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Journal articles
Construction of master sintering curves to understand the effect of Na addition on ZnO-based varistors
Abstract : This work describes the effect of a small sodium addition on the densification of Bi2 O3 -based ZnO varistors. The characterisation was performed using both the master sintering curve tool and the analyses of structural and microstructural characteristics of the materials. It was found that sodium-free varistor material exhibited very low activation energy for densification (149.2kJ/mol). This was explained by the liquid phase promoting diffusion through the enhanced reaction between ZnO and Bi2 O3 . For sodium-doped material, the calculated activation energy was much higher (292.5kJ/mol) and was very close to the one obtained for pure ZnO, which is often related to the grain boundary solid-state diffusion. It was shown that a small sodium addition prevented Bi2 O3 from satisfactorily reacting with ZnO. Finally, a mechanism was proposed to explain how a slight sodium amount altered the reactivity between Bi2 O3 and the ZnO matrix, resulting in some major changes in the final microstructures. © 2015 Elsevier Ltd.
https://hal-normandie-univ.archives-ouvertes.fr/hal-02184097
Contributor : Elisabeth van T Hof <>
Submitted on : Monday, July 15, 2019 - 6:03:49 PM
Last modification on : Friday, February 28, 2020 - 1:26:14 PM
Contributor : Elisabeth van T Hof <>
Submitted on : Monday, July 15, 2019 - 6:03:49 PM
Last modification on : Friday, February 28, 2020 - 1:26:14 PM
