Development of oxide dispersion strengthened MCrAIY powder by high energy ball milling

MCrAIY-materials are widely used as bond coat for thermal barrier coatings on turbine blades. Scope of this work is to improve mechanical properties of thermal sprayed MCrAIY-coatings by strengthening the employed powder feedstock with hard phase particles. In order to retain the effect of the dispersion reinforcement at high temperatures, the use of temperature-stable oxide hard phases (ZrO2) is necessary. For realisation of this new material structure the high energy ball milling process is applied and analysed. The high-energy ball milling technique is an effective method for producing powders for MMCs [1]. With this process it is possible to achieve a homogeneous distribution of the oxide dispersoid (ZrO2) in the NiCoCrAlY matrix. In order to receive an optimal mixing ratio between these two materials, different compositions were produced and analysed. Furthermore the influences of the milling time of the high energy ball milling process on the distribution of the hard phases in the metal matrix were analysed. Special attention was given to the particle size distribution after milling, as it plays an important role during processing with thermal spray processes, because it significantly affects the microstructure and therefore the mechanical properties of the coatings. After spraying with the High Velocity Oxy-Fuel Flame Spraying (HVOF) process the properties of the coatings were measured and compared with conventional NiCoCrAlY coatings.