Preparation And Tribological Properties Of Graphene/TiO₂ Ceramic Films

The Micro-Electro-Mechanical System?MEMS?has the advantages of small size,light weight,low energy consumption,multipurpose integrating and high intelligence,which enable it to possesses the great application future in many fields,such as biomedicine,automotive electronics,aerospace industry,telematic,automatic control cybernation,militarily,agriculture and industry,etc.The running of the MEMS is greatly impacted by the skin-friction force,viscous resistance and surface tension obviously due to the MEMS gap size between friction counterparts at nano scar and the huge specific surface area.Therefore,researching the films which contain the great selflubricating property is important to the development of MEMS.It is necessary to coating the films with excellent mechanical character or chemical activity/ inertness on the surface of the MEMS,such as DLC,SiC,graphene/TiO₂ films and its composite coating.The method will develop the physical and chemical property of MEMS,and increase the stability and life.The graphene/TiO₂?GT?ceramic films have the excellent properties of lubrication,antifriction and abrasion resistant as the solid lubrication films.The main methods to prepare the nano films coating at the substrate surface are sol-gel process,self-assembly process,molecular beam epitaxy.Through the research study,coating single or multi layers film on the substrate surface is a possible effective method to solve the lubricating problem of the MEMS.It is expected to decrease the surface friction coefficient,which under the situation of unchanging the carrying capacity.Considering the above research background,this paper mainly focuses on the surface topography and tribological properties of GT ceramic film.The major contents and consequence of the paper are summarized as following:?1?To analyze the surface properties of GT ceramic films,assure the dispersity of the graphene,and obtain the best proportioning,the GT ceramic films which has the excellent properties were prepared by sol-gel process.The influence of different content graphene added in ceramic films was investigated,the component and the microstructure was analyzed..?2?Atomic force microscope?AFM?,field emission scanning electron microscope?FESEM?,X-ray diffraction?XRD?,UV-vis diffuse reflection spectroscope and Raman spectra?Raman?were used to investigate the structure.The result shows that,a lot of graphene consist in the ceramic films,and interestingly,the GT ceramic films were decorated by graphene nanoplatelets on surface and at interlayer.The graphene nanoplatelets will agglomerate and can be bridge jointed between the fractures,which will increase the integrality of the ceramic films,decrease the surface roughness and give a smoother surface.What's more,after heat treatment,graphene kept non-oxidized.?3?The tribological properties of GT ceramic films were investigated using a reciprocating ball-on-plate configuration.Different graphene solution,layers,load,frictional velocity,temperature were investigated to obtain the tribological properties of GT ceramic films.The result shows that,the frictional coefficient decreased with larger graphene quantity.However,when the graphene solution grew over than 30 mL,the tribological properties kept stable.The abrasive resistance was increased with the increase of layers.And the frictional coefficient reached the minimum at the 2 layers.The frictional coefficient decreased with the increase of load and frictional velocity.But,The frictional coefficient increased with the increase of temperature.?4?The abrasive resistance of GT ceramic films was investigated at 40 g,300r/min and room temperature.The result shows that,the GT ceramic films show the excellent abrasion resistant properties that kept its integrality after 36000 times sliding reciprocating friction.