Tribological Properties And Structural Evolution Of Fullerene-like Carbon Films

Friction is a common phenomenon in human daily life from ancient times to the present,and it has great scientific and engineering significance in mechanical movement.With the rapid development of science and technology,the material loss and energy waste caused by friction have gradually become the key factors to limit the efficiency of mechanical movement and the life of mechanical parts.Among the many anti-friction materials,diamond-like carbon based thin films have attracted a great deal of attention all over the world because of their excellent tribological and mechanical properties.In particular,during the study of diamond-like carbon(DLC)films,the researchers have discovered a unique structure of carbon film materials embedded in amorphous carbon networks which is the fullerene-like microstructure.Fullerenelike nanostructure is a kind of microstructure composed of crimped and cross-linked graphite plane,which gives the film excellent elastic recovery properties and appropriate hardness.Therefore,the carbon film containing fullerene-like microstructure is an ideal candidate for lubrication.In this paper,the relationship between film hardness and elasticity and fullerene-like clusters was investigated by changing the energy supply mode.The evolution of the structure of fullerene-like thin films with deposition time and the variation of tribological properties with deposition time were investigated,and the change rule of the tribology performance of the fullerene-like carbon film with the load is explored.The results are as follows:By changing the form of energy supply(DC and pulse)and hydrogen concentration,the relationship between hardness and elasticity and fullerene-like clusters was studied.Draw the following conclusions:(1)Majority of H atoms is distributed in a-C,and a small amount is distributed in Fullerene-like.(2)High H growth environment reduces the degree of curvature and crosslink of graphitic basal planes,and inhibits their growth.(3)The dc form easily leads to the formation of large graphitic layer stacks,and conversely the pulse form tends to induce the degree of curvature and crosslink of graphitic layers each with shorter sizes.The differences may be a result for the energy minimization process of the film growing system in a very short pulse period at low temperature.By changing the film deposition time,the evolution of the structure of the fullerene-like carbon film and the change of the tribological properties with the time of the deposition were investigated.The results show that the content of the fullerene structure in the carbon film is kept unchanged after the deposition time is increased.The friction coefficient of Fullerene-like carbon films deposited for 3 hours is changed from low friction to super-slippery with increasing load,and the spherical or outer graphite-like particles are formed which are beneficial to reduce the friction of carbon films.The friction coefficient of Fullerene-like carbon films is changed from low friction to super-slippery with increasing load.The friction experiments of self-paired Fullerene-like carbon film show that with the increase of load,the wear mark area decreases and the thickness of friction film increases,resulting in a more perfect graphitization structure,which obviously reduces the real contact area and decreases the friction coefficient.