氧化锌压敏电阻的烧结行为

为了研究ZnO压敏电阻组成中非化学配比氧化物对ZnO压敏电阻导电性能的影响,采用在不同氧分压条件下烧结样品以研究其烧结行为。结果表明：ZnO晶粒的电导率对数与氧分压对数成线性关系;斜率为-1/4;间隙Zn原子以一价电离Zni形式存在。由于CoO,MnO和NiO阳离子空位氧化物多偏析于晶界,晶界处氧的增加有利于降低压敏电阻漏电流,烧结时间从2h延长到8h,漏电流从5μA/cm^2降到3.6μA/cm^2。波谱分析表明：掺杂氧化物在晶界处都有偏析,ZnO晶粒中掺杂原子混溶比例不完全与掺杂阳离子半径相关。

SINTERED BEHAVIOR OF ZINC OXIDE VARISTOR

In order to study the influence of nonstoichiometry metal oxide on ZnO varistor, the ZnO ceramics were sintered under different oxygen partial pressure. The results show that the logarithm of conductivity of pure ZnO ceramic depends on linearly logarithm of oxygen pressure with slope of -1/4 and the interstitial Zn atom exists in the form of Zn~*_i. The oxygen atom at crystal boundary helps to decrease the leakage current of the ZnO varistor, for some cation-vacancy oxides, such as CoO, MnO and NiO aggregated there. By increasing sintering time from 2 h to 8 h, the leakage current drops from 5 A/cm~(2) to (3.6 A/cm~(2)). WDS (wave dispersive spectroscopy) test shows that all doping oxides tend to aggregate at crystal boundary and the quantity of remanent dopants in ZnO crystal is not completely correlated with its ionic radii.