Friction and wear maps of titanium alloy against a-C:H20% (DLC) film

Understanding the mechanism that control friction and wear is a complex and sometimes difficult task. There is a general recognition that these parameters are strongly dependent on load, sliding speed, temperature, time, contact geometry, surface roughness, ambient atmosphere and material surface compositions. Friction and wear maps may be a way to estimate friction and wear behavior over wide load and speed ranges. Additionally, they can be used as material selection guides, as well as design guides for different engineering applications.Despite the many attractive properties of DLC (diamond-like carbon) films, there are no maps available for DLC films. To date, on the web scientific search site there are only articles with dimensional wear maps for ceramic materials. This paper presents the wear rate map for DLC film with 20% hydrogen content (a-C:H20%) using a titanium alloy (Ti6Al4V) ball as counter body. Hardness, Raman scattering, and stress measurements were used to prove DLC film quality. Then, by using the results from the friction and wear tests it presents friction and ball wear volume maps as two new evaluations tools which better project the tribological relations between material behavior, load and speed. These maps successfully highlighted abrupt shifts in DLC material behavior, thus by-passing many hours of tests. Once more DLC maps are available, DLC films will become more economically viable for use in industry and space.