熔盐反应氧化Si_3N_4粉制备莫来石晶须的研究  

Preparation and Characterization of Mullite Whiskers from α-Si_3N_4 Powders by Molten Salt Synthesis

作　　者：杜炜 艾超前 杜毅帆 王伟 张荣兰[2] DU Wei;AI Chaoqian;DU Yifan;WANG Wei;ZHANG Ronglan(College of Environment Science and Engineering,Key Laboratory of Subsurface Hydrology and Ecology in Arid Areas,Ministry of Education,Chang'an University,Xi'an 710054,China;Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of Ministry of Education,Xi'an 710127,China)

机构地区：[1]长安大学环境科学与工程学院旱区地下水文与生态效应教育部重点实验室,西安710054 [2]西北大学合成与功能分子化学教育部重点实验室,西安710127

出　　处：《中国陶瓷》2019年第1期10-14,共5页China Ceramics

基　　金：国家自然科学基金(51678059);陕西省自然科学基金(2016JM5065);教育部留学回国人员启动基金;长安大学中央高校基本科研业务费(300102298202);陕西省土地整治重点实验室开放基金项目(2018-JC10)

摘　　要：通过熔盐(Al_2(SO_4)_3+Na_2SO_4)和Si_3N_4粉体之间的化学反应合成了莫来石晶须,采用扫描电子显微镜(SEM)、高分辨透射电子显微镜(HRTEM)、X射线粉末衍射(XRD)、傅里叶变换红外光谱(FT-IR)和热重分析(TG-DSC)对合成的莫来石晶须进行了研究。SEM的观测结果表明,莫来石晶须的直径100～300 nm,长度可到达几个微米。HRTEM的研究显示,晶须的晶面间距为0.27 nm,与莫来石相[220]晶面上的晶面间距正好符合。莫来石晶须的生长可用循环氧化-溶解机理进行解释,在此过程中SO_3对SiO_2表面层的刻蚀起着至关重要的作用。Mullite whiskers were prepared through chemical reactions between molten salts(Al2(SO4)3+Na2SO4) and Si3N4 powders. The resulting whiskers, as well as the conversion mechanism, have been investigated by Scanning electron microscopy(SEM), High resolution transmission electron microscopy(HRTEM), X-ray diffraction(XRD), Fourier transform infrared spectroscopy(FT-IR), and thermogravimetric analysis(TG-DSC) techniques. SEM studies show that diameter of the mullite whiskers was in the range of 100 ~ 300 nm and their length was several microns. HRTEM studies revealed these whiskers with lattice spacing about 0.27 nm corresponding to the growth direction of [220] crystal plane spacing of mullite. The whiskers growth can be explained by the oxidation-dissolution process, in which both the formation of SO3 and the etching of SiO2 play key roles.

关 键 词：晶须 熔盐合成 陶瓷 扫描电镜 

分 类 号：TQ174.758.1[化学工程—陶瓷工业]