(武汉理工大学 材料复合新技术国家重点实验室，武汉 430070)
摘 要: 利用透射电子显微镜(TEM)在纳米尺度上直接观察由氮化硅分解出的硅蒸气在蒸发-凝聚过程中产生的分形生长这一实验现象，结合相对应的有限扩散凝聚(DLA)模型以及核晶凝聚(NA)模型，对所获得的分形结构进行了描述和讨论，并探讨了分形生长的发生机理。同时，由实验中所拍摄的一组照片计算其分形维数，分别为Dm1 ≈1.09，Dm2 ≈1.52，Dm3 ≈1.78，其中Dm3 ≈1.78与DLA模型的理论预测值以及数值模拟结果较一致。
关键字: 分形生长； 氮化硅陶瓷； 维数
（State Key Laboratory of Advanced Technology for Materials Synthesis and Process,
Wuhan University of Technology, Wuhan 430070, P.R.China）
Abstract:The fractal structure was described and the growth mechanism was studied according to an experimental study of fractal growth. The fractal growth process generated by evaporation-condensation of Si(g) decomposed from Si3N4 in sintered silicon nitride, can be observed with TEM in nanometer scale. Also, the fractal dimension was calculated as Dm1≈1.09, Dm2 ≈1.52, Dm3 ≈1.78, respectively. The result Dm3 ≈1.78 was in agreement with those reported.
Key words: fractal growth; Si3N4 ceramics; fractal dimension
