The Study of the Inhibitive Behavior of COF-5 Lubricant Additives on Wear and Corrosion of the Tin Bronze Friction Pair during the Current-Carrying Process

Abstract

COF-5 is an excellent choice as a lubricant additive due to its high specific surface area and regular layer stacking structure. In this paper, the porous covalent organic frameworks of the COF-5 nanomaterial were successfully synthesized as a lubricant additive via a method of sonochemical synthesis. Pure [BMIM][SCN] (BS) was used as the base oil, and the tribological properties of the COF-5-BS composite lubricant were evaluated by using a ball-on-disk wear tester. The results were demonstrated that the wear volume of BS with the addition of 0.1 wt % COF-5 was reduced by 46.64% as compared to that of the pure BS, and the corrosion on the friction interface was effectively inhibited by the addition of COF-5 nanomaterial. This phenomenon was ascribed to COF-5 with a large specific surface area, being adsorbed onto the friction interface, which could repair the wear-induced pits and prevent the direct contact between the metal substrate and the corrosive medium. The tribological properties of the COF-5-BS composite lubricant could be efficiently regulated under the applied electric current. The results of intelligent electric current-controlled friction were indicated that the average coefficients of friction (COF) under the current stimulation of 30 mA with on/off cycling were reduced by 12.05% as compared to that of a continuous current operated for 1 h. Moreover, the wear volume and depth were reduced by 11.69% and 8.75%, respectively. That is because the short duration of current regulation could enhance the rapid formation of a lubricant film composed of BS liquid and COF-5 nanosheets on the friction interface. Meanwhile, the temperature on the interface would not be high to produce the failure of lubricating film, resulting in an excellent low friction coefficient and excellent antifriction property.