Study on lubricating oils containing mixtures additives of nano-CaCO3 and nano-Cu

The nano-CaCO3 and nano-Cu particles was selected as mixtures additives of lubricating oils. The suitable surfactants were selected ,and lubricating oils with mixtures of nanoparticles of CaCO3 and Cu were prepared. Their tribological properties were tested in four-ball tribotester. The surface morphology of wear scar were examined by scanning electron microscope (SEM). The nanoparticles morphology and distribution on worn surfaces were analyzed by atomic force microscope (AFM) and scanning electron microscope (SEM). The research results show that, the optimal additive volume and proportion of nanoparticles are: mass fraction of mixtures of nanoparticles of CaCO3 and Cu is 0.6%, and their mass fraction ratio is 1 : 1; and this lubricating oil has excellent tribological properties. The optimum tribological properties of mixtures of nanoparticles of CaCO3 and Cu in lubricating oils may be related with existing states of nanoparticles on surfaces.