金属颗粒极化中场激发双电层的电荷和电场特征研究

Study on the charge and electric field characteristics of field-induced electric double layer in metal particles polarization

金属颗粒与溶液界面处的场激发双电层是地下含金属介质表现出低频极化现象产生的基础之一,极化过程涉及到外电场、极化电场和扩散场在溶液和颗粒双相介质内的复杂耦合,探究这些物理场在极化中的作用具有重要意义。这里基于Wong极化模型对场激发双电层的极化电荷和不同物理场特征进行详细地分析,首先推导双电层中极化电荷产生的指数衰减电场和偶极子电场,通过计算颗粒和溶液极化电荷密度随频率的变化,明确了极化过程中电荷和不同物理场的变化规律以及对电导率频散的影响,最后利用数值模拟研究颗粒形状对极化电场和电导率频散曲线的影响。结果显示,偶极子电场是引起电导率产生频散现象的主要因素,而指数衰减电场和扩散场是影响溶液极化电荷密度的主要因素,且金属颗粒的形状与极化电场和极化率密切相关。本研究为从微观角度认识金属的激发极化过程和解释电导率频散数据提供了一定的借鉴。

The field-induced electric double layer at the interface between metal particles and the solution is the basis for the low-frequency polarization of underground metal-containing media.The polarization process concerns the complex coupling between the external electrical field,electrical polarization field,and diffusion field in the dual-phase medium of solutions and grains.It is excellent and meaningful to investigate the effects of these fields on IP.In this paper,we analyze the charge and electric field characteristics of the field-induced electric double layer in detail based on Wong's model of electrode polarization.Firstly,we derived the exponentially decaying electric field and the dipole electric field generated by polarized charge in the double layer.Then by calculating the change of the polarized charge density of metal particles and solutions with frequency,the changing trends of charges and different physical fields in the polarization process and the influence on the conductivity dispersion were clarified.Finally,the influence of particle shape change on the polarization electric field and conductivity dispersion curve is studied by numerical simulation.On this basis,the distribution characteristics of current driven by different fields and the effects of these fields on the conductivity dispersion are discussed.The results show that the dipole electric field is found to be the main factor causing conductivity dispersion.In contrast,the exponentially decaying electric field and the diffusion field are the main factors affecting the polarization charge density of the solution,and the polarization electric field and polarizability are closely related to the shape of metal particles.This study serves as a foundation for comprehending IP process from a microscopic viewpoint and explaining the conductivity dispersion and accurate data of metal-bearing media.