(武漢理工大學(xué) 材料復(fù)合新技術(shù)國家重點實驗室，武漢 430070)
摘 要: 利用透射電子顯微鏡(TEM)在納米尺度上直接觀察由氮化硅分解出的硅蒸氣在蒸發(fā)-凝聚過程中產(chǎn)生的分形生長這一實驗現(xiàn)象，結(jié)合相對應(yīng)的有限擴(kuò)散凝聚(DLA)模型以及核晶凝聚(NA)模型，對所獲得的分形結(jié)構(gòu)進(jìn)行了描述和討論，并探討了分形生長的發(fā)生機(jī)理。同時，由實驗中所拍攝的一組照片計算其分形維數(shù)，分別為Dm1 ≈1.09，Dm2 ≈1.52，Dm3 ≈1.78，其中Dm3 ≈1.78與DLA模型的理論預(yù)測值以及數(shù)值模擬結(jié)果較一致。
關(guān)鍵字: 分形生長； 氮化硅陶瓷； 維數(shù)
（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
