Significance of Experimental Procedures on the Hot Corrosion Behavior of Nickel-Base Alloys Under Cyclic Conditions
- ORNL
A simplified test procedure was established to assess the hot corrosion behavior of MCrAlY-type nickel-base alloys under the influence of molten sodium sulfate as well as sodium sulfate/potassium sulfate salt mixtures. Salt coated specimens were exposed to lh thermal cycles at 950°C in flowing oxygen for up to 500 cycles. Mass change data of the specimens revealed a significant dependence of the corrosion attack not only, as expected, on the average contaminant flux rate, but also on the initial amount of salt deposited during each recoating cycle. Furthermore, deposit removal before salt recoating was found to markedly influence the corrosion attack of the alloys. This was related to changes in salt chemistry by the dissolution of elements such as Cr from the alloy which shifted the basicity of the salt and thus affected the extent of attack. Substituting Na for K in sodium sulfate/potassium sulfate salt mixtures enerally resulted in a decreased attack. Although the high K-containing salts still caused significant attack typical of Type-I hot corrosion, the overall degration was much less than for sodium sulfate alone.
- Research Organization:
- Oak Ridge National Laboratory (ORNL), Oak Ridge, TN
- Sponsoring Organization:
- USDOE Office of Industrial Technologies (OIT) (EE-20)
- DOE Contract Number:
- AC05-96OR22464
- OSTI ID:
- 9231
- Report Number(s):
- ORNL/CP-103227; ED 20 01 00 0; ON: DE00009231
- Country of Publication:
- United States
- Language:
- English
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