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Descripción
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| Times Cited: 2 References: 23 Citation Map Abstract: This 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%). | |
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Internacional
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Si |
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JCR del ISI
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No |
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Título de la revista
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Journal of materials science. Materials in electronics |
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ISSN
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0957-4522 |
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Factor de impacto JCR
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0 |
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Información de impacto
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Volumen
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20 |
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DOI
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10.1007/s10854-008-9602-8 |
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Número de revista
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1 |
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Desde la página
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49 |
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Hasta la página
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54 |
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Mes
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ENERO |
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Ranking
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