Kim Ji-Hyun, Kim Won Seok, Yoo Yungchul
Convergence Research Division, Korea Carbon Industry Promotion Agency, Jeonju 54853, Jeonbuk, Korea.
Material and Component Convergence R&D Center, Korea Construction Equipment Technology Institute, Gunsan 54004, Jeonbuk, Korea.
Materials (Basel). 2022 Jun 7;15(12):4054. doi: 10.3390/ma15124054.
Bushes are circular bearings that surround a shaft and help it rotate smoothly. In heavy equipment, bushes are coated with solid lubricants to reduce friction. Although the coating layer of the lubricant has a stable coefficient of friction (CoF), it is important that this should last for a long time. In this study, multiwalled carbon nanotubes (MWCNTs), which have a low CoF, were added to the lubricant to improve its performance. When 2.3 wt% MWCNTs were added to the polymer resin, the dynamic CoF (under a 29 N external load) decreased by 78% in relation to that of the resin without MWCNTs. As the MWCNT content increased, the roughness of the coating decreased, which reduced the CoF. Moreover, MWCNT addition increased the overall tensile strength owing to an increase in the bonding force between the resins. Under a high load of 20 tonnes (t), the MWCNT-based solid lubricant had a CoF of 0.05, lower than commercial MoS-based solid lubricants; this was maintained for more than 10,000 cycles in a bush and shaft test. With the MWCNT-based solid lubricant, a lubricating polymer film formed, even on worn bush surfaces. The CoF of the solid lubricant was reduced and the number of cycles with a constant CoF increased when MWCNTs were added owing to the formation of the lubricating polymer film.
衬套是围绕轴的圆形轴承，有助于轴平稳旋转。在重型设备中，衬套涂有固体润滑剂以减少摩擦。尽管润滑剂的涂层具有稳定的摩擦系数（CoF），但重要的是这种涂层应能长期保持。在本研究中，添加了具有低摩擦系数的多壁碳纳米管（MWCNT）以改善润滑剂的性能。当向聚合物树脂中添加2.3 wt%的MWCNT时，动态摩擦系数（在29 N的外部负载下）相对于未添加MWCNT的树脂降低了78%。随着MWCNT含量的增加，涂层的粗糙度降低，从而降低了摩擦系数。此外，由于树脂之间结合力的增加，添加MWCNT提高了整体拉伸强度。在20吨（t）的高负载下，基于MWCNT的固体润滑剂的摩擦系数为0.05，低于商用的基于MoS的固体润滑剂；在衬套和轴的测试中，这一摩擦系数在超过10000次循环中保持稳定。使用基于MWCNT的固体润滑剂时，即使在磨损的衬套表面也会形成润滑聚合物膜。由于润滑聚合物膜的形成，添加MWCNT后，固体润滑剂的摩擦系数降低，且在恒定摩擦系数下的循环次数增加。
