Tribological Behavior of Ion Implanted AISI 440C Stainless Steel under Oil Lubricated Condition

Abstract

The tribological behaviors of nitrogen and titanium ion implanted AISI 440C stainless steel were studied by using an oscillating ball-on-disk tribometer under oil lubricated condition. The results showed that the ion implantations would significantly decrease the friction coefficient of the samples. To interpret the effect mechanism of the ion implantation on tribological performance, the surface morphology and oil wettability of the ion implanted samples were investigated by using a three-dimensional white interferometer and a contact angle analyzer, respectively. In addition, the surface structures and components of the samples were analyzed by using XRD and XPS techniques. The results indicated that the low friction coefficients of the ion implanted samples can be attributed to the new phases formed on the sample surfaces. For nitrogen ion implanted sample, the metal nitrides, supersaturated interstitial N and some C-O-N compounds appear on the sample surface. For titanium ion implanted sample, apart from TiO2and TiC phases form at the AISI 440C steel surface. Those components increase the surface energy of the AISI 440C steel and are in favor of the formation of the thin oil film.