Wear test and Raman analysis of diamond-like carbon films prepared by bipolar-type plasma based ion implantation

Abstract

Diamond-like carbon (DLC) films are prepared on hard metal (WC-Co) substrates by a bipolar-type plasma based ion implantation. The mechanical properties and structural changes are examined by wear test and Raman spectroscopy as a function of negative pulse voltages (V_n) in the range of -5 to -15 kV. It is found that friction coefficient is around 0.2 for each sample. However, lower V_n causes better endurance (longer steady wear distance). Raman measurements reveal that the microstructure is changed to graphite-like structure after wear test. It is assumed that the degree of graphitization is larger as V_n increases.