In previous work, it was shown that CaSO₄-induced corrosion can cause significant internal oxidation in single-crystal Ni-based superalloys similar to that observed in field-exposed components when subjected to a bi-thermal exposure (8 h at 1150 °C → 60 h at 871 °C) in air + 30% steam. In this work, the influence of (1) 1150 °C initiation stage temperature, (2) propagation stage temperature, and (3) CaSO₄ deposit mass on the mechanism of CaSO₄-induced corrosion were investigated further. The results of these experiments showed that subsurface depletion of Al and Cr caused by rapid Ca₄Al₆O₁₆S, CaAl₂O₄, and CrS formation due to CaSO₄ corrosion is required for internal oxidation to occur in N5 and N500, but that these alloys can “heal” when held for long durations at 1150 °C due to the enhanced diffusion of Al within the alloy at elevated temperatures.

之前的工作表明，CaSO ₄引起的腐蚀会导致单晶镍基高温合金发生严重的内部氧化，类似于在双热暴露（1150 °C 下 8 小时）下在现场暴露的部件中观察到的情况。 → 871 °C 下 60 小时）在空气 + 30% 蒸汽中。在这项工作中，进一步研究了(1) 1150 °C 起始阶段温度、(2) 扩展阶段温度和(3) CaSO ₄沉积质量对CaSO ₄诱发腐蚀机理的影响。这些实验的结果表明，由于CaSO 的快速 Ca ₄ Al ₆ O ₁₆ S、CaAl ₂ O _{4和 CrS 的形成，导致了 Al 和 Cr 的亚表面耗尽。}N5 和 N500 中发生内部氧化需要 4 号腐蚀，但这些合金在 1150 °C 下长时间保持时可以“愈合”，因为高温下合金内铝的扩散增强_。