| Abstract Scope |
Hot section turbine components are subjected to aggressive operational conditions. One resulting consequence is deposit corrosion or deposit-induced corrosion in which constituents of ingested atmospheric matter result in deposit formation on critical components. This presentation focuses on our current work on two compounds of interest in deposits - calcium oxide and calcium sulfate. Calcium oxide can react with protective oxide scales such as chromia or alumina to form calcium chromates or aluminates, leading to solute depletion in the alloy and degradation of the external protective scale. Additionally, at high enough temperatures, calcium sulfate can decompose into calcium oxide and sulfur trioxide, causing sulfidation in addition to the calcium-enhanced corrosion. These concerns are more pronounced in the case of chromia formers, which can form eutectics with melting points below operating temperatures. In this study, Ni-Cr alloys were subjected to corrosion under calcium-containing deposits. Post-test characterization enabled insights into degradation mechanisms. |