CF/PTFE纤维混编织物增强环氧复合材料干摩擦特性

Dry Tribological Property of Carbon/polytetrafluoroethylene Hybrid Fabric Reinforced Epoxy Composite

采用碳纤维与聚四氟乙烯纤维(CF/PTFE)混编织物增强,制备了环氧树脂基自润滑复合材料,研究了钢背衬复合材料与45钢在环-环端面干摩擦状态下的摩擦学特性,考查了纤维织物、摩擦热、载荷、速度对材料摩擦磨损性能的影响,用红外热像仪、热电偶及风冷方式对摩擦副温度进行监控,用激光共聚焦显微镜和扫描电子显微镜对复合材料及偶件磨损面进行了观察与能谱分析.结果表明:与碳织物相比,混编纤维织物大大改善了复合材料的摩擦学性能,改善效果极大依赖于摩擦温度、载荷和速度参数.PTFE纤维磨损后在树脂基体及偶件表面形成减摩型转移膜层,材料表现为疲劳磨损特征.摩擦高温使复合材料摩擦学特性改变,黏结磨损加剧,偶件钢环表面出现氧化磨损,树脂基体塑性流动,摩擦力增大.混编纤维的排布方式影响复合材料的摩擦磨损性能,摩擦面上大量破碎的碳纤维易使偶件表面转移膜受到破坏,复合材料转变为以磨粒磨损为主,减摩主要源于磨屑中的润滑组分.

Carbon/polytetrafluoroethylene （CF/PTFE） hybrid fabric reinforced epoxy resin self-lubricating composite was fabricated. Tribological properties of the composites against 45 steel with a ring-on-ring configuration in dry sliding were studied. Influences of fabric, friction heat, load, sliding velocity on composite tribological properties were discussed. Infrared thermographer, thermocouple and cooling air were used to survey and control the friction pair temperature. Worn surface of composite and its counterpart were investigated with laser scanning confocal microscope and scanning electronic microscope equipped with energy disperse spectroscopy. Test results show that composite reinforced by hybrid fabric had better friction and wear property than composite reinforced by carbon fabric. The operating parameters, i.e. friction pair temperature, load and sliding velocity had postive influence on friction and wear property. Transfer film of PTFE was observed on the worn 45 steel surface. Wear mechanism of the composite was fatigue. Tribological property of composite depended on the temperature of friction pair. Adhesive wear and oxidation wear occurred when the composite heated up to distortion temperature. Plastic flow of the resin matrix occurred and friction force increased. Hybrid fiber configuration had influence on the friction and wear property. The PTFE transfer film was damaged by massive broken carbon fibers and abrasive wear prevailed. Solid lubricant in wear debris played the major role in reducing friction.