Probing High-Temperature Electrochemical Corrosion of 316 Stainless Steel in Molten Nitrate Salt for Concentrated Solar Power Plants

Singh, MP and Basu, B and Chattopadhyay, K (2022) Probing High-Temperature Electrochemical Corrosion of 316 Stainless Steel in Molten Nitrate Salt for Concentrated Solar Power Plants. In: Journal of Materials Engineering and Performance, 31 (6). 4902 -4908.

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Abstract

The corrosion resistance of structural materials, particularly in molten salt environments, is of central importance to design concentrated solar power (CSP) plants. In this perspective, the high-temperature electrochemical behavior of passive film on 316SS in solar salt composition (60 pct. NaNO3: 40 pct. KNO3 by wt. pct.) was evaluated using linear resistance polarization, Tafel polarization, and electrochemical impedance spectroscopy techniques in the application range of 400 to 550 °C. An increase in corrosion rate with temperature and severe oxidation at 550 °C was recorded. However, the corrosion potential (Ecorr) does not vary significantly. The critical analysis of the impedance bode phase diagram reveals two well-separated maxima at 400 °C, indicating the role of the passive layer during the corrosion process. At 500 °C, the observed phase angle is close to 45°, attributed to processes controlled by mass transfer limitations. While analyzing the influence of mass transfer, an equivalent circuit model has been proposed to analyze the corrosion of the 316SS, a material used for piping and containment of CSP plants in molten solar salt.

Item Type:	Journal Article
Publication:	Journal of Materials Engineering and Performance
Publisher:	Springer
Additional Information:	The copyright for this article belongs to the Springer.
Keywords:	Austenitic stainless steel; Corrosion rate; Corrosion resistance; Corrosive effects; Electrochemical corrosion; Equivalent circuits; Fused salts; High temperature corrosion; Mass transfer; Molten materials; Polarization; Potash; Potassium Nitrate; Sodium nitrate; Solar energy; Solar power plants; Steel corrosion, 316 stainless steel; Concentrated solar power; Electrochemical behaviors; Electrochemical-impedance spectroscopies; High-temperature electrochemical; Molten salt; Nitrate salts; Passive films; Salt composition; Solar salt, Electrochemical impedance spectroscopy
Department/Centre:	Division of Chemical Sciences > Materials Research Centre Division of Interdisciplinary Sciences > Interdisciplinary Centre for Energy Research Division of Mechanical Sciences > Materials Engineering (formerly Metallurgy)
Date Deposited:	08 Jul 2022 10:00
Last Modified:	08 Jul 2022 10:00
URI:	https://eprints.iisc.ac.in/id/eprint/74331

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