Burnishing as an adhesion test?

A. Not common at all, but that doesn't mean it will not work. I would suspect it to be more akin for mid-hard to fully-hard platings. Perhaps those that are soft, like copper, zinc, tin, and the like, would tend to smear instead of flake or detach. Perhaps you could tell us more about your particular situation. G. Marrufo

A. Derek

Refer to ASTM B571 for coatings suitable for the burnishing test as well as the test method and applicability. The use of the test will depend on who is applying the coating and subsequent use of article coated.

A. One method is to rub a small area, about .2 x .2 inches with a smooth-ended rod for about twenty seconds. The pressure should be regulated as to place enough pressure such that the coating is visibly burnished but no digging. If the tool starts to dig, too much pressure has been applied or the rod/tool is not smooth enough. This test is only recommended for average or thin coatings, it won't work well for very thick coatings. After you do this you will want to inspect, probably under a microscope, 10X, and look for peeling, blisters and lifting. Any peeling, blisters or lifting indicates a failed test.