Study of molten salt corrosion of HK-40m alloy applying linear polarization resistance and conventional weight loss techniques

Cuevas-Arteaga, C.; Uruchurtu-Chavarı́n, J.; Porcayo-Calderón, J.; Izquierdo-Montalvo, G.; González, Jorge Alfonso Murillo

doi:10.1016/j.corsci.2004.03.002

Cited by 43 publications

(31 citation statements)

References 8 publications

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“…Electrochemical techniques for molten salt corrosion can be used to rapidly identify the best-performing alloys. Recently, these techniques have been used for a better understanding of the fundamentals behind the molten salt corrosion mechanisms for thin-film molten salts in gas-turbine engines and electric power generation [7][8][9][10]. Molten-salt corrosion of Inconel 625 (IN625) in salts containing sulfates, oxides, and chlorides at 600°, 700°, and 800°C reported corrosion rates of 1.80 7 0.33, 14.257 2.01, and 26.5471.69 mm/year, respectively.…”

Section: Introductionmentioning

confidence: 99%

Corrosion of alloys in a chloride molten salt (NaCl-LiCl) for solar thermal technologies

Vidal

Tirawat

2016

Solar Energy Materials and Solar Cells

160

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a b s t r a c tNext-generation solar power conversion systems in concentrating solar power (CSP) applications require high-temperature advanced fluids in the range of 600-800°C. Current commercial CSP plants use molten nitrate salt mixtures as the heat transfer fluid and the thermal energy storage (TES) media while operating with multiple hours of energy capacity and at temperatures lower than 565°C. At higher temperatures, the nitrates cannot be used because they decompose. Molten chloride salts are candidates for CSP applications because of their high decomposition temperatures and good thermal properties; but they can be corrosive to common alloys used in vessels, heat exchangers, and piping at these elevated temperatures. In this article, we present the results of the corrosion evaluations of several alloys in eutectic 34.42 wt% NaCl -65.58 wt% LiCl at 650-700°C in nitrogen atmosphere. Electrochemical evaluations were performed using open-circuit potential followed by a potentiodynamic polarization sweep. Corrosion rates were determined using Tafel slopes and Faraday's law. A temperature increase of as little as 50°C more than doubled the corrosion rate of AISI stainless steel 310 and Incoloy 800H compared to the initial 650°C test. These alloys exhibited localized corrosion. Inconel 625 was the most corrosionresistant alloy with a corrosion rate of 2.80 7 0.38 mm/year. For TES applications, corrosion rates with magnitudes of a few millimeters per year are not acceptable because of economic considerations. Additionally, localized corrosion (intergranular or pitting) can be catastrophic. Thus, corrosion-mitigation approaches are required for advanced CSP plants to be commercially viable.

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Section: Introductionmentioning

confidence: 99%

Corrosion of alloys in a chloride molten salt (NaCl-LiCl) for solar thermal technologies

Vidal

Tirawat

2016

Solar Energy Materials and Solar Cells

160

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“…The type of corrosion typical of chromia-forming alloys in molten chlorides when a small amount of oxygen is allowed in the system has been reported to be localized, such as intergranular and pitting corrosion [4,5].Groll et al [4] evaluated the corrosion behavior of steel containers in latent-TES molten eutectic KCl-LiCl from 310°C to 420°C in air and argon with a long-term weight-loss technique up to 4032 h of immersion time.…”

Section: Introductionmentioning

confidence: 99%

“…Potentiodynamic polarization sweep (PPS) is commonly employed to determine the corrosion rate of materials. Before polarizing the sample by applying the cathodic and anodic over-potentials, the system must establish the open-circuit potential (OCP), which is the equilibrium potential for the undisturbed system.The PPS diagrams, which plot the applied potential versus log-scale of measured current density, are used to determine the corrosion current (I corr ) that is found at the interception of the extrapolated linear or Tafel portions of the cathodic and anodic curves (usually found in the linear portions between -250 mV and +250 mV relative to the OCP or corrosion potential (E corr ) of the sample)[5,6,10,25,26].…”

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confidence: 99%

Corrosion resistance of alumina-forming alloys against molten chlorides for energy production. I: Pre-oxidation treatment and isothermal corrosion tests

Vidal

Fernández

Tirawat

et al. 2017

Solar Energy Materials and Solar Cells

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Advanced components in next-generation concentrating solar power (CSP) applications will require advanced heat-transfer fluids and thermal-storage materials that work from about 550°C to at least 720°C, for integration with advanced power-conversion systems. To reach the cost target, less-expensive salts such as molten chlorides have been identified as high-temperature fluid candidates.High-strength alloys need to be identified and their mechanical and chemical degradation must be minimized to be used in CSP applications. Approaches for corrosion mitigation need to be investigated and optimized to drive down corrosion rates to acceptable levels-in the order of tens of micrometers per year-for achieving a long system lifetime of at least 30 years.Surface passivationis agood corrosion mitigation approach because the alloy could then be exposed to both the liquid and the vapor phases of the salt mixture. In this investigation,we pre-oxidized the alumina-forming alloys Inconel 702, Haynes 224, and Kanthal APMT at different temperatures, dwelling times, and atmospheres to produce the passivation by forming protective oxides at the surface. The pretreated alloys were latercorrodedin molten MgCl 2-64.41 wt% KClat 700°C in a flowing Ar atmosphere. We performed electrochemical techniques such as open-circuit potential followed by a potentiodynamic polarization sweep and conventional long-term weight-change tests to down-select the best-performing alloy and pre-oxidation conditions. The best corrosion results were obtained for In702 pre-oxidized in zero air at 1050°C for 4 h. Metallographic characterization of the pre-oxidized alloys and of the corroded surfaces showed that the formation of dense and uniform alumina scale during the pre-oxidation appears to protect the alloy from attack by molten chloride.

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“…Although this type of steel had been studied by other researchers (Ref [6][7][8], the high-temperature mechanical properties have been scantily researched. However, those properties are the most important factors affecting the durability of the high-temperature applications under thermal shock loading.…”

Section: Introductionmentioning

confidence: 99%

High Temperature Mechanical Properties of HK40-type Heat-resistant Cast Austenitic Stainless Steels

Kim

Lee

Jeong

et al. 2009

J. of Materi Eng and Perform

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This work characterized HK40-type, cast austenitic stainless steel, as the W content was varied from 0 to 3.6 wt.%. Analysis of microstructure using optical and scanning electron microscopies showed that the alloys contained relatively large amount of Cr-carbide, Nb-compound, and MnS at the austenite grain boundary. The addition of W promoted the formation of Cr-carbide and affected the high-temperature mechanical properties. According to tension tests carried out at room temperature, 400, 600, and 800°C, the alloys became significantly stronger and brittle as W content increased. The low-cycle fatigue tests showed that fatigue resistance was also increased with W addition, but an excessive amount of W decreased the fatigue resistance. The HK40-type alloys with 2.0 wt.% W exhibited best high-temperature mechanical performances.

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Study of molten salt corrosion of HK-40m alloy applying linear polarization resistance and conventional weight loss techniques

Cited by 43 publications

References 8 publications

Corrosion of alloys in a chloride molten salt (NaCl-LiCl) for solar thermal technologies

Corrosion of alloys in a chloride molten salt (NaCl-LiCl) for solar thermal technologies

Corrosion resistance of alumina-forming alloys against molten chlorides for energy production. I: Pre-oxidation treatment and isothermal corrosion tests

High Temperature Mechanical Properties of HK40-type Heat-resistant Cast Austenitic Stainless Steels

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