Synergistic water lubrication effect of self-assembled nanofilm and graphene oxide additive

In this study, a pretreatment method was proposed to enhance the lubrication effect of GO as additives. During pretreatment, 3-aminopropyltriethoxysilane (3-APS) nanofilm was successfully fabricated on substrate surface by self-assembled technique. The 3-APS nanofilm with amino groups can chemically adsorb the GO nanosheets in water. Thus the graphene oxide sheets could deposit on 3-APS nanofilm quickly and last longer, forming durable tribofilms on sliding contact areas. Scanning electron microscope (SEM), energy-dispersive spectroscopy (EDS) and water contact angle (WCA) characterizations revealed the successful preparation of 3-APS nanofilm. Importantly, tribological investigations indicated that under the synergistic effect of 3-APS nanofilm and GO additives, the friction coefficient and the wear rate decreased by 43.6% and 79.7%, compared to those of albronze lubricated by deionized water. Control experiments by respectively using GO additive, and 3-APS nanofilm were performed as well. It is found that using 3-APS nanofilm and GO additives together exhibits the best tribological performances among all the samples. Furthermore, GO tribofilms were detected on wear tracks and relative lubricating mechanisms were elucidated.