Abstract
Nanostructured materials have a high potential to improve properties of thermal spray coatings. High-energy ball milling is an effective process to produce dispersion-strengthened powders with a homogenous nanoscale microstructure and superior mechanical properties compared to unstrengthened material. Because of the relatively low temperatures and heat flux during HVOF spraying, the microstructure of the powder particles can be maintained in the coating. In this study Al2O3- dispersion-strengthened NiCr powders were synthesised by high-energy ball milling, using optimised milling parameters. Thermal spray coatings were produced using the HVOF process. The improvement of the tribological behaviour and the potential for technical applications were evaluated. The study shows the favourable impact of mechanically alloyed MMCs on the tribological behaviour of HVOF coatings on the basis of an Al2O3-strengthened NiCr powder