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. (C) 2012 Elsevier B.V. All rights reserved.