中文摘要：

为研究废弃电路板的破坏机制，采用扫描电镜对6个典型的废弃电路板材料断口进行形貌分析。电路板外观形貌具有白相似性，表现出分形的特征。基于分形理论和计算机图像处理技术，编制计算材料断口形貌计盒分形维数的MATLAB程序。MATLAB计算程序拟合直线的线性度很好，表明电路板材料断口的分形行为显著。6个断口的分形维数不同，表明它们的复杂程度和粗糙度不同。断口3为集成电路中树脂的断口，材料断裂后有一定的凹凸面，并且有缺陷和微孔，故表面形貌最为复杂，分形维数最大，为1．415。断口2、断口5和断口6外观形貌较规则，分形维数较小。断口1和断口4均为硬塑料断口形貌，有河流状花纹，断口1和断口4的表面粗糙度介于断口3与断口2、断口5和断口6之间。通过分形维数的计算可知6个断口纹理的粗糙和复杂程度从大小依次为断口3，1，4，5，2和6，这与人眼观察到的结果基本一致，也进一步说明电路板及其元器件在破坏后，其断口形貌具有分形的特征。

英文摘要：

In order to study the rupture mechanism of waste printed circuit boards （PCB）, an S-3000N scanning electron microscope was adopted to analyze fracture morphology of PCB. The surface topography of PCB manifests selfsimilarity, which shows that the material fracture possesses fractal characteristics. Based on the fractal theory and computer images analysis technique, a MATLAB program which computes box fractal dimension of material fracture was designed. The linear degree of fit beeline of MATLAB program is high, which shows fractal behavior of PCB＇s fracture is obvious. The different fractal dimensions of 6 fractures show that complexity and roughness of fracture were different. Fracture 3 is resin of integrate circuit, which forms roughness, disfigurement and hole. The surface topography of fracture 3 is the most complicated in 6 fractures of PCB, and the fractal dimension with 1.415 is the biggest. The more regular is surface topography of fracture 2, 5, 6, the smaller is fractal dimension. The fracture 1 and 4 with fluvial pattern come from the hard plastic, the fractal dimensions is between fracture 3 and 2, 5 and 6. The fractal dimensions of fracture morphology from the biggest down to the smallest are fracture 3, 1, 4, 5, 2 and 6, which accord with observing results by the human eyes. Those results show that the fracture morphology of PCB manifests fractal characteristics.