XPS measurements of passive film formed on AISI 316L SS after electropolishing in a magnetic field (MEP)

Electrochemical polishing of metals and alloys is one of the most currently used finishing treatments, covering metallic biomaterials with complicated shapes (coronary stents, prostheses, etc.). A standard electropolishing (EP) process has been recently modified by including a magnetic field, and called the magnetoelectropolishing (MEP). Many surface properties and even mechanical features may be modified and improved by MEP. The changes are concerned with the surface film composition which undergo a modification. For the present studies, X-ray Photoelectron Spectroscopy (XPS) analysis was applied to measure the surface film composition on AISI 316L stainless steel. In conclusion both Cr-X/Fe-X compounds ratio as well as Cr/Fe total ratio of the 316L steel after EP and MEP were calculated and compared to reveal the advantage of the magnetic field used.