La_2O_3掺杂氧化锌压敏阀片压敏电位梯度与显微组织的研究  

Study on Voltage and Microstructure of ZnO Varistor Doped With La_2O_3

作　　者：严群[1] 陈家钊[1] 涂铭旌[1] 

机构地区：[1]四川大学材料科学与工程学院,四川成都610065

出　　处：《中国稀土学报》2003年第z1期130-132,共3页Journal of the Chinese Society of Rare Earths

摘　　要：采用添加微量La2O3的方法,提高氧化锌压敏阀片的电位梯度,使之具有优良的综合性能。同时研究了微量La2O3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结构进行了分析研究,从理论上探讨了La2O3影响氧化锌压敏阀片压敏电位梯度与组织的机理。研究结果表明,在0～0.08%(摩尔分数)成分范围内,随着La2O3含量的增加,氧化锌压敏阀片的压敏电位梯度明显提高;当La2O3含量超过0.08%时,随其含量的增加,氧化锌压敏阀片的压敏电位梯度又呈降低趋势。其原因是La2O3加入到氧化锌压敏阀片中,La主要以固溶的形态分布于ZnO晶内和晶界处,使ZnO晶体的自由电子浓度增大,进而使填隙锌离子Zni的总浓度下降,因此填隙锌离子的传质能力下降,抑制了ZnO晶粒的生长,因而晶粒尺寸随La2O3的添加量下降,压敏电位梯度显著提高。La_2O_3 was used as an additive introduced to ZnO ceramics. The effect of La_2O_3 on voltage and microstructure of ZnO varistor was studied by using electrical property measurements and SEM. The mechanism of the effect was suggested based on theoretical analysis. The results show that the voltage of ZnO varistor increases with the content of La_2O_3 in the range of 0～0.08%(mole fraction). But when the content of La_2O_3 is more than 0.08mol%, the voltage of ZnO varistor decreases with the content increase. The microstructure analysis indicates that the minimal additive lies inside ZnO grain and on the boundary, and it decreases the concentration of interstitial zinc , and then reduces the size of ZnO grain, and as a result, La_2O_3 improve the voltage character of the varistor greatly.

关 键 词：氧化锌压敏阀片 LA2O3 压敏电位梯度 显微组织 

分 类 号：TM283[一般工业技术—材料科学与工程]