Abstract:Calcium carbonate nanoparticles were synthesized via coprecipitation method in the presence of oleic acid.The morphologies and structure of the products were characterized by scanning electron microscopy(SEM),Xray diffraction(XRD) and Fourier transform infrared spectroscopy(FTIR).Results show that spherical vaterite calcium carbonate nanoparticles with an average size of 30 nm are prepared.The dispersion stability of calcium carbonate nanoparticles in rapeseed oil was studied,and the tribological properties of the calcium carbonate nanoparticles as an additive in rapeseed oil were evaluated with a fourball tester.The results show that these calcium carbonate nanoparticles have good dispersivity in rapeseed oil,and the dispersion stability is also improved.The calcium carbonate nanoparticles possess good performance in friction-reduction and anti-wear in rapeseed oil,because the Ca in CaCO3 nanoparticles is deposited on the worn steel surface in the process of friction,which can prevent the steeltosteel direct contact.