不同成像原理显微镜在煤微表面形貌表征中的应用

本文分析了光学显微镜、扫描电子显微镜和原子力显微镜的基本成像原理，并通过3种显微镜表征了煤样新鲜断面和抛光表面不同尺度的形貌。研究结果表明，光学显微镜下由于观察范围内煤样新鲜断面各点距离焦点不同使得观察到的图像常出现模糊不清的区域；抛光煤样表面较为平整，成像效果相对较好，且可以定性分析煤的不同组分。扫描电子显微镜扫描倍数可连续放大，且能通过二维图像显示三维结构进而得到更细致的微表面信息，其对抛光表面形貌的观察可以定性分析煤的不同组分。原子力显微镜得到的三维图像较二维图像能够更加直观地展示微表面形貌，微表面粗糙度、高差数值及其统计分布规律可准确得到；原子力显微镜可详细表征纳米级裂隙及其宽度，得到裂隙截面上3处宽度分别为21.63 nm、17.31 nm、8.66 nm。在煤样表面形貌研究中，若将光学显微镜细观表征、扫描电子显微镜微米级扫描和原子力显微镜纳米级探测三者相结合，可精确表达煤样从整体到局部、从毫米级到纳米级的特征，得到较为全面连续、定性定量的信息。

Application of different imaging principles microscopes in characterizing coal microsurface morphology

In this study, the basic imaging principles of optical microscope, scanning electron microscope (SEM) and atomic force microscope (AFM) were analyzed. The fresh section and polished surface morphology with different scales of coal samples were characterized by three kinds of microscopes. The results show that under the optical microscope, blurred areas often appear in the observed images due to the different distances from the focal points to the fresh sections. The surface of polished coal sample is flat, its imaging effect is relatively good, and the different components of coal can be qualitatively analyzed. The images obtained by SEM can be continuously amplified and 3D structure can be displayed by 2D image, then more detailed microsurface information can be observed. The observation of microsurface morphology of polished sample can be used to qualitatively analyze different components of coal. Compared with 2D images, the 3D images obtained by AFM can display the microsurface morphology more intuitively, and the microsurface roughness, height difference and its statistical distribution can be accurately obtained. AFM can characterize the nano crack and its width in detail, and the widths in the three sections of the crack are 21.63 nm, 17.31 nm and 8.66nm, respectively. In the study on surface morphology of coal samples, if the microscopic characterization of optical microscope, micronscale scanning of SEM and nanoscale detection of AFM are combined, the characteristics of samples from whole to local and from millimeter to nanometer can be accurately expressed, and relatively comprehensive and continuous information can be obtained.