The microstructure and tribological properties of liquid-fuel HVOF sprayed nanostructured WC–12Co coatings

A nanostructured WC–12Co composite coating was prepared by applying the liquid-fuel HVOF spray technique. The microstructure and composition of tungsten carbide nanopowder were analyzed with a scanning electron microscope (SEM) and a transmission electron microscope (TEM). The investigations revealed that the sizes of the original particles were in the range of 50–500 nm. The nanostructured coatings had denser structure and higher hardness than the conventional coating. The content of W2C, WC1 − x, W and of amorphous phase was also smaller. The coefficient of friction for the HVOF-sprayed nanostructured WC–12Co coating was four times lower than that for the conventionally sprayed WC–12Co coatings. Finally, the nanostructured coating showed higher abrasive resistance than the conventionally sprayed coatings.