Hein L R O, Campos K A, Caltabiano P C R O, Kostov K G
Faculty of Engineering at Guaratinguetá Campus, LAIMat-Materials Imaging Laboratory, UNESP-University Estadual Paulista, Guaratinguetá, São Paulo, Brazil.
Scanning. 2013 May-Jun;35(3):196-204. doi: 10.1002/sca.21048. Epub 2012 Aug 22.
The methodology for fracture analysis of polymeric composites with scanning electron microscopes (SEM) is still under discussion. Many authors prefer to use sputter coating with a conductive material instead of applying low-voltage (LV) or variable-pressure (VP) methods, which preserves the original surfaces. The present work examines the effects of sputter coating with 25 nm of gold on the topography of carbon-epoxy composites fracture surfaces, using an atomic force microscope. Also, the influence of SEM imaging parameters on fractal measurements is evaluated for the VP-SEM and LV-SEM methods. It was observed that topographic measurements were not significantly affected by the gold coating at tested scale. Moreover, changes on SEM setup leads to nonlinear outcome on texture parameters, such as fractal dimension and entropy values. For VP-SEM or LV-SEM, fractal dimension and entropy values did not present any evident relation with image quality parameters, but the resolution must be optimized with imaging setup, accompanied by charge neutralization.
使用扫描电子显微镜（SEM）对聚合物复合材料进行断裂分析的方法仍在讨论中。许多作者更喜欢用导电材料进行溅射镀膜，而不是采用能保留原始表面的低电压（LV）或可变压力（VP）方法。本研究使用原子力显微镜研究了25纳米金溅射镀膜对碳 - 环氧复合材料断裂表面形貌的影响。此外，还评估了VP - SEM和LV - SEM方法中SEM成像参数对分形测量的影响。结果发现，在测试尺度下，形貌测量不受金镀膜的显著影响。此外，SEM设置的变化会导致纹理参数（如分形维数和熵值）产生非线性结果。对于VP - SEM或LV - SEM，分形维数和熵值与图像质量参数没有明显关系，但必须通过成像设置优化分辨率，并进行电荷中和。
