Paper Title:

Chemical Synthesis by Pechini Method for Obtation of ZnO Varistors

Periodical Materials Science Forum (Volumes 498 - 499)
Main Theme Advanced Powder Technology IV
Edited by Lucio Salgado and Francisco Ambrozio Filho
Pages 299-304
DOI 10.4028/www.scientific.net/MSF.498-499.299
Citation P.C. Ribeiro et al., 2005, Materials Science Forum, 498-499, 299
Online since November 2005
Authors P.C. Ribeiro, E.G. da Costa, Lucianna Gama, Ana Cristina Figueiredo de Melo Costa, Ruth Herta Goldsmith Aliaga Kiminami
Keywords Electrical Properties, Micro-Structural Properties, Pechini Method, ZnO Varistor
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The zinc oxide varistors are ceramic semiconductor devices doped with some metallic oxides such as: bismuth, nickel, manganese, cobalt, and others. The aim of this work is to characterize the varistors, obtained by the Pechini’s method, regarding their microstructure and electrical features. By using chemical synthesis, it has been produced ceramic powders. The powders have been compacted in the form of pellets and sintered at 1200°C/1h. The samples have been characterized by measurements of J x E, XRD and by SEM. The results show that the powders obtained through Pechini’s synthesis method and calcined at 700°C/1h have a particle size of less than 100 nm. The resulting microstructures show heterogeneous morphologies in a shape of pins and presence of inter and intragrain porosity. The electrically characterized results show that the produced varistors present a nonlinearity coefficient of 21 and breakdown voltage of 1590 V/cm.

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