• 한국전기전자재료학회논문지
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• 제13권3호
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• pp.206-213
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• 2000

The microstructure and electrical properties of Pr$_{6}$/O sub 11/-Based ZnO varistors with Nd$_2$O$_3$ was doped in the range of 0.0 to 2.0 mol% were investigated. Most of the added Nd$_2$O$_3$were segregated at the nodal points and grain boundaries and were found to form the Nd-rich phase. In addition the bulk intergranular layer at the grain boundaries and nodal points was consisted of Nd-rich phase and Pr-rich phase. the average grain size was decreased in the range of 7.8 to 5.6${\mu}{\textrm}{m}$ with increasing Nd$_{2}$/O sub 3/ additive content. The nonlinearity of ZnO varistors sintered at 130$0^{\circ}C$ was much more excellent than that at 135$0^{\circ}C$ ZnO varistors doped with 1.0mol% Nd$_{2}$/O sub 3/ exhibited the best nonlinearity. which is 65.2 in the nonlinear exponent and 4.5$\mu$A in the leakage current. Consequently. it is estimated that Pr$_{6}$/O sub 11/ -based ZnO varistors doped with 1.0 mol% Nd$_{2}$/O sub 3/ are to be sufficiently used as basic composition to fabricate good varistors in the future.ure.

• 한국전기전자재료학회논문지
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• 제13권5호
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• pp.402-410
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• 2000

The electrical properties and stability of Pr$_{6}$/O$_{11}$-based ZnO wvaristors consisting of ZnO-Pr$_{6}$/O$_{11}$-CoO-Dy$_{2}$/O$_{3}$ based ceramics were investigated in the Dy$_{2}$/O$_{3}$ additive content range o 0.0 to 2.0 mol%. The density was nearly constant 5.62 g/cm$^3$corresponding to 97% of theoretical density as Dy$_{2}$/O$_{3}$ additive content increases up to 0.5 mol%. However the density decreased as Dy$_{2}$/O sub 3/ additive content is further additive content. Pr$_{6}$/O$_{11}$-based ZnO varistors doped with 0.5mol% Dy$_{2}$/O$_{3}$ exhibited a good nonlinearity, which is 37.76 in the nonlinear exponent and 5.36 $mutextrm{A}$ in the leakage current. And they exhibited very stress (0.80 V$_{1mA}$/9$0^{\circ}C$/12h)+(0.85 V$_{1mA}$/115$^{\circ}C$/12h)+(0.95 V$_{1mA}$/1$25^{\circ}C$/12h). Consequently it was estimated that ZnO-0.5 mol% Pr$_{6}$/O$_{11}$-1.0 mol% CoO-0.5 mol% Dy$_{2}$/O$_{3}$ based ceramics will be sufficiently used as a basic composition to develop the advanced Pr$_{6}$/O$_{11}$-based ZnO varistors in the future.he future.uture.he future.