【摘要】 研究了使用SiO₂为氧源合成氮氧化硅时,SiO₂的结晶状态对氮氧化硅形貌的影响。实验使用的SiO₂分别为气相白炭黑和晶体石英粉末,硅固体为平均粒径1.15μm左右的粉末。使用X射线衍射仪对合成物进行物相分析,并用扫描电子显微镜观察其形貌。结果表明:使用气相白炭黑为氧源时,在1 380℃保温4h的条件下,硅粉与气相白炭黑的物质的量比为2.0∶1².6∶1可得到纤维状氮氧化硅;以晶态石英为氧源时,在1 450℃保温4h的条件下,固定硅粉与晶态石英的物质的量比为1.5∶1可得到颗粒状氮氧化硅。本工作通过对Si-N-O体系的热力学分析,讨论了不同形貌的氮氧化硅粉体的形成机制。更多还原

【Abstract】 The effect of the form of SiO₂ on the morphology of synthesized silicon oxynitride was investigated when it was used as the oxidant.The fumed silica and crystalline quartz powders were used respectively,and the average particle size of silicon powders was 1.15μm.Phase analysis was carried out with an X-ray diffractometer,and morphology observation was performed with a scanning electron microscope.The results show that when fumed silica was used as the oxidant,silicon oxynitride fibers were obtained when mixtures of oxidant and silicon powders were held at 1 380℃ for 4 h,and the molar ratio of oxidant to silicon was in the range of 2.0∶1—2.6∶1.When crystalline quartz was used as the oxidant,granular silicon oxynitride particles were obtained by holding the mixture at 1 450 ℃ for 4 h,with the molar ratio of silicon to quartz fixed at 1.5∶1.The mechanisms for the formation of silicon oxynitride of different morphology were discussed,with the aid of thermodynamics analysis of the Si-N-O system.更多还原