改性碳纤维的制备及其增强PTFE复合涂层摩擦学性能

Preparation of Modified Carbon Fiber and Its Influence on Tribological Properties of PTFE Composite Coating

以磷酸二氢铝(AP)为粘结剂,采用喷涂-热固法制备的聚四氟乙烯(PTFE)复合涂层硬度不高,抗磨性能差,填充碳纤维(CF)能显著改善涂层的综合性能。为提高CF与涂层界面强度,通过双-[γ-(三乙氧基硅基)丙基]四硫化物(Si69)偶联剂对CF表面进行改性处理,制得改性碳纤维(MCF)。利用FTIR、EDS和SEM对改性前后CF的组成、元素及形貌进行表征。利用摩擦磨损试验机和扫描电子显微镜对填充不同MCF含量的PTFE复合涂层的摩擦学性能进行研究。结果表明:Si69偶联剂成功接枝到CF表面,使得CF表面粗糙化,增强了碳纤维与复合涂层界面结合强度;MCF能显著改善涂层摩擦学性能,且随着MCF的含量增加,涂层的硬度和耐磨性能明显提高;涂层的摩擦因数随着MCF含量的增加有所增大,在涂层中填充质量分数为4%的MCF时,涂层综合摩擦学性能最好,其硬度达到12.5 HV,摩擦因数为0.091,磨损率仅为2.24×10^(-4)mm^(3)/(N·m),且涂层表面均匀致密。

Polytetrafluoroethylene(PTFE)composite coating prepared with aluminum dihydrogen phosphate(AP)as the binder by the spray-thermosetting method shows low hardness and poor wear resistance.Carbon fiber(CF)was added into the coating as a filler to improve the comprehensive performance of the coating.In order to improve the interface bond between CF and the coating,CF was modified by bis-[γ-(triethoxysilyl)propyl]tetrasulfide(Si69)coupling agent to obtain modified carbon fiber(MCF).FTIR,EDS and SEM were used to characterize the composition,elements and morphology of CF before and after modification.In addition,the tribological properties of PTFE composite coatings reinforced with different content of MCF were studied using a tribological tester and a scanning electron microscope.Results show that the Si69 coupling agent is successfully grafted to the surface of CF,which roughens the surface of CF and enhances the bond between CF and the coating.Besides,MCF can significantly improve the tribological properties of the coating.With the increase of MCF,the hardness and wear resistance of the coating are significantly improved.The friction coefficient of the coating slightly increases with the increase of MCF.The coating shows the best tribological performance via adding 4%MCF(mass friction).Its hardness reaches 12.5 HV,the friction coefficient is 0.091,and the wear rate is only 2.24×10^(-4)mm^(3)/(N·m).Besides the coating surface is uniform and dense.