Toward a Comprehensive Mechanistic Understanding of Hydrogen Uptake in Zirconium Alloys by Combining Atom Probe Analysis With Electronic Structure Calculations
Paper i proceeding, 2015

The ability of a zirconium alloy to resist corrosion relies on a compromise between two opposing strategies. Minimizing the hydrogen pickup fraction (HPUF) by invoking metallic electron conduction in the barrier oxide results in rapid parabolic oxide growth. On the other hand, slow sub-parabolic barrier oxide growth, as reflected in rate limiting electron transport, may result in a high HPUF. The objective of the present study is to offer mechanistic insights as to how low concentrations of different alloying elements become decisive for the overall corrosion behavior. Combining atomistic microanalysis with first principles modeling by means of density functional theory, the speciation and redox properties of Fe and Ni towards hydrogen evolution are firstly explored. Complementary atom probe microanalysis at the metal–oxide interface provides evidence for Fe and Ni segregation to grain boundaries in Zircaloy-2 that propagates into the ZrO2 scale. Descriptors for how alloying elements in ZrO2 control electron transport as well as catalytic electron-proton recombination in grain boundaries to form H2 are determined by means of theory. The findings are generalized by further atomistic modeling, and are thus put in the context of early reports from autoclave experiments on HPUFs of zirconium with the alloying elements Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, and Nb. A shunting mechanism which combines inner and outer hydrogen evolution mechanisms is proposed. Properties of the transient zirconium sub-oxide are discussed. A plausible atomistic overall understanding emerges.

density functional theory

corrosion

zirconium

atom probe tomography

HPUF

hydride

alloys

hydrogen pickup

suboxide

HPU

Författare

Mikaela Lindgren

Chalmers, Kemi och kemiteknik, Energi och material, Oorganisk miljökemi

Gustav Sundell

Chalmers, Teknisk fysik, Materialens mikrostruktur

Itai Panas

Chalmers, Kemi och kemiteknik, Energi och material, Oorganisk miljökemi

Lars Hallstadius

Mattias Thuvander

Chalmers, Teknisk fysik, Materialens mikrostruktur

Hans-Olof Andrén

Chalmers, Teknisk fysik, Materialens mikrostruktur

ASTM 17th International Symposium on Zirconium in the Nuclear Industry, Hyderabad, Andhra Pradesh, India, 3-7 February 2013

0066-0558 (ISSN)

Vol. STP 1543 515-539

Drivkrafter

Hållbar utveckling

Ämneskategorier

Energiteknik

Annan fysik

Annan materialteknik

Teoretisk kemi

Nanoteknik

Korrosionsteknik

Den kondenserade materiens fysik

Styrkeområden

Energi

Materialvetenskap

Fundament

Grundläggande vetenskaper

DOI

10.1520/STP154320120164

ISBN

978-0-8031-7529-7

Mer information

Skapat

2017-10-07