A new method to improve homogeneity and oxidation stability of Cu nanoparticles for lubricant additive in liquid phase reduction process

Abstract

Abstract In the preparation of Cu nanoparticles by liquid phase reduction, the traditional reagent mixing mode was changed to improve the homogeneity in Cu nanoparticle size. In addition, Cu nanoparticles were collected by adding the volatile organic solvent (benzine) to the reaction system to prevent the oxidation of them. XRD and SEM analysis confirmed that the reaction products were spherical Cu particles with relatively uniform size of 30–50 nm. EDS analysis showed that the oxygen content in the product was 36.2% for using a centrifuge and 12.6% for using benzine, indicating that the oxidation of Cu nanoparticles was relatively prevented in the preparation process. The lubricant containing Cu nanoparticles of 0.15 wt% exhibited decreased friction coefficient by 60% compared the pure lubricant. Moreover, the decreasing tendency of friction coefficient of the Cu nanoparticles prepared by the proposed method was more stable than that of Cu nanoparticles prepared by the common liquid phase reduction process.