Atomic Origins of Water-Vapour-Promoted Alloy Oxidation

Journal Article · Mon May 07 00:00:00 EDT 2018 · Nature Materials

DOI:https://doi.org/10.1038/s41563-018-0078-5· OSTI ID:1495038

Luo, Langli ; Su, Mao; Yan, Pengfei; Zou, Lianfeng; Schreiber, Daniel K.; Baer, Donald R.; Zhu, Zihua; Zhou, Guangwen ; Wang, Yanting ; Bruemmer, Stephen M.; Xu, Zhijie; Wang, Chongmin

The presence of water vapor, intentional or unavoidable, is crucial to many materials applications, such as steam generator, turbine engine, fuel cell, catalyst, and corrosion 1-6. Phenomenologically, water vapor has been noticed to accelerate oxidation of metals/alloys 7,8, however, the atomistic mechanisms remain elusive. Herein, through direct in situ atomic-scale transmission electron microscopy observation and density functional theory calculation, we reveal that water vapor enhanced oxidation of Ni-Cr alloy is associated with proton dissolution promoted vacancy formation, migration and clustering. Protons derived from water dissociation occupy interstitial position in the oxide lattice, which consequently leads to the lowering of both vacancy formation energy and the cation diffusion barrier. The atomic scale observations reveal a water vapor derived proton mediated oxide growth mechanism, which provides insights for reckoning many technological processes concerning materials in moist environment at elevated temperatures.

• Research Organization: Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 1495038
• Report Number(s): PNNL-SA-124752
• Journal Information: Nature Materials, Vol. 17, Issue 6; ISSN 1476-1122
• Publisher: Springer Nature - Nature Publishing Group
• Country of Publication: United States
• Language: English