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On the relationship between modification of Bi2O3 by Sb and type of grain boundaries in ZnO-based varistors

2021; Elsevier BV; Volume: 122; Linguagem: Inglês

10.1016/j.engfailanal.2021.105251

1873-1961

J. Warycha, Witold Mielcarek, Grzegorz Lesiuk,

Transition Metal Oxide Nanomaterials

The possibility of eliminating of electrically inactive areas from varistor body with maintaining varistor electrical parameters can be achieved by modifying Bi2O3 in such a way that a Bi-rich layer which surrounds the grains of ZnO is as thin as possible and by minimizing of the amount of additives so as not to form electrically inactive areas in varistor. It has been proven that modification of Bi2O3 with small quantities of other MeO results in significant changes in the varistor structure, thereby gaining the uniform distribution of the intergranular phase. The work contains the results on which Sb2O3 were added in an amount of 15 mol%. After mixing with Bi2O3 they were sintered and shivered. Modified Bi2O3 was added to the varistor bulk in quantities of 1.0, 0.3, 0.2 and 0.1 mol% to study the varistor properties. The best results were obtained for the varistor doped with 0.3 mol% Bi2O3 modified by Sb, which has the best compatibility with the mathematically model calculated by statistical methods describing 100% of conductive grain boundaries. The obtained results of the varistors microstructure modification led additionally to reduce amounts of additives for about 30% and thus to lower at about 10% of production costs.