A modified version of ASTM G85-A2 was developed in this work with the intention of targeting a relative humidity (RH) of 75% during the dwell period. The outcome was two different RH profiles, one that averaged 74% RH during the dwell period and another that averaged 61.5% RH during the dwell period. Both tests produced moderate exfoliation in AA2060-T3 after just 12 days of exposure. Other high-strength aluminum alloys (AA7075, AA2024) were exposed to the modified RH profiles, and both tests could correctly differentiate exfoliation resistance for these alloys. An average RH between 74% and 61.5% during the dwell period was found to produce consistent exfoliation ratings after a short exposure time. Electrochemical measurements made during salt spray testing were used to propose electrochemical mechanisms that occur during wetting and drying in atmospheric corrosion testing.

Subject
Films, Test methods, Time of wetness, Sensors, Materials, Sodium chloride, Exfoliation, Corrosion products, Kinetics, Salt spray corrosion testing, Aluminum alloys, Electrolytes, Samples
Keywords:
aluminum alloy, ASTM G85-A2, exfoliation corrosion, salt spray chamber design
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2020
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