Tribological behavior of RF sputtering WS2 thin films with vacuum annealing

Thin films of tungsten disulfide (WS2) were deposited on 3Cr13 martensitic stain less steel substrate by RF sputtering. The as-deposited films were annealed at 200,400 and 600 °C for 2 h in vacuum. The vacuum degree was 510-4 Pa. Composition, surface morphology, structure properties and tribological behavior were studied by EDS, SEM, X-ray diffraction techniques and tribometer, respectively. At 200 °C, the films showed low crystallization structure and the tribological behavior was not improved obviously. But at 400 °C, the films tribological behavior were improved obviously and non-crystalline to hexagonal structural transition appeared. When annealing temperature rose to 600 °C, the films were desquamated from substrate. The results suggested that suitable vacuum annealing was able to promote crystallization and improve tribological performance of RF sputtering WS2 films.