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The effect of aluminium additive on the electrical properties of ZnO varistors

Gubański A., Mielcarek W., Prociów K., Warycha J., Wróbel J. M.

Materials Science Poland

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2009

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Vol. 27, No. 4/2

1207--1218

EN

Reliable and undisturbed operation of electric and electronic circuits is mainly achieved through the use of appropriate overload protection elements such as overvoltage surge arrestors. The stability of metal oxide varistors which are used insures that the circuits are adequately protected. The point of adding the varistor material with aluminium is the extension of the nonlinearity of I-V characteristic in high current region. In this work, both the aluminium doping for ZnO varistors, and the effect of this doping on the ageing processes in varistors were investigated. The current trend towards the production of better and more robust surge arrestors which utilize mainly ZnO varistors motivated these studies. The fundamental technological impediments include the repeatability of manufactured varistors and their susceptibility to ageing factors such as current shocks, elevated operation temperature and the extended effect of the operation potential. Improving the varistor imperviousness to ageing continues to be an imperative but, as yet, unsolved problem.

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The effect of aluminium additive on the electrical properties of zno varistors.

Gubański A., Mielcarek W., Prociow K., Warycha J.

Prace Naukowe Instytutu Podstaw Elektrotechniki i Elektrotechnologii Politechniki Wrocławskiej. Konferencje

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2007

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Vol. 46, nr 19

131-136

EN

Reliable and undisturbed operation of electric and electronic circuits is mainly achieved through the use of appropriate overload protection elements such as overvoltage surge arrestors. The stability of the metal oxide varistors which are used insures that the circuits are adequately protected. The point of adding the varistor material with aluminium is the extension of the I_V characteristic's nonlinearity in high-current region [1]. In this work, both the viability of aluminum doping for ZnO varistors, and the effect of this doping on the ageing processes in varistors were investigated. The current trend is towards the production of better and more robust surge arrestors which utilize mainly ZnO varistors, and it was this trend which motivated these studies. The fundamental technological impediments include the repeatability of manufactured varistors and their susceptibility to ageing factors, such as current shocks, elevated operation temperature and the extended effect of the operation potential. Improving the varistors' imperviousness to ageing continues to be an imperative but, as yet, unsolved problem.

3

Wpływ domieszki glinu na właściwości elektryczne warystorów ZnO.

Gubiński A., Mielcarek W., Prociów K.

Prace Naukowe Instytutu Podstaw Elektrotechniki i Elektrotechnologii Politechniki Wrocławskiej. Konferencje

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2006

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Vol. 44, nr 18

327-333

PL

Niezawodna oraz niezakłócona praca urządzeń elektroenergetycznych i elektronicznych jest głównie osiągana poprzez zastosowanie odpowiednich elementów ochrony przepięciowej takich jak ograniczniki. Warunkiem dobrej ochrony jest stabilność zawartych w nich warystorów tlenkowych.. Dodatek glinu jest stosowany w celu zwiększenia nieliniowości charakterystyki U-I warystora w zakresie wysokich prądów [1], Zbadano wpływ domieszkowania glinem na charakterystyki U-I warystorów z tlenku cynku, oraz wpływ tej domieszki na procesy starzenia warystorów. Zasadność badań wynika z dążenia do wytwarzania coraz lepszych i trwalszych zabezpieczeń przeciwprzepięciowych, których głównymi elementami składowymi są w obecnych czasach warystory z tlenku cynku. Zasadniczym problemem jest powtarzalność parametrów wytwarzanych warystorów oraz ich podatność na czynniki degradujące, do których należą udary prądowe, podwyższona temperatura i długotrwałe działanie napięcia pracy. Poprawa odporności warystorów na starzenie jest istotnym i ciągle nierozstrzygniętym problemem.

EN

ZnO varistors exhibiting non-linear resistance are widely applied as suppressor components to limiters of voltages. The varistor operating voltage is very close to working voltage of the protected device. Therefore varistors have to characterize long-term stability and their electricar parameters must be maintained for a long time during service. Although the roles of the typical individual additives like Sb, Co, Cr, Mn and Ni in imparting the non-linear property to ZnO ceramics are well recognized, the role of Al. additive still raise questions. The effect of Al on I-V characteristics od ZnO ceramics and varistors' susceptibility for actions of ageing agents like surge currents, elevated temperatures and long term service has been studied.