TRIBOLOGICAL STUDY OF TI6AL4V COATED WITH AMORPHOUS CARBON FILMS OBTAINED BY ELECTRODEPOSITION

Amorphous carbon films can be used to increase the wear resistance of titanium alloys, aiming for a coating with lubricant properties on metal surface, reducing its coefficient of friction (COF) thus increasing the wear resistance. Carbon films obtained by electrochemical deposition techniques have attracted a lot of interest, in view of their potential in relation to the vapor phase deposition techniques, in particular as regards the dispensing of vacuum system, room temperature operation and the technological transfer. At high electric fields, the organic molecules polarize and react on the electrode surface, forming amorphous carbon films. The aim of this work was to obtain carbon films on Ti6Al4V substrate using as electrolyte N;N-dimethylformamide. Two surface finishes of the substrate were tested: mechanical and electrochemical polishing, to compare the type of surface preparation to obtain these carbon films. The film morphology was characterized by atomic force microscopy (AFM). The wear resistance was evaluated by dry wear in a ball-on-plate type tribometer and the profile of wear tracks was analyzed by profilometry analysis and scanning electron microscopy (SEM). Results show that these carbon films can improve, significantly, the wear resistance of titanium alloys.