Development of alloyed and dispersion-strengthened MCrAlY coatings

Abstract An on-going research program has investigated the effects of the separate and combined additions of Ta, Pt and an oxide dispersion to basic MCrAlY overlay coatings. The goals were improved oxidation and hot corrosion resistance, greater diffusional stability, and coating thermal expansion reduction in order to be closer to nickel base turbine blade alloys. It was found in cyclic burner rig testing at 1050°C that each individual addition improved resistance of the baseline compositions. Oxide and Pt additions reduced thermal expansion. Creep resistance was greatly increased by oxide additions, which also strongly increased yield strength. Yield strength was modestly increased by Pt at low temperature and significantly increased by Ta at low to moderate temperatures.