With funding from the US Naval Research Agency, the Naval Air Systems Command pretreated aluminum alloys with chromates and tested the corrosion resistance of the treated aluminum alloys. In the experiment, 7075-T6 aluminum alloy sheet was selected and placed in a salt spray environment at 35 ° C and a sodium chloride content of 5%. The internal current was monitored in real time by a regulator, and the degree of corrosion was characterized by optical instruments.
The study found that in the salt spray environment, the internal current and the area of the corroded area of the aluminum alloy after pretreatment were smaller than that of the aluminum alloy plate without chromate pretreatment, but the corrosion depth increased by 3 times. This means that although the chromate pretreatment improves the corrosion resistance of aluminum alloys to a certain extent, it faces the problems of thickness loss and stress concentration, and it is difficult to ensure the structural integrity. In the future, researchers will continue to improve and perfect the chromate pretreatment and corrosion protection technology.