Smialek, James L.Gray, Simon2018-10-262018-10-262018-10-25James L. Smialek and Simon Gray. Low temperature hot corrosion screening of single crystal superalloys. Materials, 2018, Volume 11, Issue 11, Article number 20981996-1944https://doi.org/10.3390/ma11112098https://dspace.lib.cranfield.ac.uk/handle/1826/13584Single crystal superalloys were screened in Type II molten (Na,K)-sulfate hot corrosion re-coat tests in air +300 ppm SO2 at 700 °C. They exhibited large 20–40 mg/cm2 weight changes, repeated spallation, and non-protective, 25–50 μm thick corrosion layers after 300 h of testing. Scale cross sections revealed dual outer Ni(Co)O and inner Al(Cr)S-rich corrosion layers. This chemical differentiation was partially consistent with previous models of oxide fluxing, alloy sulfidation, NiO micro-channel diffusion, and synergistic dissolution mechanisms. Broad shallow pits or uniform attack morphologies were consistent with prior studies performed in high >100 ppm pSO2 environments. Higher Mo experimental alloys trended toward more degradation, producing 100 μm thick scales with distinct Al(Cr)S-rich inner layers or 500 μm thick NiO. The aggressive behavior in these environments supports the need for LTHC-resistant coatings for single crystal superalloys.enAttribution 4.0 Internationalhttp://creativecommons.org/licenses/by/4.0/Type II hot corrosionsingle crystal superalloysmolten saltArticle