Study On Tribological Properties Of Plastic Alloy Bearing Material

Polymer matierial,a promising water lubricated bearing material,with good mechanical and tribological properties,as well as advantages such as high temperature resistance,chemical resistance and radiation resistance,is widely used in producing aerospace parts.It will decrease friction coefficient and enhance wear resistance of ploymer matrix by adding inorganic and organic addictives in polymer matrix.PTFE has extremely low friction coefficient,and MoS2 with unique layered chemical structure is benifical to the form of transfer film.PTFE and MoS2 have been used as addictives to reduce friction.This paper studies the influence of load,velocity and water-lubricated condition on tribological properties of triobopair formed by PEEK and PI composite material with Silicon Nitride.Tribology tests was conducted on MMW-1 vertical multifunctional tribometer.PEEK composite materias used in this test was modified with PTFE,PI was modified by PTFE and MoS2.test load and velovity were set as 30 N,75N,120 N and 0.25m/s,0.5m/s,1m/s respectively.Experimental results show that Si3N4 ball barely has wear and polymer composite has severe wear.Water lubrication has nearly no influence on friction coefficient of PEEK-Si3N4 tribopair,but it increases the wear rates.Friction coefficient and wear rate decrease with the increase of load,while velocity has little influence on friction coefficient.But wear rate of PEEK increase with the increase of velocity.PI-Si3N4 has obviously lower friction coefficient and wear rate.Fricion coefficient of PI-Si3N4 under water is 0.026,far more lower than 0.044(friction coefficient under dry friction coefficient).For PI-Si3N4 tribopair,friction coeficient and wear rate reduce with the increase of velocity,while with the increase of load friction coefficient deceases and wear rate increases.Compared with PEEK,PI composite meterial can form transfer film even under high load and high velocity.Transfer film could be formed on the surface of polymer-Si3N4 to reduce friction during the friction process.After the tests,strip ravines are formed on the surface of polymer and directional transfer film could obviously observed on the surface of Si3N4.Wear mechanisms of PEEK and PI are adhesive wear and plough cut effect.