Characterization of ZnO-degraded varistors used in high-tension devices

dc.contributorUniversidade Estadual Paulista (UNESP)
dc.creatorRamirez, M. A.
dc.creatorSimoes, A. Z.
dc.creatorMarquez, M. A.
dc.creatorManiette, Y.
dc.creatorCavalheiro, A. A.
dc.creatorVarela, José Arana
dc.date2014-05-20T15:22:53Z
dc.date2016-10-25T17:56:41Z
dc.date2014-05-20T15:22:53Z
dc.date2016-10-25T17:56:41Z
dc.date2007-06-05
dc.date.accessioned2017-04-05T23:39:06Z
dc.date.available2017-04-05T23:39:06Z
dc.identifierMaterials Research Bulletin. Oxford: Pergamon-Elsevier B.V., v. 42, n. 6, p. 1159-1168, 2007.
dc.identifier0025-5408
dc.identifierhttp://hdl.handle.net/11449/33790
dc.identifierhttp://acervodigital.unesp.br/handle/11449/33790
dc.identifier10.1016/j.materresbull.2006.09.001
dc.identifierWOS:000246273600022
dc.identifierhttp://dx.doi.org/10.1016/j.materresbull.2006.09.001
dc.identifier.urihttp://repositorioslatinoamericanos.uchile.cl/handle/2250/877830
dc.descriptionThe effects of the degradation process on the structural, microstructural and electrical properties of ZnO-based varistors were analyzed. Rietveld refinement showed that the BiO2-x phase is affected by the degradation process. Besides the changes in the spinel phase, the degradation process also affects the lattice microstrain in the ZnO phase. Scanning electron microscopy analysis showed electrode-melting failure, while wavelength dispersive X-ray spectroscopy qualitative analysis showed deficiency of oxygen species at the grain boundaries in the degraded samples. Atomic force microscopy using electrostatic mode force illustrated a decrease in the charge density at the grain boundaries of the degraded sample. Transmission electron microscopy showed submicrometric spinel grains embedded in a ZnO matrix, but their average grain size is smaller in the degraded sample than in the standard one. Long pulses appeared to be more harmful for the varistors' properties than short ones, causing higher leakage current values. The electrical characteristics of the degraded sample are partially restored after heat treatment in an oxygen-rich atmosphere. (C) 2006 Elsevier Ltd. All rights reserved.
dc.languageeng
dc.publisherElsevier B.V.
dc.relationMaterials Research Bulletin
dc.rightsinfo:eu-repo/semantics/closedAccess
dc.subjectceramics
dc.subjectelectron microscopy
dc.subjectelectrical properties
dc.titleCharacterization of ZnO-degraded varistors used in high-tension devices
dc.typeOtro


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