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- Hot Corrosion Behavior of Slurry Sprayed Aluminide Coatings in a Simulated Dynamic Molten Carbonate Environment [Comunicação oral]Publication . Audigié, Pauline; Rodríguez Catela, Sergio; Agüero, Alina; Pedrosa, Fátima; Paiva Luís, Teresa; Cunha Diamantino, TeresaABSTRACT: One of the key challenges associated with the use of molten salts in Concentrated Solar Power (CSP) plants is to reduce or even suppress corrosion phenomena occurring at elevated temperatures. Molten nitrate mixtures are currently seen as the most viable storage medium for Thermal Energy Storage. But the upper temperature limit of the currently used “Solar Salt” is restricted by salt decomposition at ~580ºC. Prieto et al. estimated that increasing the temperature to 650ºC could increase the solar-to-electric conversion up to 18.5%, so alternative salts operating at higher temperature are required. Molten carbonates which are less corrosive and allow an operation up to 800ºC are an appealing breakthrough for future CSP plants.
- A direct comparative study of the corrosion behaviour of Si-free and Si-rich slurry aluminide coatings in molten carbonate meltsPublication . Audigié, Pauline; Rodríguez Catela, Sergio; Agüero, Alina; Pedrosa, Fátima; Paiva Luís, Teresa; Cunha Diamantino, TeresaABSTRACT: This study is focused on the evaluation of the hot corrosion behaviour of two low-cost slurry aluminide coatings with and without Si addition deposited on ferritic-martensitic steels, comparing them with uncoated steel, after 1000-h of exposure to Li, K, Na molten carbonates at 650ºC, under static and dynamic conditions with a high linear velocity (1.3 m/s). Both coatings evidenced a high performance increase in comparison with uncoated substrates after exposure in both conditions. Both coatings behaved in a similar way according to the gravimetric results. However, after dynamic exposure, the Si-free aluminide maintained its morphology and composition after 1000 h with α-LiAlO2 as the only corrosion product while the Si-rich coating showed a higher attack extent in the outer part and developed a large quantity of voids at the coating/substrate interface, leading to substrate corrosion.
- Comparison of descaling methods to study the corrosion kinetics of ferritic steels after dynamic exposure to molten carbonatesPublication . Audigié, Pauline; Rodríguez Catela, Sergio; Agüero, Alina; Pedrosa, Fátima; Paiva Luís, Teresa; Cunha Diamantino, TeresaABSTRACT: T91 ferritic-martensitic steel was exposed to Li, Na and K molten carbonates at 650??C under dynamic conditions up to 1000 h. After testing, three descaling methods, two from the ISO8407 and one from the ISO17245 stan-dards were applied to remove the corrosion products and determine the corrosion rates. The two ISO8407 methods were more appropriate although the procedure required several steps to fully remove the corrosion products. The ISO17245 method led to a higher mass loss affecting probably the base material. Oxides identi-fication was performed by XRD following step by step layers removal. Li-, Na-, K-containing oxides and chro-mates/chromites were detected.