Corrosion characteristics of a nickel-base alloy C-276 in harsh environments. (3rd August 2017)

• Record Type: Journal Article
• Authors: Li, Yanhui; Wang, Shuzhong; Yang, Jianqiao; Xu, Donghai; Guo, Yang; Qian, Lili; Song, Wenhan
• Is Part Of: International journal of hydrogen energy. Volume 42:Number 31(2017)
• Page Start: 19829
• Page End: 19835
• Publication Date: 2017-08-03
• Subjects: Nickel-base alloy -- C-276 -- High-temperature air -- Supercritical water -- Oxidation kinetic -- Oxide scale; Hydrogen as fuel -- Periodicals; Hydrogène (Combustible) -- Périodiques; Hydrogen as fuel; Periodicals; 665.81
• DOI: 10.1016/j.ijhydene.2017.05.243
• Languages: English
• ISSNs: 0360-3199

Abstract

Abstract: The oxidation behaviors of alloy C-276 in two harsh environments: high-temperature air and supercritical water (SCW), respectively representing the working conditions of the external and internal surfaces of reactors for SCW gasification biomass to produce H2, were investigated. In two environments, all oxidation kinetics followed parabolic laws, while the corrosion rate of alloy C-276 exposed to supercritical water gasification (SCWG) environments was 2.5–3 times higher than that in high-temperature air. The oxide scale formed in air at 500 °C consisted of an outer Fe-rich layer (Fe2 O3 and NiCr2 O4 ) and an inner layer of Cr2 O3 and NiCr2 O4, while the outer Fe-rich layer disappeared as the temperature increased to 550 °C. Compared to the scales formed on nickel-base alloys in near-pure SCW, the absence of NiO and Ni(OH)2 phases within the scales formed on the C-276 samples in present SCWG environment may be due to higher molar proportion of hydrogen. Highlights: Corrosion behaviors of alloy C-276 in high-temperature air and SCW. Oxidation activation energy of approximate 229.74 kJ/mol in air at 450–550 °C. Corrosion rate of C-276 in SCWG is about 2.5–3 times higher than that in air. In SCWG, the outer layer of scales: Ni/Fe-rich spinel particles. The absence of NiO and Ni(OH)2 in the outer layer due to higher hydrogen content.