Tribology and wettability of Na-ion implanted glassy carbon

A study has been made of friction, wear and wettability of ion implanted glass like carbon. Substrates used were glassy carbon (GC). Na-ions of 150 keV were implanted in GC with doses ranging from 1/spl times/10/sup 15/ to 1/spl times/10/sup 17/ ions/cm/sup 2/ at room temperature. Tribological tests were carried out using a ball (SUJ-2 or alumina) on disk (GC) equipment. Contact angles of water were measured by means of a sessile drop method. It is found that friction coefficients during wear tests were around 0.2 and unstable for the non-implanted specimen, and stable for implanted specimens. The lowest friction coefficient was 0.05, observed for the system of an alumina ball on the higher dose specimen. Wear resistance was improved with the dose over 1/spl times/10/sup 16/ ions/cm/sup 2/. The contact angle of water was about 87 degrees at the dose up to 5/spl times/10/sup 16/ ions/cm/sup 2/, and it decreased to 43 degrees at the dose of 1/spl times/10/sup 17/ ions/cm/sup 2/. It is considered that the improvement of wear resistance is caused by the generation of diamond like carbon structure by radiation effect and the reduction of the contact angle is influenced by implanted Na. It is concluded that Na-ion implantation in GC results in high wear resistance and different wettability.