Preparation And Study On The Friction And Wear Performance Of Biomimetic Porous Polyetheretherketone Composite Materials

Polyether ether ketone(PEEK)is an excellent plastic for special engineering.However,the pure PEEK has a slightly higher friction coefficient,and the thermal conductivity is difficult and the heat accumulation is serious,it likely to lead to the invalidation of the material.And it can not adapt to run at higher speeds and can not be used in a larger load conditions.In order to let the PEEK can be applied to the harsher condition,it needing the compound modification such as organic blend,fiber reinforced,nano and inorganic micro filling to further improve their tribological properties.The main contents and conclusions of this work were summarized as follows.1.Using Molded-Leaching and high temperature vacuum melting technologies prepared the own sweating lubrication wear-resistance porous CF/PTFE/PEEK composites.The effects of porogen(NaCl),PTFE content and the distance between each of two CF layers on porous PEEK composite material structure and tribological behavior were investigated.The results showed that,the porous CF/PTFE/PEEK composite material contained 20%mass fraction PTFE,30%mass fraction NaCl and the distance between each of two CF layers is 0.4mm had the lowest friction coefficient and wear rate.When load was 200N the friction coefficient was 0.0192 decreased 9 times and wear rate was 3.47×10-16m3/Nm that wear resistance increased by 25 times compared with classic CF/PEEK Composites.The research showed that PTFE could form continuous transfer films which reduced the friction coefficient,and the porous structure could store a certain lubricant grease that turned into stable lubricating oil film during sliding,thereby significantly reduced the material wear rate in the friction process.The carbon fiber cloth shows the role of skeleton supporting effect,and also cooperating with PTFE,NaCl to improve the wear resistance of porous PEEK composite material.2.Using Molded-Leaching and high temperature vacuum melting technologies prepared the self sweating lubrication wear-resistance porous ACF/PTFE/PEEK composites.The effects of mesoporous ACF content,micron-pore-forming agent(NaCl)content and load on the tribological properties of composites were investigated.The results showed that,the porous ACF/PTFE/PEEK composite material had the lowest friction coefficient and wear rate when it contained 8%mass fraction ACF and 30%mass fraction NaCl.When the load was 200N,the friction coefficient and wear rate of porous ACF/PTFE/PEEK composite decreased by 86%and 16 times,respectively,in comparison with those of classic CF/PEEK composite.The results also showed that pore-forming agent(NaCl)formed a large number of micron pores that the porous structure could store lubricant grease,companied with mesoporous ACF forming three-dimensional network.Similar as the mechanism of human sweat glands,the stored grease in the composite can form a more stable,continuous lubricating oil film on the sliding surface under the conjuncting effect of the load and temperature.Moreover,ACF can also play the role of network skeleton support to bears the load.Therefore,ACF can play a good self-lubricating and wear resistantance effect in the porous ACF/PTFE/PEEK composites.3.The tribological behaviors of 1-hexyl-3-methylimidazolium tetrafluoroborate ionic liquid lubricated porous PEEK composites have been investigated and the effect of sliding velocity and applied load on tribological properties and the stability of the lubricating oil film have been discussed.It was found that when the sliding velocity is 0.69m/s and the applied load is 250N,the friction coefficient and the wear rate of the ionic liquid lubricated porous sweating ACF/PTFE/PEEK composites reached the minimum,0.0197 and 4.145×10-15m3/Nm,respectively.Thus the friction coefficient fluctuated in a narrow range of 1.62×10-2-2.15×10-2.The study indicated that the ionic liquid showed excellent tribological properties and anti-wear performance,especially at the high sliding velocity and applied load during the process of friction.The reason may be that there formed the uniform and efficient boundary lubricating film due to the tribochemical reaction.In addition,the morphologies of the worn surface and the counterpart surface were observed by using SEM and the materials were characterized with the use of IR.It revealed that there formed the boundary lubricating film which possessed higher carrying capacity and anti-wear properties and consisted of fluoride,etc.Therefore,the investigation effectively improves the carrying capacity and anti-wear properties of the composites.