da Silva, RT, Morbec, JM, Rahman, G and de Carvalho, HB (2022) A comprehensive study on the processing of Co:ZnO nanostructured ceramics: Defect chemistry engineering and grain growth kinetics. Journal of Materials Science & Technology. ISSN 1005-0302

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Abstract

In this report, we present a systematic study on the preparation of Co:ZnO ceramics via a standard solid-state route from different Co precursors (Co3O4, CoO, and metallic Co) and atmospheres (O2 and Ar). Particular emphasis is given to defect chemistry engineering and the sintering growth kinetics. First-principles calculations based on density functional theory are employed to determine the formation energy of the main point defects in ZnO and Co:ZnO systems. Based on the theoretical results, a set of chemical reactions is proposed. Detailed microstructural characterization is also performed to determine the degree of Co incorporation into the ZnO lattice. The samples prepared in Ar atmosphere and metallic Co present the highest Co solubility limit (lower apparent Co incorporation activation energy) due to the incongruent ZnO decomposition. Determination of the parameters of the sintering growth kinetics reveals that Co3O4 is the best sintering additive to achieve larger grain sizes, and possible higher densities, in both sintering atmospheres, while metallic Co is the best to achieve the smallest grain size with higher Co concentration and homogeneous spatial distribution for a subsequent reduction of dimensionality. The results show that the sintering in O2 effectively promotes zinc vacancies in the ZnO structure, while the sintering in Ar promotes zinc interstitial defects. Our findings contribute to understanding the preparation of Co-doped ZnO ceramics and the sintering growth kinetics, which may improve the state of the art in processing the material at both bulk and nanometric scales.

Item Type: Article
Additional Information: The final version of this article and all relevant information related to it, including copyrights, can be found on the publisher website.
Subjects: Q Science > Q Science (General)
Q Science > QD Chemistry
Q Science > QD Chemistry > QD415 Biochemistry
Divisions: Faculty of Natural Sciences > School of Chemical and Physical Sciences
Depositing User: Symplectic
Date Deposited: 12 Oct 2022 08:26
Last Modified: 12 Oct 2022 08:26
URI: https://eprints.keele.ac.uk/id/eprint/11528

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