Hot Corrosion Behaviour of Incoloy 800H Superalloy with Various Molten Salts Environment

Abstract

AbstractEnergy storage is one of the promising concepts to manage with increased energy demand. Among the wide options, thermal energy storage technology plays a superior role with multiple base technologies. Molten salts with high melting point and boiling point are used to retain the thermal energy observed from concentrated solar plants. Metals such as superalloys are used for storing the molten salts, since hot corrosion may lead to storage material rupture. In this present study, among the wide spread of superalloys, nickel-based superalloy—Incoloy 800H—is used as the storage material. Due to its high heat retaining capacity, melting point and boiling point, salts such as mixture of sodium and potassium chloride, sodium sulphate and calcium carbonate have been taken up for this investigation. All the salts were heated for the aggressive temperature to 1000 ℃ approximately for different hours with Incoloy 800H specimens. After heating the specimens, mechanical testing such as tensile test and hardness test was performed and material characterization such as porosity test, scanning electron images and X-ray diffraction analysis was performed. All the test results were compared in this investigation. From the results obtained, it could be inferred that the specimens heated with sodium sulphate molten salt are highly affected and the minimal amount of corrosion is found in specimens heated with calcium carbonate and sodium and potassium chloride molten salts.KeywordsIncoloy 800HMolten saltsSodium sulphateCalcium carbonateSodium and potassium chloride salts