Structure evolution of h.c.p./c.c.p. metal oxide interfaces in solid-state reactions

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216208%3A11310%2F18%3A10382165" target="_blank" >RIV/00216208:11310/18:10382165 - isvavai.cz</a>

Result on the web

<a href="https://doi.org/10.1107/S205327331800757X" target="_blank" >https://doi.org/10.1107/S205327331800757X</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1107/S205327331800757X" target="_blank" >10.1107/S205327331800757X</a>

Result language

angličtina

Original language name

Structure evolution of h.c.p./c.c.p. metal oxide interfaces in solid-state reactions

Original language description

The structure of crystalline interfaces plays an important role in solid-state reactions. The Al2O3/MgAl2O4/MgO system provides an ideal model system for investigating the mechanisms underlying the migration of interfaces during interface reaction. MgAl2O4 layers have been grown between Al2O3 and MgO, and the atomic structure of Al2O3/MgAl2O4 interfaces at different growth stages was characterized using aberration-corrected scanning transmission electron microscopy. The oxygen sublattice transforms from hexagonal close-packed (h.c.p.) stacking in Al2O3 to cubic close-packed (c.c.p.) stacking in MgAl2O4. Partial dislocations associated with steps are observed at the interface. At the reaction-controlled early growth stages, such partial dislocations coexist with the edge dislocations. However, at the diffusion-controlled late growth stages, such partial dislocations are dominant. The observed structures indicate that progression of the Al2O3/MgAl2O4 interface into Al2O3 is accomplished by the glide of partial dislocations accompanied by the exchange of Al3+ and Mg2+ cations. The interface migration may be envisaged as a plane-by-plane zipper-like motion, which repeats along the interface facilitating its propagation. MgAl2O4 grains can adopt two crystallographic orientations with a twinning orientation relationship, and grow by dislocations gliding in opposite directions. Where the oppositely propagating partial dislocations and interface steps meet, interlinked twin boundaries and incoherent Sigma 3 grain boundaries form. The newly grown MgAl2O4 grains compete with each other, leading to a growth selection and successive coarsening of the MgAl2O4 grains. This understanding could help to interpret the interface reaction or phase transformation of a wide range of materials that exhibit a similar h.c.p./c.c.p. transition.

Czech name

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Czech description

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Type

J_imp - Article in a specialist periodical, which is included in the Web of Science database

CEP classification

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OECD FORD branch

10505 - Geology

Project

—

Continuities

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Publication year

2018

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Name of the periodical

Acta Crystallographica. Section A: Foundations and Advances [online]

ISSN

2053-2733

e-ISSN

—

Volume of the periodical

74

Issue of the periodical within the volume

SEP 2018

Country of publishing house

US - UNITED STATES

Number of pages

15

Pages from-to

466-480

UT code for WoS article

000443900900006

EID of the result in the Scopus database

2-s2.0-85052961017