Sliding wear behavior of gas tunnel type plasma sprayed Ni-based metallic glass composite coatings

Ni60Nb20Zr20 glass composite coatings were successfully produced in a single step using gas tunnel type plasma spraying torch. The resultant phases and structures obtained were characterized using X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques, respectively. The sliding wear behavior of the developed metallic glass composite coatings was evaluated under unlubricated condition using Ball-on-Disk (BOD) tribometer. The results showed that minimum amount of metal oxides and intermetallic phases can be obtained in the coatings at intermediate plasma current only. It is evident that the sliding wear rate of the metallic glass composite coating varied with the loading conditions and its amorphous-crystalline composition. The coating produced at a plasma current of 300 A gives the minimum wear rate and friction coefficient during sliding.

► Crystallinity content in the coating is minimum at an optimal plasma current.
► Coating having lower crystallinity exhibited lower friction coefficient.
► Coating produced at 300 A plasma current gives minimum sliding wear.