Fabrication of Ag-WS2 composites with preferentially oriented WS2 and its anisotropic tribology behavior

The Ag-WS2 composites with preferentially oriented WS2 flakes were successfully prepared via freeze casting and followed spark plasma sintering. The cross-sectional morphology and the XRD spectra showed that the WS2 flakes in Ag-WS2 composites were arranged in a preferred orientation along base plane (0 0 2). Based on this unique oriented structure, Ag-WS2 composites exhibited notably anisotropic tribology behavior when sliding along the direction parallel or perpendicular to the (0 0 2) plane of WS2. Compared to the parallel-plane, the friction coefficient and wear rate of the perpendicular-plane were increased by 30% and 167%, respectively. Additionally, the preferred orientation method of particles can also be applied to prepare other composites with oriented structure.