分析了添加剂离子半径(Ri)对氧化锌(ZnO)压敏电阻最大非线性系数(αmax)的影响。通过数据分析和曲线拟合得到αmax与R i之间的函数关系,同时发现了R i和锌离子(Zn2+)半径之间的相对偏差(△Rrel)对αmax值的影响规律。结果表明:αmax与Ri之间满足特定的函数关系,通过该函数关系计算得到的αmax值能够和相关文献中报道的实际非线性系数(αrea)吻合;压敏电阻的αmax值随着?Rrel的增大而增大,当?R rel大于30%时,其增大程度开始变缓,此时ZnO压敏电阻的αmax值大于64。对于R i不同而?Rrel相同的2种添加剂离子,Ri大于Zn2+半径的添加剂掺杂的ZnO压敏电阻的αmax值较大。从固溶体的形成机理和能量最低原理方面解释了以上现象。
The effect of additive ionic radius (Ri) on the maximum nonlinear coefficient (αmax) of ZnO varistors was investigated. The functional relation between areax and Ri is obtained. In addition, the influences of relative deviation △Rrel of Ri and the zinc ionic radius (R) on the value of amax were also discussed. The results indicate that the relation between αmax and Ri can be described, and the calculated values of amax coincide with the real nonlinear coefficient (area) obtained in some previous work. The value of amax increases with the increase of the relative deviation △Rrel, and αmax approaches a saturation value when the values of ARreI are greater than 30%, beyond which αmax is 〉 64. For the additive ions with different Ri values and the same △Rrel value, the value of amax can be enhanced when Ri is greater than that of zinc ionic. The results obtained can be explained via the formation mechanism of the solid solution and the principle of minimum energy.