Current–voltage characteristics and grain growth of Li2CO3-doped tungsten trioxide ceramics

Wang, Y; Yang, Xinsheng; Li, Z.Q; Yao, K.L.; Liu, Z.L

doi:10.1016/j.materresbull.2004.04.029

Cited by 4 publications

(3 citation statements)

References 16 publications

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“…Wang et al [31] estudaram a adição de Li 2 CO 3 ao WO 3 com respeito a sua influência nas propriedades microestruturais e não lineares. A característica corrente -tensão foi medida em várias temperaturas e todas as curvas mostraram comportamento não ôhmico com o fenômeno de resistência negativa.…”

Section: Resultsunclassified

Varistores à base de WO3 - revisão

Oliveira¹,

Pessoa²,

Brito³

et al. 2016

Matéria (Rio J.)

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RESUMOVaristores são elementos que fazem parte do sistema de transmissão e distribuição de energia elétrica ou de instalações elétricas especiais. Estes dispositivos são amplamente produzidos variando a escala, dependendo de sua aplicação, como dispositivos de baixa voltagem, com poucos grãos, exibindo ruptura de alguns volts, a vários kilovolts como usado em para-raios em rede de distribuição de energia. A física de operação dos varistores tem sido amplamente estudada e tem elementos comuns como barreiras Schottky formado na junção metal/semicondutor. Vários estudos têm sido desenvolvidos a fim de obter cerâmicas varistoras para aplicação em alta e baixa tensão. Dentre esses estudos encontram-se os varistores a base de ZnO, SnO 2 , TiO 2 e mais recentemente os de WO 3 . Diferente das três composições citadas, os a base de WO 3 apresentam comportamento varistor intrínseco devido a presença das fases monoclínica e triclínica. A adição de dopantes doadores e aceitadores de elétrons e o tratamento térmico em diferentes atmosferas também alteram as propiedades não lineares desses sistemas, uma vez que influencia na formação da barreira Schottky. Neste estudo foi realizada uma revisão sobre trabalhos relacionados a nova composição de cerâmica varistora a base de óxido de tungstênio (WO 3 ). Palavras-chave: propriedades elétricas, WO 3 , varistores. _______________________________________________________________________________________ ABSTRACTVaristors are elements that are part of electric power transmission and distribution systems or of special electrical installations. Varistors are manufactured in a wide variety of types, depending on their application, such as low-voltage devices with a layer of a few grains of thickness and low breakdown voltage, to varistors with a breakdown voltage of several kilovolts, such as those used in the lightning arresters of electric power distribution networks. Varistors, whose physical operation has been extensively studied, share common elements such as metal-semiconductor Schottky barrier junctions. Several studies have focused on the development of varistor ceramics for high and low voltage applications, including ZnO, SnO 2 , TiO 2 , and more recently, WO 3 -based ceramics. Unlike the first three compositions, WO 3 -based ceramics present an intrinsic varistor behavior because they contain monoclinic and triclinic phases. The addition of electron donor and acceptor dopants and heat treatments in different atmospheres also alter the non-linear properties of these systems, since they affect the formation of the Schottky barrier. This paper offers a review of the literature on the new varistor ceramic composition based on tungsten oxide (WO 3 ). Keywords: electrical properties, WO 3 , varistors. _______________________________________________________________________________________ INTRODUÇÃOVaristores, resistores não ôhmicos ou ainda resistores variáveis, são elementos que fazem parte do sistema de transmissão e distribuição de energia elétrica ou de instalações elétricas espec...

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Section: Resultsunclassified

Varistores à base de WO3 - revisão

Oliveira¹,

Pessoa²,

Brito³

et al. 2016

Matéria (Rio J.)

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“…The above results indicate that the nonlinear electrical behavior of polymer/ manganese oxide composite is an intrinsic property, not caused by Joule heating effect. 19,20…”

Section: Resultsmentioning

confidence: 99%

Composite varistors based on epoxy resin/La_0.8Sr_0.2MnO₃

Yang

Kim

Yang

et al. 2013

Journal of Composite Materials

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Polymer/perovskite manganese oxide (epoxy resin/La0.8Sr0.2MnO3) composites are prepared using bonded method. There is no reaction between La0.8Sr0.2MnO3 and the polymer. The nonlinear current–voltage property is significantly affected by the content of polymer. The resistivity and nonlinear coefficient increase with the increase of polymer content. The resistivity of the composites is 5–9 orders of magnitude higher than that of the sintering ceramics. The nonlinear electrical behavior is an intrinsic property. Compared with conventional sintered ceramic varistors, the polymer/manganese oxide composite varistors have greater nonlinear coefficient above 45.

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“…At the same time, varistors based on other ceramic systems are also under investigation and development because of the need for even better properties, such as low voltage and high dielectric constants. Since Makarov and Trontelj [1] found that Na 2 CO 3 -and MnO 2 -doped WO 3 ceramics exhibited non-linear current-voltage characteristics, some investigations [2][3][4][5][6] have been done to further clarify the physical mechanism of microcosmic electrical transport and to improve its electrical properties.…”

Section: Introductionmentioning

confidence: 99%

Improved Stability of Mn-Doped WO3 Varistor via Doping Cr2O3

Liu

Zhao

Zhu

et al. 2007

KEM

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In this paper, the effect of Cr2O3 addition on the electrical properties and microstructures of WO3-MnO2 ceramics was studied. The samples were fabricated by the conventional solid phase reaction techniques. The current-voltage curves and impedance spectra of sintered samples were measured at room temperature. The samples without Cr2O3 doping exhibit the max nonlinear coefficient α above 8 in current region from 1mA to 10mA and an unstable characteristic of current-voltage curve for repeat measuring cycle, while the samples doped with Cr2O3 display lower nonlinearity with α about 5 and an improved stability of current-voltage curve at the same conditions. The impedance measurements indicate that the influence on electrical properties comes from grain boundary as well as grain. SEM shows the doping of Cr2O3 into WO3-MnO2 ceramics suppresses obviously the growth of WO3, and XRD analysis reveals the coexistence of WO3 phases with some manganese tungstates and chromium tungstates. The problems related to electrical transporting mechanism were discussed simply.

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Current–voltage characteristics and grain growth of Li2CO3-doped tungsten trioxide ceramics

Cited by 4 publications

References 16 publications

Varistores à base de WO3 - revisão

Varistores à base de WO3 - revisão

Composite varistors based on epoxy resin/La_0.8Sr_0.2MnO₃

Improved Stability of Mn-Doped WO<sub>3</sub> Varistor via Doping Cr<sub>2</sub>O<sub>3</sub>

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Current–voltage characteristics and grain growth of Li2CO3-doped tungsten trioxide ceramics

Cited by 4 publications

References 16 publications

Varistores à base de WO3 - revisão

Varistores à base de WO3 - revisão

Composite varistors based on epoxy resin/La0.8Sr0.2MnO3

Improved Stability of Mn-Doped WO<sub>3</sub> Varistor via Doping Cr<sub>2</sub>O<sub>3</sub>

Contact Info

Product

Resources

About

Composite varistors based on epoxy resin/La_0.8Sr_0.2MnO₃