粉状纤维增强PTFE复合材料的力学与摩擦磨损性能

MECHANICAL AND FRICTIONAL PROPERTIES OF PTFE COMPOSITES FILLED WITH POWDERED FIBERS

以粉状SiC纤维、Al2O3纤维、高强碳纤维(CF)、中强CF、低强CF增强聚四氟乙烯(PTFE),研究了纤维种类、含量对PTFE力学和摩擦磨损性能的影响,用扫描电子显微镜(SEM)对试样拉伸断口形貌进行观察,探讨了复合材料的增强机理。结果表明,粉状SiC纤维、Al2O3纤维及CF均能提高PTFE的硬度和耐磨性;高强CF、中强CF及Al2O3纤维能提高其拉伸强度;5种纤维均使PTFE冲击强度下降,但PTFE/高强CF复合材料的冲击强度降幅较小;SEM分析表明,SiC纤维与PTFE的界面结合强度较低,界面出现了许多空隙,中强CF、高强CF、Al2O3纤维与PT-FE界面结合较好,拉伸断口处多数纤维与基体牢固粘附而难以拔出,PTFE/低强CF复合材料呈典型的脆性断裂特征。

The Polytetrafluoroethylene （PTFE） was filled with powdered SiC fiber, Al2O3 fiber, high-strength carbon fiber （CF） , medium-strength CF and low-strength CF. The effects of types and content of fillers on the mechanical, friction and wear properties of PTFE were investigated. The tensile fracture surfaces were observed by a scanning electron microscope （SEM）. The strength- en mechanism of composites was investigated. The results indicated that the hardness and wear resistance of PTFE were raised when powdered SiC fiber, Al2O3 fiber, CF were filled in. The tensile strength of PTFE filled with high-strength CF, medium-strength CF and Al2O3fiber were increased. Five fiber fillers reduced impact strength of PTFE and PTFE/high-strength CF had smaller decline. The micro-analysis of tensile fracture surface showed that interface bonding strength between SiC fiber and PTFE was lower. There existed a number of gaps on the interface. The interface bonding between the high-strength CF, medium-strength CF, Al2O3 fiber and PTFE matrix was better. And most of fibers was a solid adhesion in matrix and could not be pulled out on tensile fracture surface, The PTFE/ low-strength CF composite assumed typical brittle character.