Wear Life of Fullerene-like Hydrogenated Carbon Films under Different Loads

The wear life of carbon-based films is depending on the loading that the life decrease with increase load.However,the inner nanostructure is an another key to influence the wear life.The hydrogenated fullerene-like carbon (FLC:H) films are a new family that with high elastic recovery and low friction coefficient,much better than that of carbonbased films reported before.Therefore,to determine the wear life varation with loads is much important.In present work,FL-C:H films was grown on the surface of the silicon wafer by DC plasma enhanced chemical vapor deposition.The structure of the films was confirmed by scanning electron microscopy(SEM),high resolution transmission electron microscopy (HRTEM) and Raman spectroscopy.The hardness of the wear trace surface of the film at the wear stage was measured by nano-indenter.The friction coefficient and the life span of the film under different loads were studied by using the ball disc reciprocating friction and wear tester.The relationship between the changing of the film life under different loads,as well as the film hardness of the wear trace surface was discussed.By measuring the surface hardness of the wear traces of the films with different proceeding time of friction under load of 10,20 and 25 N,it can be speculated that during the friction,plastic deformation occurs in the surface of the wear trace surface during the running-in period and the hardness of the contacting surface of the films increases.When the friction coefficient is stable,the surface hardness remains stable within a certain range.When the load becomes larger,the initial surface hardness of the wear trace also increases accordingly.Following the Archcard's law,we can obtain that TW=(Db/k) H.The product of the wear time (wear life) T of hydrogenated fullerene-like carbon films and the load W to the product of the total thickness D and the wear width b to the wear coefficient k ratio is proportional to the hardness of films.The conclusion can be proved that it is reliable from the point of experiments.It can be explained that with the load increases,the film friction coefficient decreased and its wear life remained stable phenomenon,that is,the load increases,the film surface hardness also increases,so the wear and tear weakened,making the wear life and stability.