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 degrees 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.

Automated summary

This study develops an automated protocol for analyzing and comparing the effects of three deposits on the accelerated non-uniform degradation of a model alloy at high temperature. The Ca-containing mixed oxide deposit increases oxide intrusions into the alloy, while the CaSO4 and Ca-containing mixed sulfate deposits form less-protective calcium aluminates and increase the roughness of the alloy-TGO interface. The mixed sulfate deposit melts and spreads, resulting in more uniform attack.