Is there are a correlation between B117 salt spray testing and electrochemical testing?
A1. I am not aware of any long term, detailed comparisons in the literature, but I have done a few dozen parallel tests of up to three weeks (500hrs) on painted and plated parts. The good parts were always good and the bad parts were always bad. Potentiodynamic polarization did measure differences in the materials that were not detectable by visual inspection of the parts exposed to salt spray, and these defects in the coatings were usually apparent within three days by electrochemical measurement. Salt spray testing is simply – pass or fail. If the part fails there is no way to determine why, and if the part passes there is no indication that is it actually better than any other passing part.
