α-Al_2O_3晶须形貌及其生长过程研究

A STUDY ON MORPHOLOGY AND GROWTH PROCESS OF α-Al_2O_3 WHISKERS

对所制备的α-Al_2O_3晶须的特殊形貌及其生长过程进行了研究。实验结果表明,该晶须的生长首先经过气态成核粒子在铝粉颗粒表面氧化层上或氧化铝基质表面成核,晶核可能以无定形、多晶或单晶的形式存在。认为晶须的生长是由于气相成核粒子在具有较高表面能的单晶态晶核表面上发生定向吸附的结果;由于温度或气相过饱和度的波动所引起的气相成核粒子的不同聚集状态可能是影响晶须径向生长稳定性和晶须内部结晶完整性的。主要因素。

In this paper,the specific morphology and growth process of α-Al_2O_3 whiskers are studied.Experimental results indicate that the first step in the whisker growth is the nucleation of the vaporized nuclei on the oxidized surface layer of aluminum powder particles or the surface of aluminum oxide substrates. Crystal nuclei may exist in the amorphous, polycrystalline and single crystal forms. It is suggested that the whisker growth results from the oriented adsorption of vapor-nuc-leating species on certain single-crystalline nucleus surface with relatively high surface energy, and the aggregate states of the species due to the fluctuation of temperature and supersaturation are probably the main factors affecting the growth stability and crystalline perfectness of the whiskers.