High temperature nitrogen implantation of Ti-6Al-4V II: Tribological properties

Abstract

A high temperature ion implantation method employing a high current density beam ( e.g. 500 μA cm -2) of nitrogen ions, was used to modify the near-surface microstructure of Ti-6Al-4V to improve its tribological performance. A systematic study was performed with nitrogen implantations at temperatures from 400 to over 1000 °C, and doses in the range (0.1−1.0) × 10 18 N + 2− N + cm −2. Tribological properties ( e.g. coefficients of friction) were evaluated in ambient air as a function of applied load, under both unlubricated and perfluoroether fluid lubricated conditions. Metallographic examinations were performed to characterize wear damage. The lowest unlubricated coefficient of friction and greatest wear resistance were observed for the 1000 °C implantation treatment. These tribological properties were correlated with the distribution of the implanted nitrogen and resultant microstructure (as described in Part I of this paper series).