Abstract: The MoS₂ nano-precursor solution was synthesized by sodium molybdate and thiourea. The nano-powder was obtained by vacuum freeze-drying method under different freezing modes. The morphology and particle size of the nano-powder materials were studied by transmission electron microscope and atomic force microscopy instruments. The results show that the nanometer molybdenum disulfide prepared by vacuum freeze -drying method has a particle size of 25nm -37nm. At the same time, the nanometer molybdenum disulfide was added as an additive to the paraffin oil. The friction performance was measured by a fourball friction tester. The size and friction coefficient of the wear spot were both significantly reduced.

Key words: nano molybdenum disulfide, freeze drying, lubricating oil additive, friction properties