Effect of Simultaneous Addition of Zr and Y on Electrical Characteristics of ZnO Varistors

Abstract

The effect of simultaneously adding Zr and Y to Bi–Mn–Co–Sb–Si–Cr–Ni-added ZnO varistors (having the same composition as a commercial varistor) on the varistor voltage, leakage current, and resistance to electrical degradation were investigated. Varistor voltage increased with increasing amount of Y for addition of 0–2 mol % Zr. On the other hand, the nonlinear coefficient α prior to electrical degradation changed very little on the addition of both Y and Zr. With the addition of approximately 1 mol% Zr, the leakage current decreased with increasing amount of Y added. A ZnO varistor with a varistor voltage of approximately 600 V/m, a low leakage current, and excellent resistance to electrical degradation was fabricated by adding approximately 2 mol% Y and approximately 1 mol% Zr.

Effect of Sb Addition on the Electrical Characteristics of Bi-Based ZnO Varistors Containing Zr and Y

“…The resistance to electrical degradation has been improved by the addition of Zr [6,7]. Simultaneous addition of Y and Zr increases the varistor voltage without deteriorating the resistance to electrical degradation or increasing the leakage current [8]. The present study investigates the effect of adding Sb to Bi-Mn-Co-Si-Cr-Ni-Y-Zr-added ZnO varistors with an aim to minimize the amount of Sb without degradation of the electrical characteristics.…”