Nonlinear electrical properties and aging characteristics of (NiO, MgO, Cr2O3)-doped Zn�?�Pr�?�Co�?�R (R = Y, Er) oxide-based varistors

[摘要] The electrical properties and stability of the varistors, which composed of (NiO, MgO, Cr₂O₃)- doped Znâ€�?�Prâ€�?�Coâ€�?�R (Y, Er) oxide-based ceramics, were investigated for different additives. The breakdown voltage of the varistors increased in order of NiO$ightarrow$undoped$ightarrow$MgO$ightarrow$Cr₂O₃: 1200$ightarrow$1551$ightarrow$1691$ightarrow$1959 V/cm for ZPCY system and undoped$ightarrow$NiO$ightarrow$MgO$ightarrow$Cr₂O₃: 1024$ightarrow$1041$ightarrow$1500$ightarrow$1668 V/cm for ZPCE system, respectively. The nonlinear coefficient value increased in order of undoped$ightarrow$NiO$ightarrow$MgO$ightarrow$Cr₂O₃: 21$ightarrow$25$ightarrow$38$ightarrow$50 in ZPCY system and NiO$ightarrow$undoped$ightarrow$MgO$ightarrow$Cr₂O₃: 27$ightarrow$32$ightarrow$35$ightarrow$38 in ZPCE system, respectively. In ZPCY and ZPCE systems, the Cr₂O₃-additives most greatly improved the nonlinear properties. In Cr₂O₃-doped system, ZPCY system exhibited higher nonlinear properties than that of ZPCE system. The stability against d.c. accelerated aging stress was higher in Cr₂O₃-additives than in NiO- and MgO-additives for ZPCY system and was higher in NiO-additives than in MgO- and Cr₂O₃-additives for ZPCE system.

[学科分类] 材料工程

[关键词] ZnO;varistors;microstructure;nonlinear electrical properties;aging characteristics.