Hybrid processing of Ti-6AI-4V using plasma immersion ion implantation combined with plasma nitriding

Abstract

Based on the fact that the Ti-6A1-4V alloy has good mechanical properties, excellent resistance to corrosion and also excellent biocompatibility, however with low wear resistance, this work aims to test plasma processes or combination of plasma and ion implantation processes to improve these characteristics. Two types of processing were used: two steps PIII (Plasma Immersion Ion Implantation) combined with PN (Plasma Nitriding) and single step PIII treatment. According to Auger Electron Spectroscopy (AES) results, the best solution was obtained by PM for 150 minutes resulting in ∼ 65 nm of nitrogen implanted layer, while the sample treated with PIII (75 minutes) and PN (75 minutes) reached ∼ 35 nm implanted layer. The improvement of surface properties could also be confirmed by the nanoindentation technique, with values of hardness increasing for both processes. AFM (Atomic Force Microscopy) characterization showed that the single step PIII process presented greater efficiency than the duplex process (PIII + PN), probably due to the sputtering occurring during the second step (PN) removing partially the implanted layer of first step (PIII).

Keywords