1. State Key Laboratory of the Ministry of Education of China for High-efficient Mining and Safety of Metal Mines,University of Science and Technology Bei-jing,Beijing　 100083,China; 2. School of Civil and Resources Engineering,University of Science and Technology Beijing,Beijing　 100083,China; 3. School of Resources and Safety Engineering,China University of Mining and Technology (Beijing),Beijing　 100083,China

为进一步研究煤岩电磁辐射产生机理,通过原子力显微镜研究了不同变质程度煤岩微表面电势及电荷密度等电性参数的变化规律,将煤岩表面微观电性特征研究推进到微纳米尺度。结果表明:煤体表面在细观或宏观统计层面上显弱电性或电中性,但在纳米尺度下对外显示一定的电性特征;计算得到了煤体表面电荷密度,不同煤样的表面电荷密度差异明显,在79. 95～312. 97μC/m2变化;煤的变质程度对表面电性参数存在重要影响:随变质程度的升高,煤表面负电势经历了先缓慢下降又快速升高的变化趋势,表面电荷密度呈现出先减小后增大的"V"型曲线变化。研究煤岩微结构的电性特征,对从微观层面进一步揭示煤岩电磁辐射机理、瓦斯吸附和解吸过程,乃至煤岩物质特性等具有重要意义。

In order to further study the mechanism of the electromagnetic radiation of coal,the atomic force microscopy (AFM) was used to study the distribution rules of electric parameters such as micro-surface potential and charge den- sity of coal samples with different metamorphism grades. This research pushes the study in this field to a micro-nano scale. The results show that the coal surface shows weak electricity at the meso-or macro-level or electrical neutrality, but exhibits certain electrical characteristics at the nanoscale. The surface charge density of coal samples varies from 79. 95 μC / m2 to 312. 97 μC / m2 ,and the difference of which is obvious. The metamorphism grade has an important in- fluence on the electrical parameters of coal surface:with the increase of metamorphism grade,the negative surface po- tential of coal undergoes a slow change first and then rapidly,while the surface charge density shows a “ V” curve change that firstly decreases and then increases. It is of significance to study the micro-electrical characteristics of coal and rock for further revealing the electromagnetic radiation mechanism,gas adsorption and desorption processes,and even the physical properties of coal from the micro level.

国家重点研发计划资助项目(2016YFC0801408)；国家自然科学基金重点资助项目(51774023,51634001)；

HE Xueqiu,SONG Dazhao, LIU Xianfeng, et al. Micro-electrical characteristics of coals with different metamorphic grade[J]. Journal of China Coal Society,2018,43(9):2367-2375.