High temperature oxidation of Ni alloys in CO2 containing impurities. (15th August 2019)

• Record Type: Journal Article
• Authors: Oleksak, Richard P.; Tylczak, Joseph H.; Holcomb, Gordon R.; Doğan, Ömer N.
• Is Part Of: Corrosion science. Volume 157(2019)
• Page Start: 20
• Page End: 30
• Publication Date: 2019-08-15
• Subjects: A. Nickel -- A. Superalloys -- C. High temperature corrosion -- C. Oxidation -- C. Selective oxidation -- CO2 power cycle; Corrosion and anti-corrosives -- Periodicals; 620.11223
• DOI: 10.1016/j.corsci.2019.05.019
• Languages: English
• ISSNs: 0010-938X

Abstract

Highlights: Several Ni alloys were exposed to CO2 containing impurities at 1 atm and 750 °C. Protective chromia layers formed regardless of H2 O, O2, and SO2 impurities. Little or no carburization, sulfidation, or chromia volatilization occurred. Si was beneficial, and Ti detrimental, to alloy oxidation resistance. The evolving microstructure of the alloy surface promoted chromia formation/growth. Abstract: Next-generation power systems require structural alloys resistant to high-temperature oxidation in CO2 containing combustion impurities. Here we evaluate the oxidation performance of several commercial Ni alloys exposed to 95%CO2 -4%H2 O-1%O2, with/without 0.1% SO2, at 750 °C and 1 atm. All alloys formed protective chromia layers and showed no signs of carburization or sulfidation, and minimal chromia volatilization. The microstructural evolution of the alloy surface, secondary oxidants, and minor alloy additions all played a role in promoting protective chromia formation/growth. The results show that Ni alloys are promising candidates for high-temperature portions of next-generation CO2 -based power systems.