Sliding speed dependent tribological properties of hydrogenated diamond like carbon (h-DLC) film was studied in ambient atmospheric and inert conditions. At lower sliding speed, friction coefficient of h-DLC film is high while wear loss is insignificant. In this condition, tetrahedral (t) t-sp3 phase remains chemically stable as detected from Raman mapping of the wear tracks. In contrast, at higher sliding speeds, ultralow value of friction coefficient ~0.05 is measured despite of high wear loss. Here, chemical conversion of t-sp3 into amorphous (a) a-C/sp2 phase is observed. This phase migrates and enriches at the edge of wear track during sliding. Conversion of phase is driven by the thermal energy at higher sliding speeds and it results in surface oxidation. Migration of graphitized phase is supported by Acoustic Force Atomic Microscopy (AFAM) analysis of wear track. This phase migrates easily to the lower stress region due to its layered lattice structure and induces less friction coefficient. However, under the stress, wear loss of graphitized phase is high due to its softness and easy sliding along the c-axis. Friction coefficient was found to reduce further to 0.03 and 0.02 in Ar and N2 atmosphere as the passivation is sufficiently active through hydrogen atoms/molecules intrinsically present in the film.