氮化硅纳米线制备过程中反应条件的影响

Effects of the Reaction Conditions in Preparation of Si_3N_4 Nanowires

采用X射线衍射和扫描电子显微镜技术,考察了溶胶-凝胶法制备氮化硅纳米线过程中反应条件(添加剂种类和含量、反应时间以及反应温度)对碳热还原产物组成和形貌的影响.结果表明,碳化后铁含量为5%(w)的凝胶,在1300℃下反应10h,Si3N4纳米线产率较高.添加剂的种类和含量不同,所得产物的组成和形貌也不相同.随着反应温度的升高或反应时间的延长,产物经历了一个从SiOx到Si2N2O再到Si3N4的转变过程.在有金属组分存在时,Si3N4纳米线由气-液-固过程形成.

X-ray diffraction （XRD） and scanning electron microscopy （SEM） were used to study the effects of reaction conditions （catalysts, reaction temperature and time） on the crystalline phases and morphologies of the carbothermal reaction products in the sol-gel synthesis of Si3N4 nanowires. The results showed that Si3N4 nanowires could be obtained with high yield by using xerogel, which produced a mixture with 5% （w） Fe after carbonization, with a controlling reaction temperature and time of 1300 ℃ and 10 h, respectively. The products obtained by using different additives had different crystalline phases. The content of additives also influenced the morphologies of the products. With increasing the reaction temperature or extending the reaction time, the products underwent a phase transformation of SiOx→Si2N2O→Si3N4. In the presence of metals, Si3N4 nanowires were produced with the help of the vapor-liquidsolid mechanism.