Nd_2O_3对氧化锌压敏电阻片压敏电位梯度与组织的影响

Effect of Nd_2O_3 on the Microstructure and Voltage of ZnO Varistor

研究了微量Nd2O3添加剂对氧化锌压敏电阻片的压敏电位梯度的影响,并通过SEM测试手段对其微观组织进行了分析。结果表明,在0～0.04%(mol)成分范围内,随着Nd2O3含量的增加,氧化锌压敏电阻片的压敏电位梯度明显提高,当Nd2O3含量为0.04%(mol)时,氧化锌压敏电阻片的压敏电位梯度达到最大值,约为583.25V/mm,比不含Nd2O3的原始成分的氧化锌压敏电阻片的压敏电位梯度(约354.42V/mm)增加了约65%。其原因是加入到氧化锌压敏电阻片中的Nd2O3主要分布在晶界上,阻碍了ZnO晶界的迁移,从而抑制了ZnO晶粒的长大,使ZnO晶粒更为细小均匀。

The effect of Nd2O3 on voltage and microstructure of ZnO varistor was studied, and the mechanism of the effect was discussed.The results show that Nd2O3 improve the voltage of ZnO varistor in the range of 0～0.04?(mol)%.The voltage of the varistor not containing Nd2O3 is only 354.42?V/mm.In contrast,the voltage of the varistor containing 0.04?(mol)% Nd2O3 reaches 583.25?V/mm, which means the voltage of the varistor increases sharply by about 65%.Electronic scanning microscope observation of fracture surface on the specimen shows that ZnO grains in the varistor containing Nd2O3 are obviously smaller and more uniform than those in the varistor not containing Nd2O3.It is proposed that the minimal additive aggregates at ZnO grain boundary and hinders the movement of grain boundary,which decreases the size of ZnO grain and makes the grain more homogeneous, and then,improves the voltage of varistor greatly.