Sliding Wear Behavior and Wear Effects of HVOF Sprayed Coatings Derived from Conventional, Fine and Nanostructured WC-12Co Powders

摘要

Fine structured and nanostructured materials represent a promising class of feedstock for future applications, which has also attracted increasing interest in the thermal spray technology. Within the field of wear protection, the application of fine structured or nanostructured WC-Co powders in the High Velocity Oxy-Fuel flame spraying technique (HVOF) provides novel possibilities for the manufacturing of cermet coatings with improved mechanical and tribological characteristics. In this study the tribological behavior of HVOF sprayed coatings derived from conventional, fine and nanostructured WC-12Co powders under sliding wear are investigated and the results are compared to C45 steel (Mat.-No. 1.0503). In addition, wear effects on a microscopic level are scrutinized. It has been shown that under optimized spray conditions the corresponding fine and nanostructured WC-12Co coatings are able to obtain significantly higher wear resistance and lower friction coefficients than the conventional coatings. This can be attributed to scaling effects of the microstructure and to the phase evolution of the coating material, which are discussed.