氧化锌压敏电阻综合性能的多元掺杂综合调控  

Comprehensive Performances of ZnO Varistors Tailored by Multi-elements Doping

作　　者：孟鹏飞 胡军 邬锦波 何金良 

机构地区：[1]清华大学电机工程与应用电子技术系电力系统及发电设备控制和仿真国家重点实验室

出　　处：《高电压技术》2018年第1期241-247,共7页High Voltage Engineering

基　　金：国家电网公司科技项目(SGTYHT/15-JS-191);国家自然科学基金(50737001)~~

摘　　要：氧化锌压敏电阻是避雷器的核心元件。研究了多元素掺杂的稀土掺杂的氧化锌压敏电阻的电气性能，选用了铝、镓、钇元素掺杂来综合提高氧化锌压敏电阻的综合电气性能。随着镓元素的引入，稀土钇掺杂的氧化锌压敏电阻的泄漏电流得到了明显的抑制。Ga3＋占据了氧化锌晶界层上的空位，从而提高了晶界的势垒高度，因此，压敏电阻的泄漏电流得到了有效的抑制。Y203主要位于氧化锌晶粒的周围抑制氧化锌晶粒的生长，从而提高了压敏电阻的电压梯度。Al3＋固溶到了氧化锌晶粒中降低了晶粒的阻抗，因此可以有效降低压敏电阻在通过大电流时的残压比。当氧化镓、硝酸钇、硝酸铝的掺杂摩尔分数分别为0．5、0．9、0．2时可以获取最佳的电气性能，此时压敏电阻的非线性系数为83，残压比1．56，泄漏电流密度为1．44gA／cm2，电压梯度达到479V／mm。此多元素掺杂研究有助于提高氧化锌避雷器的保护性能，实现深度限制电力系统，特别是特高压系统的过电压。ZnO varistor is the core element of surge arresters. We investigated the electrical characteristics of rare earth doped ZnO varistor ceramics. Multiple donor dopants （Al3＋, Ga3＋, and Y3＋） were employed to improve the comprehensive performances of ZnO varistor ceramics. The leakage current of rare earth doped ZnO varistor ceramics decreased noticea- bly with Ga2O3 dopants. The Ga3＋ dopant occupies the defect sites of grain boundaries and increases the barrier potential of ZnO varistor ceramics, so the leakage current is effectively inhibited. Y2O3 is primarily located around the grains, which restrains ZnO grain growth, increasing the voltage gradient. The Al3＋ enters the lattices of ZnO grains, decreasing the grain resistance; thus, the residual voltage ratio can be controlled at low levels under a high impulse current. These multiple donor dopants can aid in engineering high-quality ZnO varistors. When being doped with 0,5 mole fraction Ga2O3, 0.9 mole fraction Y（NO3）3, and 0.2 mole fraction Al（NO3）3, the sintered varistors showed optimal electrical prop- erties with a nonlinear coefficient of 83, residual voltage ratio of 1.56, leakage current of 1.44 μA/cm2, and voltage gradient of 479 V/mm. This study helps to improve the protection effect of surge arresters, and realizes deeply suppress- ing the overvoltage of power systems, especially the UHV systems.

关 键 词：氧化锌压敏电阻 电气性能 微观结构 多元掺杂:晶界层 

分 类 号：TM54[电气工程—电器]