ASTM D6547 Standard Test Method for Corrosiveness of Lubricating Fluid to Bimetallic Couple
8. Procedure
8.1 Remove the disks from the desiccator, being careful not to touch the finished surface.
8.2 Using the stirring rod, place two drops of the test fluid along a diameter in a line on the polished surface of each of three disks.
8.3 Remove the brass clips from the desiccator, being careful not to touch the area to be in contact with the steel disks.
8.4 Place the clips on the disks as indicated in Fig. 1 so that the center of the clip is in full contact with the wetted area of the disk.
8.5 Place the assemblies in a covered desiccating jar containing the saturated aqueous Ca(NO3)2·4H2O solution for ten days (relative humidity approximately 50 %).
8.6 Remove the assemblies from the desiccating jar after ten days. Absorb excess fluid from the assemblies with a lint-free cloth. Using a sharp pencil, mark an outline of the clips where they are in contact with the polished surface of the disks. Remove the clips and wipe the disks clean with a lint-free cloth.
8.7 Using the 10x power magnifier, examine the marked-off area for discoloration, etching, pitting, or other signs of corrosion. Fig. 2 depicts galvanic corrosion stains typical of tests using low-erucic rapeseed oil as the failing reference fluid.
