| The thermal stability of graphite amorphous carbon films limit its application range.In this paper,a new method have been proposed by doping the strong carbide forming elements and strong oxide forming elements to the working layer of amorphous carbon films.Prepared amorphous carbon films doped with double hysteresis carbon oxidation type element on the basis of keeping its good mechanics and tribological properties,the binding rate of O and C in the friction contact surface is delayed by the different action mechanism of the doped phase.Increase the limit service temperature of films.However,due to the limitation of coating equipment,the lack of target position cause the commonly used Cr target have no place to install.In this paper,different metal Me-C(Cr,Mo,Ti,Al)gradient composite layers were prepared by magnetron sputtering technique.Compare of the binding strength between film and substrate to determine the superior binding layer material.Expanded the selection range of the bonding layer materials of amorphous carbon films.And the Me-C complete films was prepared.By contrast the mechanical properties and thermal oxidation ability to selecting the better,non-Cr doped amorphous carbon films(Mo-C,Ti-C).Based on its technological parameters,the different doping levels of Mo-Al-C and Ti-Si-C films were prepared by the double thermal oxidation mechanism.And the properties and structure were characterized.The results show that the thickness of Cr-C,Mo-C,Al-C and Ti-C films were 398 nm,423 nm,385 nm,370 nm.The bond strength of Cr-C,Mo-C and Ti-C films binding layers was evaluated as HF2.Al-C binding layer is HF3.The bond strength of Cr-C,Mo-C and Ti-C films evaluated to well.The as-deposited Cr-C?Mo-C?Ti-C amorphous carbon films were graphite like carbon film.This film has more sp2 hybrid carbon bond.The volume percentage of the doped metal phase were 11 vol%?10.4 vol%?12.0 vol%.The thickness of working layer are 851 nm,889 nm,899 nm.The combined strength grade is HF2.Under the 2 N load and GCr15 steel ball on the grinding,the friction coefficients were 0.201,0.0243,0.179.Under the 10 N load were 0.167,0.159,0.352.has a good anti friction properties.The specific wear rate of Cr-C,Mo-C and Ti-C films under different loads were on the range of 0.56?1.85×10-16 m3/(N·m).Compare with Cr-C films,Mo-C and Ti-C films have good mechanical and tribological properties.When the Cr-C amorphous carbon film annealing at 400?,the film surface appears dense damage point.Thin film structure collapse.Its mechanical properties deteriorat.The Mo-C film with less carbon loss during annealing at 400?.Film structure is complete,and the film base bonding strength is good.The friction coefficient is small and stable.The Ti-C films annealed at 400 C loss more carbon.The film oxidized to failure.The limit thermal service temperature of Cr-C and Ti-C films is 350?.The limit thermal service temperature of Mo-C films is 350?On the basis of Mo-C and Ti-C films,the Mo-Al-C and Ti-Si-C amorphous carbon films were prepared by introducing A1 and Si into the working layer respectively.After annealing treatment of Mo-Al-C film by 450?,Thin film has complete structure and less carbon loss.The friction coefficient decreases with the increase of annealing temperature.When the Al content is 2.06at%,Mo-Al-C annealing at 450?,the ratio of wear rate is 0.61?6.30×10-16 m3/(N·m).The bond strength of film substrate was HF2?HF4.After annealing treatment of Mo-Al-C film by 450?,Thin film has complete structure and less carbon loss.The bond strength of film substrate was HF1?HF2.Friction coefficient is kept between 0.05?0.12.When the Si content is 8.91at%Ti-Si-C film annealing at 450?,the ratio of wear rate is 0.61?6.30×10-16 m3/(N·m).The Mo-Al-Ti and Ti-Si-C amorphous carbon films did not occur invalid during annealing at 450?.It is showed that double hysteresis mechanism of oxide compound doped can increase the limit thermal service temperature of amorphous carbon film effectively. |
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