Ramirez, M. A. [UNESP]Fernandez, J. F.De la Rubia, M.de Frutos, J.Bueno, Paulo Roberto [UNESP]Longo, Elson [UNESP]Varela, José Arana [UNESP]2014-05-202014-05-202009-01-01Journal of Materials Science-materials In Electronics. Dordrecht: Springer, v. 20, n. 1, p. 49-54, 2009.0957-4522http://hdl.handle.net/11449/9412This work deals with the electrical properties of SnO2-based varistor systems with different area-volume (A/V) ratio of the green compact. The influence of A/V ratio specially on microstructural homogeneity and different diameter-thickness (D/t) ratio of sintered compact mainly as a requisite to the existence of non-Ohmic properties is evaluated. The results evidence that, contrary of what is generally observed for ZnO-based varistor system, in the SnO2-based system, the A/V ratio of the green compacts does not influence the non-Ohmic properties, i.e. the homogeneity of the microstructure and the composition after sintering is conserved independently of the A/V ratio employed in the green compacts. Such independence was specifically observed by performing non-Ohmic measurement after cutting the sintered blocks in different slices and observing that the current-voltage curve of the slices are very similar for different A/V ratio of the green compacts before sintering. The observed behavior has its origin on the fact that A/V ratio does not affect the microstructure development during sintering due to the minimal CoO losses by vaporization for SnO2-based system, i.e. the stability of the dopant oxides is high when compared with that used in commercial ZnO center dot A Bi2O3-based varistors in which, for instance, Bi2O3 volatilizes critically. on the other hand, it was found a critical value of A/V = 5.0 cm(-1) for the ceramic blocks to effectively served as varistor, below this ratio the ceramics were highly resistive because of a high number of effective barriers 85% which is higher than normally found for ZnO-based systems (35%).49-54engArtigo10.1007/s10854-008-9602-8WOS:000261970500009Acesso restrito04770459067332540000-0003-2827-0208