A novel preparation method for MoS2 nanosheets with good tribology performance by the combination of expansion and freeze exfoliation

Two-dimensional MoS2 nanosheets were exfoliated by the combination of high temperature expansion exfoliation (MoS2-OA) and low temperature freeze exfoliation (MoS2-OA-N-2). The samples were verified by XRD, Raman, UV vis, FT-IR, SEM, TEM, HRTEM and AFM. The results indicated that the MoS2-OA-N-2 nanosheets with 5-7 layers were small size, few layers and thin thickness. The formation mechanism of the MoS2-OA-N-2 nanosheets was proposed. Furthermore, the lubrication performances of the MoS2-OA-N-2 nanosheets in base oil were tested on the four-ball wear machine. The average friction coefficient (COF) and average wear scar diameter (AWSD) of 0.08 wt% MoS2-OA-N-2-based oil were about 26.46% and 44.55% lower than those of the base oil. The results exhibited that the MoS2-OA-N-2 showed the excellent tribological properties.