摘要
采用超声分散法制备出氧化铝、高岭土、氧化硅/聚四氟乙烯复合材料,使用线性往复摩擦磨损试验机对比三种复合材料的摩擦学性能.结果表明:质量分数10%的氧化铝、高岭土能将聚四氟乙烯的磨损率降低约4个数量级,而氧化硅仅能降低约3个数量级.对金属对偶表面形成的转移膜的形貌和化学成分进行分析发现:氧化铝、高岭土/聚四氟乙烯在金属对偶面上形成了高度羧酸盐化的转移膜.用密度泛函理论对三种填料表面上碳氟分子吸附过程进行模拟,结果显示氧化铝、高岭土表面的路易斯酸性位点促进了碳氟分子的脱氟过程,产生了更多的羧酸螯合物的中间产物;氧化硅缺少路易斯酸性位点,因此不能促进高度羧酸盐化的转移膜形成.
Alumina,kaolinite,and silica/polytetrafluoroethylene composites were prepared using the ultrasonic dispersion method.The tribological properties of the three composites were investigated using a linear reciprocating tribometer.The results showed that 10%mass fraction of alumina or kaolinite solely could reduce the wear rate of PTFE by about 4 orders of magnitude,while silica could only reduce it by about 3 orders of magnitude.Analysis of the morphology and chemical composition of the transfer films formed on the metal counterfaces revealed that alumina/polytetrafluoroethylene and kaolinite/polytetrafluoroethylene could form highly carboxylated transfer films.The adsorption of fluorocarbon molecules on the three filler surfaces were further simulated using density functional theory,which showed that the Lewis acidic sites on the surfaces of alumina and kaolinite promoted the defluorination of fluorocarbon molecules and the carboxylated chelation.The results showed that the Lewis acidic sites on the surfaces of alumina and kaolinite promoted the defluorination of fluorocarbon molecules and produced more intermediates for carboxylated transfer film formation,while silica lacked Lewis acidic sites and therefore could not promote the formation of carboxylated transfer films.
作者
叶家鑫
孙魏
刘小君
刘焜
YE Jiaxin;SUN Wei;LIU Xiaojun;LIU Kun(Institute of Tribology,Hefei University of Technology,Hefei 230009,China)
出处
《宁波大学学报（理工版）》
CAS
2021年第6期28-35,共8页
Journal of Ningbo University：Natural Science and Engineering Edition
基金
国家自然科学基金(51875152,51975174,51875153)
中央高校基本科研业务费专项资金(JZ2021HGPA0062).
关键词
高岭土
聚四氟乙烯
转移膜
摩擦学性能
摩擦化学
kaolinite
polytetrafluoroethylene
transfer film
tribological properties
tribochemistry
