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The microstructure, electrical and dielectric properties, and DC-accelerated aging of the ZPCCA (ZnO-Pr 6 O 11 -CoO-Cr 2 O 3 -Al 2 O 3 ) ceramics were investigated with various contents of Er 2 O 3 . The ceramic phases consisted of a bulk phase of ZnO grains, and a minor secondary phase of mixture of Pr 6 O 11 and Er 2 O 3 . The increase of the content of doped Er 2 O 3 increased the densities of sintered pellet from 5.66 to 5.85 g/cm 3 , and decreased the average grain size from 9.6 to 6.3 μm. With the increase of the content of doped Er 2 O 3 , the breakdown field increased from 2390 to 4530 V/cm, and the nonlinear coefficient increased from 28.4 to 39.1. The sample doped with 0.25 mol.% Er 2 O 3 exhibited the strongest electrical stability; variation rates for the breakdown field measured at 1.0 mA/cm 2 , and for the non-ohmic coefficient were −3.4% and −23.8%, respectively, after application of a stress of 0.95 E B /125 °C/24 h. |
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