Abstract Alumina composites reinforced with acid-treated multiwalled carbon nanotubes (MWCNTs) are prepared, and the tribological properties of the composite are investigated under water-lubricated conditions using a ball-on-disk technique against an alumina ball. The coefficient of friction (COF) in the steady-state region of the composite with acid-treated MWCNTs is found to be 0.06, which is 32–37% lower than that of the monolithic alumina and the composite with pristine MWCNTs. Microstructural observations and in-depth Raman spectroscopy analyses of the disk samples and counterparts before and after the friction tests reveal that the MWCNTs located in pits on the disk surface pull-out and that the resultant MWCNT fragments adhere to the friction surface of the counterparts. The enhanced tribological performance shown in the composite with acid-treated MWCNTs is mainly because the negatively charged functional groups adsorbed on the MWCNTs participate in the hydrogen-bond network of the hydrodynamic lubrication film and lead to acceleration of the transformation from a boundary lubrication regime to a mixed lubrication regime.

中文翻译：

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酸处理碳纳米管增强氧化铝复合材料在水润滑下的摩擦学性能增强

摘要 制备了酸处理多壁碳纳米管（MWCNTs）增强的氧化铝复合材料，并在水润滑条件下使用球盘技术对氧化铝球研究了复合材料的摩擦学性能。经酸处理的多壁碳纳米管复合材料稳态区域的摩擦系数 (COF) 为 0.06，比整体氧化铝和原始多壁碳纳米管复合材料的摩擦系数低 32-37%。摩擦测试前后磁盘样品和对应物的微观结构观察和深入拉曼光谱分析表明，位于磁盘表面凹坑中的 MWCNT 被拉出，并且由此产生的 MWCNT 碎片粘附在对应物的摩擦表面上。