This paper examines the bonding mechanisms of high-speed flame spraying (HVOF) sprayed coatings on the basis of the experiments with the substrate at different surface roughness. In order to determine the dominant adhesion mechanisms of HVOF layers, the layers are applied to substrates of different roughness with completely melted powder particles as well as with powder particles with solid and liquid phases. The spray materials are NiCrBSi and WC-Co. The results of adhesion tests showed that the adhesion of the NiCrBSi layer on the roughened substrate was approx. 40 MPa, while there was no adhesion on the polished substrate. In contrast, the adhesive strength of the WC-Co layer on the polished substrate was already between 20 and 40 MPa. The adhesive strength of the WC-Co layers on the substrate with a roughness greater than 5.8 micrometer already exceeded that of the binder materials. Paper includes a German-language abstract.