Microstructure and formation mechanism of nanostructured WC-12Co coatings deposited by plasma flame spray

The precursor of WC-12Co nano-composite powder is synthesized by the larruping method of spray drying and fixed bed technique, nanostructured WC-12Co cermet coatings are deposited by plasma flame spray. Microstructure of nanostructured WC-12Co cermet coatings is evaluated by u-sing X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The nano-composite WC-12Co powders generally contain WC and Co, whereas the phases W₂C, W and Co₃C, Co₃W₉C₄, Co₃W₃C/amorphous binder phases based on Co and nano-twins occur in coatings, the mechanism of formation of nanostructured WC-12Co cermet coatings is discussed on the basis of the microstructure in this paper.