Evaluation of tribological properties of DLC films used in sheet forming of aluminum sheet

Diamond-like carbon (DLC) films, i.e. hard carbon films having amorphous structure, are known to have excellent tribological properties against various materials. However, because of its low adhesion strength to a substrate and/or the difficulty of preparing the required thick film, thin films have not been as extensively applied to tools as expected. In this paper, the basic tribological properties of DLC films against aluminum alloys are reported. More specifically, films with different compositions prepared by various techniques and coated onto the forming tools were subjected to tribology tests using aluminum alloys as the counter face material. We constructed a heavy-load friction tester that enables the application of load similar to that in actual metal forming of the material. It was found that among various hydrogenated DLC films with or without inclusion of a silicon element, non-silicon containing films show the best tribological properties.