Development of Oxide Dispersion Strengthened MCrAlY Coatings

MCrAlY materials are widely used as bond coats for thermal barrier coatings on turbine blades. The aim of this work is to improve mechanical properties and wear resistance of thermal sprayed NiCoCrAlY-coatings by strengthening the coating 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 such as ZrO2-Y2O3 is necessary. To realize this new material structure, the high-energy ball-milling process is applied and analyzed. The mixture ratio between NiCoCrAlY and ZrO2-Y2O3 was varied between 5 and 10 wt.% ZrO2-Y2O3. 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 analyzed. After spraying with a HVOF system the mechanical properties of the coatings are measured and compared with conventional NiCoCrAlY coatings.