MnO_2的粉体阻抗谱测量

Measurement of A. C. Impedance for MnO_2 Powders

用交流阻抗方法对粉末状和压片的电解MnO_2(EMD)和天然锰矿进行测量。其电阻率有下列顺序:ρ日本锰粉<ρ湘潭锰粉<ρ松桃锰粉。电阻率与外加压力有关。经不同温度烘烤后,阻抗谱有明显变化。讨论了噪声对高频测量的影响。用最小二乘法来模拟压片状阻抗谱。说明它是由晶粒、晶界和颗粒间界三部分阻抗组成。探讨了它与MnO_2电化学活性的关系。

The A. C. impedance method was used to measure the impedance of powder and pressed pellets for electrolytic MnO2 (EMD) and some natural manganese dioxide minerals. They showed an increasing resistivities in order, ρ Japan<ρ Xiantan<ρ Tho-ngtao. The resistivities were dependent on the exponential power of pressure. After the rmal treatment at diffrent temperatures, the impedance spectra obviously changed. The influence of noise on the measured impedance in the high frequencyranges was discussed. It was established using the least square method that the pressed pellet impedance spectra were composed of three parts, grain, grain boundary and inter-particles. The relation between their resistivities and electrochemical activities were also studied.