ASTM D6547 Corrosiveness of Lubricating Fluids to a Bimetallic Couple
Two different metals in contact with each other may undergo an electrochemical reaction causing corrosion of one of the metals. This reaction is accelerated in the presence of a humid atmosphere. The presence of a lubricant film may inhibit this galvanic corrosion process. This test determines the ability of a fluid to slow or prevent the corrosion of a brass/steel bimetallic couple in the presence of a 50% relative humidity atmosphere.
A steel disk is polished and coated with the test oil. An acid etched brass clip is attached and the assembly is placed in a 50% Relative Humidity chamber. After 10 days the bimetallic couple is removed, separated and examined for corrosion, pitting or other signs of reaction. Reported is a pass if no corrosion, pitting or discoloration is observed, or a fail with an explanation.