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 lifetime of turbine blades. The addition of hafnium, yttrium, zirconium, chromium, platinum, and cobalt improves the 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 an accelerated isothermal corrosion test at 900°C for up to 400 h. To simulate harsh environmental conditions, Na2SO4- and V2O5-containing solutions were applied to the substrate surface. Subsequently, for 1 h, 50 h, 100 h, 200 h, and 400 h exposure times, the oxide layer thicknesses, spallation time, coating layer depletion time, and elemental analysis of each set were analyzed and their performances compared.