Corrosion resistance of a magnetic stainless steel ion-plated with titanium nitride

This in vitro study evaluated the corrosion resistance of a titanium nitrid e (TiN) ion-plated magnetic stainless steel (447J1) for the purpose of appl ying a magnetic attachment system to implant-supported prostheses made of t itanium. The surface hardness of the TiN ion-plated 447J1 alloy with varyin g TiN thickness was determined prior to the corrosion testing, and 2 mu m t hickness was confirmed to be appropriate. Ions released from the 447J1 allo y, TiN ion-plated 447J1 alloy, and titanium into a 2% lactic acid aqueous s olution and 0.1 mol/L phosphate buffered saline (PBS) were determined by me ans of an inductively coupled plasma atomic emission spectroscopy (ICP-AES) . Long-term corrosion behaviour was evaluated using a multisweep cyclic vol tammetry. The ICP-ABS results revealed that the 447J1 alloy released ferric ions into both media, and that the amount of released ions increased when the alloy was coupled with titanium. Although both titanium and the TiN-pla ted 447J1 alloy released titanium ions into lactic acid solution, ferric an d chromium ions were not released from the alloy specimen for all condition s. Cyclic voltamograms indicated that the longterm corrosion resistance of the 447J1 alloy was considerably improved by ion-plating with TiN.