Tribological Behaviors Of Doped Diamond-like Carbon Films Under The Slutions

It is difficult to avoid friction and wear among mechanical systems.The reduction of friction and wear between moving parts is of great significance for reducing energy consumption and increasing the service lives of equipment.DLC film,as a common solid lubricant,is greatly restricted in application due to the high internal stress and the difficulty of replacement in service conditions.Contrary to solid lubricants,liquid lubricants are less restricted by the environment and can obtain very good lubrication effect under macroscopic conditions.However,liquid lubricants always fail to effect under some extreme working conditions.The solid-liquid composited lubrication can combine the advantages of both solid lubricants and liquid lubricants to make up the limitations of single lubrication method.The different elements doped films(F-DLC,N-DLC and Si-DLC)with different elements(nearly 3.5 at.% and 10 at.%)are prepared by plasma enhanced chemical vapor deposition(PECVD).The solid-liquid composited superlubricity can be realized under the action of alcohol solution and phosphoric acid solution respectively.Scanning electron microscope,Raman spectroscopy and X photoelectron spectroscopy are utilized to characterize the structure of the films.Frictional properties of films are characterized by UMT,optical microscopy and 3D profile analysis.The results are as follows:1.Prepare the doped DLC films(F-DLC,Si-DLC and N-DLC)with similar element content(3.5 at.%,10 at.%),and explore the influence of bonding method and structure when the other element doped.When the element content in the film is about3.5 at.%,element doping has little effect on the films.And the content of doping elements in the film is 10 at.% or so,the element doping has greater effect on the films.It provides a new way to explore the microstructure of DLC film,and deepens our understanding of DLC film bonds.2.The solid-liquid composited friction experiment can be realized under the action of the doped DLC film and ethanediol at room temperature.The results showed that the Si doped DLC films possess the best friction property.Then the changes of the film interface before and after friction and the tribochemical reaction are analysed.The microscopic mechanism of the superlubricity is revealed: when the element content nearly at 10 at.%,the production of reaction on the surface of the Si-DLC film can greatly reduce the shear force among the contact area,thereby achieving superlubricity and low wear.It is of great significance to further study the solid-liquid composited superlubricity of alcohol lubricants.3.DLC films with similar element content(3.5 at.%)are prepared by different precursors.And investigate the influence of doped elements on the solid-liquid composite superlubricity properties of the film under the reaction of phosphoric acid.It can be find that a proper content of silicon can promote the tribochemical reaction of the silicon and phosphoric acid,then the solid-liquid composite superlubricity can be achieved at low content of silicon.It provides the theoretical support for the lubrication research of the acid-based lubricant in the field of mechanical equipment.