ISSN   1004-0595

CN  62-1224/O4

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纤维材质对UHMWPE水润滑轴承复合材料摩擦学性能的影响

Effect of Fiber Material on Tribological Properties of UHMWPE Water-Lubricated Bearing Composites

  • 摘要: 超高分子量聚乙烯(Ultra-high molecular weight polyethylene, UHMWPE)在水润滑轴承领域具有巨大的发展潜力,然而单一的UHMWPE难以满足水润滑轴承的耐磨性需求,尤其是在低速重载工况下. 通过纤维改性的方法可以提高其摩擦学性能,但是纤维材质的不同特性对于复合材料摩擦学性能的影响存在差异. 通过热压模具分别制备剑麻纤维(Sisal fiber,SF)、碳纤维(Carbon fiber,CF)和聚酯纤维(Polyester fiber,PETF)与UHMWPE混合的定向纤维复合材料,并与纯UHMWPE做对照试验. 利用R-tec往复摩擦试验机模拟不同载荷(5和10 N)和不同速度(20、40和60 mm/s)下铜球与不同复合材料的摩擦过程,通过邵氏硬度和极限抗弯强度试验对复合材料力学性能进行表征测试,采用接触角测试复合材料的浸润性,试验结束后用扫描电子显微镜观察表面磨损形貌. 结果表明:纤维的力学性能,尤其是硬度和抗弯强度是影响定向纤维复合材料摩擦学性能的关键因素,所添加纤维在复合材料中强有力的支撑作用使摩擦学性能显著提高,纤维的耐磨性和浸润性是次要因素. 试验工况下,CF/UHMWPE摩擦系数最低,且在低速重载(载荷10 N,速度20 mm/s)时的摩擦系数与纯UHMWPE相比降低了36.92%;添加耐磨性强的PETF纤维后,复合材料磨损体积与纯UHMWPE相比降低了30.56%.

     

    Abstract: Ultra-high molecular weight polyethylene (UHMWPE) has the advantages of excellent self-lubricating properties, low friction coefficient, and high toughness, making it highly promising in the field of water-lubricated bearings. However, low wear resistance and low strength make it difficult for single UHMWPE to meet the wear resistance requirements of water-lubricated bearings, especially under low-speed heavy load operating conditions. Many domestically and internationally studies have shown that adding fiber materials with excellent properties to the base material can improve the tribological properties of the base material. However, the characteristics of fibershighly affect the tribological properties of the manufactured composites. Therefore, it is necessary to study oriented fiber composites made with different fibers to explore the most suitable fibers. In this study, oriented fiber composite materials were prepared by hot pressing Oriented fiber composites of sisal fiber (SF), carbon fiber (CF) and polyester Fiber (PETF) mixed with UHMWPE were prepared by a hot pressing mold. Rtec tribol-tester had been used to carried out the tribological experiments, the friction process between a copper ball and different composite materials was carried out under different loads (5, 10 N) and speeds (20, 40, 60 mm/s). The mechanical properties of the composite materials were tested through Shore hardness and ultimate flexural strength tests. The wettability of the composite materials was tested using a contact angle test, and the wear surface topography was observed using the scanning electron microscope after the test. The results showed that the effect of fiber materials on the tribological properties of composite materials highly depending on their characteristics. The mechanical properties of the fibers, especially hardness and flexural strength, were the key factors affecting the tribological properties of oriented fiber composite materials. The strong supporting role of added fibers in composite materials significantly improved the tribological properties, while the wear resistance and wettability of the fibers were secondary factors affecting the tribological properties of composite materials. Under the experimental conditions, the CF/UHMWPE composite material had the lowest friction coefficient during the friction process with the copper ball. Compared with pure UHMWPE, the CF/UHMWPE composites presented the highest reduction in the friction coefficient, which reached to 36.92% under low speed heavy load operating conditions (10 N, 20 mm/s). This was mainly due to the excellent mechanical properties of carbon fiber, which helped to reduce the friction coefficient of the composite material. In addition, carbon powder, which formed after carbon fiber was worn, could act as a lubricating medium on the surface of the friction pair and further reduced the friction coefficient. The wear volume of the PETF/UHMWPE decreased by 30.56% compared to pure UHMWPE, due to the excellent wear resistance and compressive strength of PETF.

     

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