Preparation And Tribological Properties Of Complex Textured PTFE Surfaces By Embossing And Thermal Annealing

Surface texture can play a role in reducing friction and abrasion,improving surface lubrication,etc.,and is widely used in bearings,cylinders,seals and other mechanical parts.However,most of the applications are surface textures with simple patterns,because of the factors such as preparation form,process,efficiency,cost and so on.It is of great significance for the development of tribology theory and the research of new high-performance components to explore the low-cost and efficient method for preparing complex pattern textures,studying their friction and wear properties and related mechanisms.Fabric has low cost and textured surface adjusted by textile structure parameters,which can be used as a template to prepare complex pattern texture.In this paper,a PTFE surface with a complex texture was prepared by embossing which uses a fabric as a template and thermal annealing.The morphology of the surface was characterized by three-dimensional topography measuring instrument,scanning electron microscope,etc.The influence of preparation technology,textures,working conditions and water environment on friction and wear performance of the PTFE surface textures and related mechanism were studied by pin-disk tribology tester,three-dimensional topography measuring instrument,etc.The research indicates:(1)The thermal annealing temperature has a significant effect on the morphology of the PTFE surface texture,while the molding pressure and holding time have little effect on the morphology of the PTFE surface texture.The best preparation process is a molding pressure of 35 MPa,a thermal annealing temperature of 345°C,and a holding time of 180 min.Molding pressure,thermal annealing temperature and holding time have no significant effect on the friction coefficient and wear depth of the PTFE surface texture.(2)The fabric template significantly affects the texture of the PTFE surface,and the texture significantly affects the friction coefficient and wear depth of the PTFE surface texture.When the warp density and weft density of the fabric template are equal,the protrusions on the PTFE surface texture are point-shaped,otherwise they are strip-shaped.The strip-shaped protrusions have stronger abrasion resistance than the point-shaped protrusions.(3)The law of the change of friction coefficient and the law of the change of wear depth of the PTFE surface texture with the working conditions are the same.The larger the load,the larger the friction coefficient and the wear depth of the PTFE surface texture;the larger the sliding speed,the larger the friction coefficient and the wear depth of the PTFE surface texture.The best working conditions are a load of 5N and a sliding speed of 5cm/s.(4)Compared with dry friction,the friction coefficient and wear depth of the PTFE surface texture are smaller in the water environment,and the friction coefficient and wear depth of the PTFE surface texture are not affected by its hydrophobicity.The thermal annealing temperature significantly affects the hydrophobicity of the PTFE surface texture.When the thermal annealing temperatures are 345°C and 360°C,the PTFE surface texture is superhydrophobic.