to become more susceptible to corrosion as the aluminum content increased. Small additions of zinc or tin rendered these alloys more resistant to attack. Stainless steels of the ~8 chromium--8 nickel type containing small additions of molybdenum were more corrosion-resistant than similar alloys without addition elements, or those with small additions of titanium or columbium.
Suitable surface coatings were developed, for both aluminum and magnesium alloys, to markedly improve their resistance to corrosion under severe saline conditions. The effect on corrosion produced by joining by means of rivets or by gas-welds, seam-welds, and spot-welds was determined. Important data were also obtained on the potential effects
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## Abstract A joint project of different european aircraft manufacturers involves the investigation of the involvement of microorganisms in corrosion damage in aircraft. In a first step, the microflora of corrosion failures was investigated. Swab samples were taken from corroded sites and were cul
Condensed moisture from ingressed humid air was responsible for inducing corrosion within the aft radar antenna from an RAAF P-3C Orion maritime surveillance aircraft. Porosity in the silver-plating of a flexible brass waveguide allowed moisture to penetrate to the brass substrate and cause dezincif