| Zn-Pr-Co-Cr-Dy 산화물계 바리스터 세라믹스의 전기적 안정성 |
| 남춘우, 박종아, 김명준, 류정선1 |
동의대학교 전기공학과
1동의대학교 전자세라믹스센터 |
| Electrical Stability of Zn-Pr-Co-Cr-Dy Oxides-based Varistor Ceramics |
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| ABSTRACT |
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The electrical stability of the varistor ceramics composed of Zn-Pr-Co-Cr-Dy oxides-based varistors was investigated at 0.0∼2.0 mol% Dy$_2$O$_3$ content under DC accelerated aging stress. The ceramic density was increased up to 0.5 mol% Dy$_2$O$_3$ whereas further addition of Dy$_2$O$_3$ decreased sintered ceramic density. The density sailently affected the stability due to the variation of conduction path. The nonlinearity of varistor ceramics was greatly improved above 45 in the nonlinear exponent and below nearly 1.0 ${mu}$A by incorporating Dy$_2$O$_3$. Under 0.95 V$_$1mA/150$^{circ}C$/24 h stress state, the varistor ceramics doped with 0.5 mol% Dy$_2$O$_3$ exhibited the highest electrical stability, in which the variation rates of varistor voltage, nonlinear exponent, and leakage current were -0.9%, -14.4%, and +483.3%, respectively. The variation rates of relative permittivity and dissipation factor were +7.1% and +315.4%, respectively. The varistors with further addition of Dy$_2$O$_3$ exhibited very unstable state resulting in the thermal runaway due to low density. |
| Key words:
Varistor ceramics, Zn-Pr-Co-Cr-Dy oxides-based varistors, Nonlinearity, DC accelerated aging stress, Stability |
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