Saltas Vassilios, Pentari Despoina, Vallianatos Filippos
Institute of Physics of the Earth's Interior and Geohazards, Hellenic Mediterranean University Research Center, 73100 Chania, Greece.
Laboratory of Inorganic and Organic Geochemistry and Organic Petrography, Department of Mineral Resources Engineering, Technical University of Crete, 73100 Chania, Greece.
Materials (Basel). 2020 Aug 9;13(16):3513. doi: 10.3390/ma13163513.
The unique physicochemical, electrical, mechanical, and thermal properties of micas make them suitable for a wide range of industrial applications, and thus, the interest for these kind of hydrous aluminosilicate minerals is still persistent, not only from a practical but also from a scientific point of view. In the present work, complex impedance spectroscopy measurements were carried out in muscovite and biotite micas, perpendicular to their cleavage planes, over a broad range of frequencies (10 Hz to 10 Hz) and temperatures (473-1173 K) that have not been measured so far. Different formalisms of data representation were used, namely, Cole-Cole plots of complex impedance, complex electrical conductivity and electric modulus to analyze the electrical behavior of micas and the electrical signatures of the dehydration/dehydroxylation processes. Our results suggest that ac-conductivity is affected by the structural hydroxyls and the different concentrations of transition metals (Fe, Ti and Mg) in biotite and muscovite micas. The estimated activation energies, i.e., 0.33-0.83 eV for biotite and 0.69-1.92 eV for muscovite, were attributed to proton and small polaron conduction, due to the bound water and different oxidation states of Fe.
云母独特的物理化学、电学、力学和热学性质使其适用于广泛的工业应用，因此，不仅从实际角度，而且从科学角度来看，对这类含水铝硅酸盐矿物的兴趣依然持续存在。在本工作中，在白云母和黑云母垂直于其解理面的方向上，于尚未测量过的宽频率范围（10 Hz至10 Hz）和温度范围（473 - 1173 K）内进行了复阻抗谱测量。使用了不同的数据表示形式，即复阻抗、复电导率和电模量的Cole - Cole图，以分析云母的电学行为以及脱水/脱羟基过程的电特征。我们的结果表明，交流电导率受结构羟基以及黑云母和白云母中不同浓度的过渡金属（Fe、Ti和Mg）的影响。估计的活化能，即黑云母为0.33 - 0.83 eV，白云母为0.69 - 1.92 eV，归因于质子和小极化子传导，这是由于结合水和Fe的不同氧化态所致。
