Surface Treatments for Improved Performance of Spinel-coated AISI 441 Ferritic Stainless Steel

Technical Report · Tue Jan 01 00:00:00 EST 2013

DOI:https://doi.org/10.2172/1068652· OSTI ID:1068652

Stevenson, Jeffry W; Riel, Eric M; Stephens, Elizabeth V; Khaleel, Mohammad A

Ferritic stainless steels are promising candidates for IT-SOFC interconnect applications due to their low cost and resistance to oxidation at SOFC operating temperatures. However, steel candidates face several challenges; including long term oxidation under interconnect exposure conditions, which can lead to increased electrical resistance, surface instability, and poisoning of cathodes due to volatilization of Cr. To potentially extend interconnect lifetime and improve performance, a variety of surface treatments were performed on AISI 441 ferritic stainless steel coupons prior to application of a protective spinel coating. The coated coupons were then subjected to oxidation testing at 800 and 850°C in air, and electrical testing at 800°C in air. While all of the surface-treatments resulted in improved surface stability (i.e., increased spallation resistance) compared to untreated AISI 441, the greatest degree of improvement (through 20,000 hours of testing at 800°C and 14,000 hours of testing at 850°C) was achieved by surface blasting.

• Research Organization: Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 1068652
• Report Number(s): PNNL-22191; AA2530000
• Country of Publication: United States
• Language: English