Study On Tribological Properties Of UHMWPE Composites Filled With CSW

UHMWPE is a widely used engineering plastic for it's versatile and excellent properties, such as good self-lubrication, erosion resistance,wearing resistance etc. However, its'application in wear and friction circumstance were restricted by some shortcomings such as lower facial hardness and poor abrasive wear-resistance. In this thesis, CSW and nano-Al₂O₃ filled UHMWPE composites were prepared and the modification effect of these fillers to the hardness and tribological properties of the obtained composites were studied.Filled composites were prepared following the traditional physical mixing and hot-pressing procedures. The friction and wear behavior of the obtained composites disks were investigated on a high-temperature & atmosphere QG-700 model tester against AISI1045 steel ball under dry sliding condition. The worn Micro-morphology of the composites'surfaces was recorded by SEM. The element chemistry of the worn surface was analyzed by EDS alpha ray spectrometer. The wear scar widths were observed by 3D morphology meter. The facial hardness of the materials was measured by Shore durometer.The results show that the addition of the CSW filler can effectively increase the hardness and tribological properties and lower the friction coefficient of the UHMWPE/CSW composites. The wearing resistance and the friction coefficient of the UHMWPE/CSW composites increase with the load and the sliding speed increasing. With the filling rate of the CSW fillers increasing, the abrasion mechanism of the UHMWPE/CSW composites changed from adhesive wear and thermoplastic deformation to slight abrasive wear. The optimal filling rate of CSW filler in composites is about 20%. The CSW fillers play a certain role in the heterogeneous nucleation.Comparing with the CSW, nano-Al₂O₃ fillers have the similar positive effect in improving the hardness and tribological properties of the UHMWPE/nano-Al₂O₃ composites. Nano-Al₂O₃ can lower the friction coefficient of the obtained composites. The optimal filling rate of nano-Al₂O₃ filler in composites is about 20%. The abrasion mechanism of the UHMWPE/nano-Al₂O₃ composites are adhesive wear. A few minor scratches were founded on the worn surface.The two-component filler system, made of Al₂O₃ and CSW, was founded having positive mutual effect in promoting the hardness and the wearing resistance of the corresponding composites. The micron-scale CSW fillers play a role in bearing and distributing the external load and the generated internal stress were further dispersed by the smaller nano-scale Al₂O₃ filler. The optimal filling ratio of the two-component is separately nano-Al₂O₃ 3% and CSW 20%. At this filling ratio, the transfer film can be effectively generated on the AISI1045 steel ball friction surface. These results indicate that multi-component filler systems are promising ways to improving tribological properties of the composites and worth further study.