Approach for statistical analysis of oxide- and sulfate-induced hot corrosion of advanced alloys

This work develops an automated image and statistical analysis protocol to characterize and compare the effect of three deposits on the accelerated non-uniform degradation of a model alloy (FeCrAlY) at 1025 °C in dry air. Compared to the sample tested without a deposit, the Ca-containing mixed oxide deposit increased the frequency of oxide intrusions into the alloy. The CaSO4 and Ca-containing mixed sulfate deposits reacted with the thermally grown oxide (TGO) to form less-protective calcium aluminates and increased the roughness of the alloy-TGO interface. However, the mixed sulfate deposit melted and spread, increasing the uniformity of the attack.