The hot corrosion of a nickel-base superalloy, Udimet 700, has been studied in the temperature range 900–950°C. The effect of the amount of Na 2SO4 on the corrosion kinetics was determined. Large weight gains and severe corrosion were associated with two different modes of degradation: (1) formation of large, interconnected sulfides beneath the external scale, and (2) formation of a Na2MoO4-MoO3 melt. The corrosion due to formation of the Na2MoO4-MoO3 melt occurred for all the salt-coating thicknesses, whereas, large sulfides were formed only for the heavier coatings of Na2SO4. The formation of Na2MoO4-MoO3 melt required an induction period, and the length of the induction period was observed to be a function of the amount of Na2SO4 and of temperature.
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Work funded under NASA Grant NCC 3-43.
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Misra, A.K. Studies on the hot corrosion of a nickel-base superalloy, Udimet 700. Oxid Met 25, 129–161 (1986). https://doi.org/10.1007/BF00655894
- nickel-base superalloy
- hot corrosion
- sodium sulfate