Ferritic stainless steel for solid oxide electrochemical cells

A ferritic stainless steel with controlled composition addresses oxidation resistance and Cr poisoning in SOFC and SOEC environments by forming a thin Al-based oxide film with partial Cr-based spinel oxides, ensuring durability and conductivity.

JP7740602B1Active Publication Date: 2025-09-17JFE STEEL CORP
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Patent Information

Application Number
JP2025523122
Authority / Receiving Office
JP · JP
Patent Type
Patents
Current Assignee / Owner
Priority Date
2024-05-22
Filing Date
2025-01-07
Publication Date
2025-09-17
Estimated Expiration
2045-01-07

AI Technical Summary

Technical Problem

Existing stainless steels used in solid oxide fuel cells (SOFCs) and electrolysis cells (SOECs) do not provide sufficient oxidation resistance and resistance to Cr poisoning in the environments containing high-temperature water vapor, as they were developed for different conditions.

Method used

A ferritic stainless steel with controlled chemical composition, specifically within ranges for Si, Mn, Cr, Al, and Nb contents, and satisfying equations (1), (2), and (3), to form a thin surface oxide film primarily composed of Al-based oxides with partial Cr-based spinel oxides, enhancing oxidation resistance and electrical conductivity.

Benefits of technology

The steel achieves excellent oxidation resistance and resistance to Cr poisoning in both SOFC and SOEC environments, maintaining electrical conductivity despite harsh conditions.

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Abstract

This stainless steel has excellent oxidation resistance, resistance to Cr poisoning, and electrical conductivity not only in the use environment of SOFCs but also in the use environment of SOECs.The chemical composition is appropriately controlled, in particular, to 0.05 to 0.40 mass% Si, 1.01 to 3.00 mass% Mn, 10.0 to 22.0 mass% Cr, 0.10 to 1.10 mass% Al, and 0.20 to 0.45 mass% Nb, and the relationships of the following formulas (1), (2), and (3) are satisfied. [Mn]+0.50×[Cr]≧7.00 (1) [Mn]+1.67×[Al]≦4.34 (2) [Si]+0.33×[Al]≦0.67 (3)
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Citation Information

Patent Citations

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    JP2008156692A

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    JP2011162863A

  • Ferritic stainless steel for use in fuel reformer and method of manufacturing ferritic stainless steel

    WO2015064739A1

  • Al-CONTAINING FERRITIC STAINLESS STEEL WITH EXCELLENT CREEP CHARACTERISTICS, MANUFACTURING METHOD THEREFOR, AND FUEL CELL MEMBER

    WO2017073094A1

  • Metallic material for solid electrolyte type fuel cell

    JP1995145454A