Investigation of selected surface properties of AISI 316L SS after magnetoelectropolishing

The aim of the paper is to present the surface film composition formed on AISI 316L SS and its surface microhardeness after electropolishing (EP) and magnetoelectropolishing (MEP) in a wide range of the process conditions. The electropolishing EP process has been performed under natural convection (in still electrolyte), and under a forced convection (moderate stirring below 0.1 m/s), both on the polarization plateaux and much above it. Another series of experiments was carried out on AISI 316L SS samples prepared by MEP at 350 mT. The samples prepared by mechanical abrasive polishing, with the grit size up to 1000, served as a reference. First of all, concerning the surface film composition, a big difference in iron contents was observed between the samples after mechanical polishing and electropolishing. On the other hand, there were much less differentiations of chromium contents in surface film formed on 316L SS samples after each of the studied electropolishing conditions, and even mechanical polishing. The total Cr:Fe ratio was also studied, with quite promising results obtained. At the end the conclusions concerning the selection of proper electropolishing conditions have been formulated.