Title: High-temperature corrosion of a nickel-based alloy in a molten chloride environment – The effect of thermal and chemical purifications

Abstract

There is currently an ever-increasing demand for higher process efficiencies in next generation (Gen3) concentrating solar power (CSP). Higher process efficiencies may be procured by increasing the operating temperature, and simultaneously, minimizing the degradation of materials used for construction of CSP plants (e.g., piping, thermal storage tanks, solar receivers and heat exchangers). Thus, understanding materials corrosion in the presence of molten salt mixtures used as thermal energy storage media and heat transfer fluids is indispensable for CSP development. The present paper provides insights into the effects of salt purification on the corrosion of a nickel-based alloy (Haynes 230) isothermally exposed to a stagnant chloride-based salt mixture at 800 °C. The MgCl₂-based salt mixture was thermally dehydrated and chemically treated with (0.1 and 0.5 wt %) elemental magnesium. Results reveal the electrochemical nature of the corrosion process, and the formation of corrosion products such as oxides (MgO, MgCr₂O⁴, and MgAl₂O₄) and nitrides (CrN) on the alloy surface and in sub-surface regions. Magnesium additions enhanced the ability to resist corrosion by reducing the concentration of impurities (H₂O, MgOH⁺, OH^- species) and polarizing the alloy surface. The formation of nitrides in all cases studied indicates the impact of using nitrogen as a protectivemore » gas in the system. Results also reveal that a single step treatment of the salt using metallic Mg could be considered as a measure to control the salt's impurity level, e.g., if required for system control.« less

Authors:

Mortazavi, Anna ^[1]; Zhao, Youyang  ^[2];

• Search DOE PAGES for author "Zhao, Youyang"
• Search DOE PAGES for ORCID "0000-0003-0727-3258"

Esmaily, Mohsen ^[3]; Allanore, Antoine ^[3]; Vidal, Judith  ^[2];

• Search DOE PAGES for author "Vidal, Judith"
• Search DOE PAGES for ORCID "0000-0002-0591-3250"

Birbilis, Nick ^[4]

---

+ Show Author Affiliations

1. Harvard Univ., Cambridge, MA (United States)
2. National Renewable Energy Lab. (NREL), Golden, CO (United States)
3. Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)
4. Australian National Univ., Canberra, ACT (Australia)

Publication Date:

Thu Dec 16 00:00:00 EST 2021

Research Org.:

National Renewable Energy Laboratory (NREL), Golden, CO (United States)

Sponsoring Org.:

USDOE Office of Energy Efficiency and Renewable Energy (EERE), Renewable Power Office. Solar Energy Technologies Office; USDOE Office of Science (SC), Office of Workforce Development for Teachers and Scientists (WDTS), Community College Internship (CCI) Program and Science Undergraduate Laboratory Internship (SULI) Program

OSTI Identifier:

1839592

Report Number(s):

NREL/JA-5700-81249
Journal ID: ISSN 0927-0248; MainId:82022;UUID:5fc45a2c-86b1-4b11-9602-41094fafbf79;MainAdminID:63557

Grant/Contract Number:  

AC36-08GO28308

Resource Type:

Accepted Manuscript

Journal Name:

Solar Energy Materials and Solar Cells

Additional Journal Information:

Journal Volume: 236; Journal ID: ISSN 0927-0248

Publisher:

Elsevier

Country of Publication:

United States

Language:

English

Subject:

14 SOLAR ENERGY; 36 MATERIALS SCIENCE; cathodic protection; concentrating solar power; high-temperature corrosion; magnesium; oxidation and nitridation