Abstract:The microstructure of the interface between the high velocity oxygen-fuel flame (HVOF) sprayed WC-Co coating and spring steel substrate was characterized by electron microscopy. The WC particles embedded in the adheringγphase of nanometer crystallites were observed in the WC-Co coating. A 2μm thick diffusive layer of tungsten atoms is present in the spring steel substrate, which implies that atomic movements between the ceramic coating and the metal substrate occur during the HVOF spraying and that may be the main reason of excellent bond between the HVOF sprayed WC-Co coating and the spring steel substrate.

Key words: high velocity oxygen-fuel flame spraying　microstructure　interface