Comparative XPS analysis of passive layers composition formed on AISI 304 L SS after standard and high-current density electropolishing

In the paper, there are described chemical compositions of passive surface layers formed on AISI 304L (EN 1.4307) stainless steel after standard (EP50; i=50 A/dm(2)) and high-current density (EP1000; i=1000A/dm(2)) electropolishing. For the studies, a mixture of orthophosphoric and sulfuric acid electrolyte in proportion 1:4 was used. The survey and high-resolution spectra of Cr 2p, Fe 2p, S 2p, P 2p, Ni 2p and C 1s are presented. On the basis of the obtained results it was noted that the chromium-to-iron ratio (Cr/Fe) after EP50 was about 3.5 times higher than that after EP1000 treatment. The phosphorus-to-sulfur ratios after EP50 and EP1000 electropolishing were 0.13 and 0.3, respectively, and nickel to the sum of chromium and iron coefficient (Ni/Cr+Fe) for both electrochemical polishing was equal to 0.04. Copyright (c) 2014 John Wiley & Sons, Ltd.