Short-carbon-fiber-reinforced polyetherimide (SCF/PEI) composites have good mechanical properties and are expected to have wide applications including components serving under water lubrication conditions. However, no work has been reported on the tribological behaviors of SCF/PEI composites under water lubrication conditions. This work attempts to explore the practicality of the SCF/PEI composite from a tribological point of view under water lubrication conditions. SCFs are coated by polydopamine (PDA) to enhance the interfacial interaction between fibers and matrix. The tribological performances of SCF/PEI composite are systematically investigated by sliding wear tests under tap and sea water lubrication conditions. Experimental results show that the SCF/PEI composite has a better friction performance in water lubrications than that under dry sliding because of the separation effects formed by a water molecule film and a transfer film. However, no remarkable differences of wear resistance are found between water lubrication and dry contact conditions, and the magnitude of specific wear rate under these conditions is around 1 × 10⁻⁶ mm³/N·m. It is found that contact surface hardness of the SCF/PEI composite is reduced after a sliding test in water due to the plasticization phenomenon, especially sea water can accelerate the diffusion of water molecules into matrix, making the specific wear rate in sea water is ten times of that in tap water for highly-loaded conditions. Meanwhile, the abrasive wear is observed to be the dominated wear mode in boundary lubrication regime, and the adhesion wear occurs around the transition position from the boundary to mixed lubrication regime. It is also found that pressure has a significant effect on the temperature rise within the contact surface than the speed does. Finally, the tribological performance of the SCF/PEI composite under water is exhibited to be better than that of most of polymers and composites reported previously.

短碳纤维增强聚醚酰亚胺（SCF/PEI）复合材料具有良好的机械性能，有望得到广泛的应用，包括在水润滑条件下工作的部件。然而，没有关于 SCF/PEI 复合材料在水润滑条件下的摩擦学行为的报道。这项工作试图从摩擦学的角度探索 SCF/PEI 复合材料在水润滑条件下的实用性。SCF 涂有聚多巴胺 (PDA)，以增强纤维和基质之间的界面相互作用。通过在自来水和海水润滑条件下的滑动磨损试验，系统地研究了 SCF/PEI 复合材料的摩擦学性能。实验结果表明，由于水分子膜和转移膜形成的分离效应，SCF/PEI复合材料在水润滑下的摩擦性能优于干滑动下的摩擦性能。然而，水润滑和干接触条件下的耐磨性没有显着差异，这些条件下的比磨损率的大小约为 1 × 10⁻⁶ 毫米³/牛·米。发现SCF/PEI复合材料由于塑化现象在水中滑动试验后接触面硬度降低，尤其是海水能加速水分子向基体的扩散，使得在海水中的比磨损率为10在高负荷条件下，是自来水中的两倍。同时，观察到磨粒磨损是边界润滑状态下的主要磨损模式，粘附磨损发生在边界润滑状态到混合润滑状态的过渡位置附近。还发现与速度相比，压力对接触表面内的温升具有显着影响。最后，SCF/PEI 复合材料在水下的摩擦学性能优于之前报道的大多数聚合物和复合材料。