A Comparative Analysis of Ternary Element Addition on Corrosion Behavior of Aluminide Coatings in Harsh Environmental Conditions

Increasing hot corrosion durability of aluminide coatings is important to extend the life-time of turbine blades. The addition of hafnium, yttrium, zirconium, chromium, platinum and cobalt improves performance of aluminide coating by increasing oxide adherence and selective oxide formation rate. In this research, the effect of adding ternary elements (Y, Cr, Y/Cr, Zr, and Hf) on Type-1 hot corrosion behavior of aluminide coatings was investigated by accelerated isothermal corrosion test at 900 °C for up to 400 hours. To simulate harsh environmental conditions, Na2SO4 and V2O5 containing solutions were applied to substrate surface. Subsequently, for 1, 50, 100, 200 and 400 hours exposure times, the oxide layer thicknesses, spallation time, coating layer depletion time, and elemental analysis of each set were analyzed and their performances compared to each other