Selection of corrosion-resistant materials for use in molten nitrate salts

Tortorelli, P.F.; Bishop, P.S.; DiStefano, J.R.

doi:10.2172/5236321

Cited by 14 publications

(24 citation statements)

References 4 publications

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“…This can be correlated to the dissolution of Cr at the oxide‐salt interface. Cr is the most soluble species in nitrate salts . On the other hand, Na‐penetration is evident at the outer part of the scale and very localized at the inner scale (see Figures and 7).…”

Section: Discussionmentioning

confidence: 95%

“…Cr is the most soluble species in nitrate salts. [5,10] On the other hand, Napenetration is evident at the outer part of the scale and very localized at the inner scale (see Figures 5 and 7). The composition at this zone does not show any stoichiometric ratio.…”

Section: Effective Reactions In Solar Salt Corrosionmentioning

confidence: 96%

“…Therefore, the appropriate material selection and life time estimation requires intensive hot corrosion studies considering different aspects of corrosion environment and material behavior. Recently, corrosion behavior of the common structural materials such as carbon steels, low‐Cr steels, stainless steels, and in some cases Ni‐base alloys have been studied …”

Section: Introductionmentioning

confidence: 99%

“…Recently, corrosion behavior of the common structural materials such as carbon steels, low-Cr steels, stainless steels, and in some cases Ni-base alloys have been studied. [5][6][7][8][9][10] At high temperatures molten solar salts act as ionic electrolytes leading to the transportation of oxidizing agents to the metal and dissolution of metal ions into the salts. Commercial salts of different sources may contain various levels of impurities such as carbonates, chlorides, and sulfides.…”

Section: Introductionmentioning

confidence: 99%

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High temperature corrosion in molten solar salt: The role of chloride impurities

Dorcheh

Durham

Galetz

2017

Materials & Corrosion

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The role of chloride impurities in molten NaNO3‐KNO3 (solar salt) mixture on corrosion behavior of low‐chromium ferritic‐martensitic X20CrMoV11‐1 steel (X20) and stainless steel 316 (SS316) was studied at 600 °C. Gravimetric and metallographic methods were employed to characterize the kinetics of oxidation and the resulting corrosion products. Steel X20 showed non‐protective character in both low‐ (up to 0.02 wt% Cl−) and high‐ (up to 0.25 wt% Cl−) chloride salts by forming a thick and non‐compact oxide scale. A significant increase in weight gain was observed when X20 steel was immersed in the high‐chloride‐containing salt. Furthermore, the scale underwent severe deformation. SS316 showed superior corrosion resistance in both low‐ and high‐chloride salts. Oxide scales formed on both steels included two zones: an outer Na‐rich oxide and an inner mixed oxide based on Fe2O3 and Fe3O4 structures. The morphology and composition of these zones were significantly different on X20 and SS316 steels. A passive Cr‐rich oxide layer at the metal/oxide interface was characterized as a protective layer. In the case of stainless steel 316 this layer showed even higher continuity when tested in the high‐chloride salt resulting in better protection during the isothermal test.

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Section: Discussionmentioning

confidence: 95%

Section: Effective Reactions In Solar Salt Corrosionmentioning

confidence: 96%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

High temperature corrosion in molten solar salt: The role of chloride impurities

Dorcheh

Durham

Galetz

2017

Materials & Corrosion

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“…More importantly, both decomposition reactions result in an increased concentration of oxidizing agents in the salt melt, which is basically an ionic electrolyte at higher temperatures and conveys oxidizing agents to metallic surfaces, while metal cations can be dissolved into the salt melt [2,10,13]. For instance, Cr is a stable oxide former for various industrial applications; however, Cr cations present in the Cr-rich oxide scales can further oxidize and form chromate or dichromate species (e.g., via Reaction 3 [7,15]) that are highly soluble in the molten salt [9,11,16]. The formation of these species not only increases the extent of Cr-depletion, but also generate major environmental and health issues due to chromates being highly toxic [6].…”

Section: Introductionmentioning

confidence: 99%

Scale Formation and Degradation of Diffusion Coatings Deposited on 9% Cr Steel in Molten Solar Salt

et al. 2019

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The employment of ferritic-martensitic steels e.g., P91, as structural materials in concentrated solar power (CSP) plants can significantly increase cost-efficiency. However, their application is strongly restricted by their lower corrosion resistance in molten nitrates, compared to austenitic steels or Ni-based alloys. In this study, Cr-, Al-, and Cr/Al-diffusion coatings were deposited on P91 via pack cementation in order to improve its scaling behavior in molten solar salt (MSS). The corrosion behavior of coated specimens was investigated with respect to uncoated P91 in MSS at 600 °C for up to 1000 h. The exposure in MSS resulted in a thick, highly porous, and multi-layered oxide scale on uncoated P91 consisting of hematite, magnetite, and sodium ferrite. On the other hand, the scale grown on the chromized P91 comprised of a thin Cr-rich inner layer, which shifted breakaway to prolonged exposure durations. The aluminized specimens both formed very thin, highly protective alumina scales with localized protrusions.

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Influence of elemental composition in environmental impacts of steel

Batuecas

Mayo

Díaz

et al. 2019

J. Iron Steel Res. Int.

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The environmental behavior of four steels was analyzed. In the operation phase of concentrating solar power plants, steels withstand high temperature because of its contact with molten salts. Hence, choosing the steel type for the molten salt tanks remains a great challenge. In the cold tank, carbon steel is usually used although an approach with low chromium content steel is being studied for these applications. Likewise, in high temperature applications, such as hot store tank, austenitic stainless steel is the most frequent choice. However, ferritic steel is being considered as a promising material in these applications. As many researchers studied the steel technical properties without considering their environmental damages, this work aimed to introduce the environmental aspects into the material choice by using the life cycle assessment technique. On one hand, the results showed the environmental adequacy of carbon steel against low chromium content steel. On the other hand, the results obtained in those steels suitable in high temperature application revealed significant environmental benefits from the ferritic steel instead of the austenitic steel.

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Selection of corrosion-resistant materials for use in molten nitrate salts

Cited by 14 publications

References 4 publications

High temperature corrosion in molten solar salt: The role of chloride impurities

High temperature corrosion in molten solar salt: The role of chloride impurities

Scale Formation and Degradation of Diffusion Coatings Deposited on 9% Cr Steel in Molten Solar Salt

Influence of elemental composition in environmental impacts of steel

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