纳米填料增强UHMWPE-橡胶水润滑摩擦学性能

Tribological Properties of UHMWPE-Rubber Reinforced by Nano Fillers Under Water Lubricated

为了研究水润滑条件下试验载荷和速度对纳米磷化硅填料(Nano–SiC)改性超高分子量聚乙烯(UHMWPE)–橡胶复合材料摩擦学性能的影响,通过高温混炼、热压成型制备Nano–SiC辅以聚四氟乙烯(PTFE)填充改性UHMWPE–橡胶复合材料;采用MRH–3型环–块摩擦试验机探究4种不同载荷条件下复合材料的摩擦磨损性能,采用光学显微镜(OM)、扫描电子显微镜(SEM)和非接触光学3维轮廓仪对试样微观磨损表面形貌分析,从微观层面探究改性复合材料的摩擦机理。试验结果表明:在定载变速条件下,速度由0.005 m/s升到0.541 m/s时,改性复合材料的动、静摩擦系数均呈现大幅下降趋势,摩擦系数波动归于平稳,黏–滑现象逐渐减弱直至消失。试验载荷和纳米粒子含量的变化与试样摩擦磨损程度呈负相关:在水润滑条件下,随着纳米粒子含量增加,摩擦系数与磨损率均出现明显降低,填充比例5%的复合材料摩擦学性能最佳,摩擦系数整体较UHMWPE–橡胶材料降低35%,磨损率降低46.6%,磨损表面形貌也随之发生改变;随着载荷的增加,复合材料的磨损率从1.25×10^(–6) mm^(3)/(N·m)降至0.40×10^(–6) mm^(3)/(N·m)。Nano–SiC的含量与工况载荷压力对摩擦磨损均存在一定影响,即填充适量Nano–SiC的UHMWPE–橡胶复合材料能减轻黏–滑现象,与一定工况压力下的对偶钢环组成的摩擦配副能有效改善摩擦性能,有利于减小水润滑轴承的磨损,增强传动系统服役寿命。

In order to study the effect of test load and speed on the tribological properties of Nano–SiC modified ultra high molecular weight polyethylene(UHMWPE)–rubber composites under water lubrication condition,Nano–SiC and Polytetrafluoroethylene(PTFE)filled UHMWPE–rubber composites were prepared by high temperature mixing and hot pressing.The friction and wear properties of the composites under four different loading conditions were investigated by MRH–3 ring block friction tester.The micro wear surface morphology of the samples was analyzed by optical microscope(OM),scanning electron microscope(SEM)and non-contact optical three-dimensional profilometer,and the friction mechanism of the modified composites was explored from the micro layer surface.The experimental results show that when the speed increases from 0.005 m/s to 0.541 m/s,the dynamic and static friction coefficients of the modified composites show a significant downward trend,the fluctuation of the friction coefficient is stable,and the stick–slip phenomenon gradually weakens until it disappears.The change of test load and nano particle content are negatively related to the friction and wear degree.Under the condition of water lubrication,the friction coefficient and wear rate decrease obviously with the increase of nano particle content.The composite with 5%filling ratio has the best tribological performance.The friction coefficient and wear rate decrease 35%and 46.6%respectively compared with UHMWPE-rubber,and the worn surface morphology also changes;The wear rate of the composite decreases from 1.25×10^(-6) mm^(3)/(N·m)to 0.40×10^(-6) mm^(3)/(N·m).The results showed that both the con-tent of Nano-SiC and the load pressure have a certain influence on the friction and wear,that is,UHMWPE-rubber composite filled with appro-priate amount of Nano-SiC can reduce the stick-slip phenomenon,and the friction pair composed of the dual steel ring under a certain load pres-sure can effectively improve the friction performance,which is conducive to reducing the wear of water lubricated bearing and enhancing the ser-vice life of ship transmission system.