The effect of processing conditions on varistors prepared from nanocrystalline ZnO

Pillai, Suresh C. and Kelly, John M. and McCormack, Declan E. and O'Brien, Paul and Raghavendra, Ramesh (2003) The effect of processing conditions on varistors prepared from nanocrystalline ZnO. Journal of Materials Chemistry, 13 (10). p. 2586. ISSN 0959-9428

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Abstract

Nanoparticles of ZnO were prepared by the reaction of ethanolic solutions of zinc acetate and oxalic acid followed by drying (80 uC) and calcination (500 uC). Subsequently varistor materials were fabricated from this nanoparticular ZnO via two separate routes:- a) from a ‘‘core shell’’ material using metal salts as additives; b) by using a conventional solid state mixing of metal oxides. Sintering (1050 uC) and subsequent electrical studies were carried out for each of these samples and they were compared with commercial varistor samples prepared under similar conditions. ‘‘Core shell’’ type varistor material showed considerably higher breakdown voltage (Vc ~ 850 ¡ 30 V mm21) as compared to a sample prepared by mixing with metal oxides (Vc ~ 683 ¡ 30 V mm21) or commercial varistor discs (Vc ~ 507 ¡ 30 V mm21). The high breakdown voltage obtained is attributed to the formation of more varistor-active grain boundaries per unit area.

Item Type:	Article
Departments or Groups:	South East Applied Materials Research Centre
Divisions:	School of Engineering
Depositing User:	Ramesh Raghavendra
Date Deposited:	12 Mar 2014 10:19
Last Modified:	22 Aug 2016 10:27
URI:	http://repository-testing.wit.ie/id/eprint/2787

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