气相反应法合成超细粉末过程中的r~＊叶和晶型的研究

The Study of Critical Nucleus Radius r￣* and Crystallinity of Ultrafine Powders Synthesized by CVD

本文以ＳｉＣｌ４－ＮＨ３、ＳｉＣｌ４－Ｏ２、ＳｉＣｌ４－Ｎ２－Ｈ２、ＴｉＣｌ４－ＮＨ３－Ｈ２、ＴｉＣｌ４－Ｎ２－Ｈ２、ＴｉＣｌ４－Ｏ２、ＡｌＣｌ３－Ｏ２等为体系，运用均匀成核理论，研究了平衡常数Ｋｐ、过饱和比Ｓ及临界核半径，ｒ＊等因素对气相反应法中超细粉末的形成及粉末结构状态的影响．结果表明，当２ｒ＊大于某物质的晶格常数时，用气相反应法得到的该物质的超细粉末一般为晶体粉末，反之则得到无定形粉末．

Homogeneous nucleation and particle growth of the SiCl4-O2, TiCl4-NH3-H2, TiCl4-N2-H2, TiCl4O2, AlCl3-O2 system have been studied in this paper. The effect of Kp, S, r* on the formation and the crystallinity of ultrafine powders have been discussed. It was indicated that while the 2r* was larger than the amounts of the lattice parameter of individual material the powders were preferred to form crystalline state and vice versa.