Production and Properties of Oxide Dispersion Strengthened Metal-Matrix-Composite Powders for Thermal Spray Coatings

摘要

Metal-Matrix-Composites (MMCs) are used in a wide range of applications, due to their favourable combination of hardness and toughness. The high-energy ball milling technique was proved to be an effective method for producing MMCs. The milling process is characterized by repeated deformation, breaking and cold welding of powder particles, causing mechanical alloying of the particles. The milled powders show a homogenous submicron-scale microstructure and specific mechanical properties. Thermal Spraying offers sophisticated processes to apply powder materials to almost all technical relevant base materials. High velocity oxy-fuel (HVOF) flame spraying has emerged as a favourable process to achieve coatings that are well bonded to the substrate with minimal porosity and a reduced quantity of undesirable reaction products. This study shows the production characteristics and impact of mechanically alloyed MMCs on the tribological behaviour of HVOF coatings on the basis of Al_2O_3-strengthened NiCr powder. Wear tests at room temperature and up to 800℃ were performed to characterize the wear behaviour at different temperature levels.