B4C陶瓷在Na2SO4-Al2（SO4）3复合熔盐介质中的化学反应研究

The Chemical Reactions Investigation of B4C Ceramics in the Na2SO4-Al2（SO4）3 Molten Salts System

B4C陶瓷具有优异的热中子俘获能力而用于核能发电领域,这种核反应控制材料的热稳定性和化学稳定性引起了广泛关注。本文研究了B4C陶瓷在Na2SO4-Al2（SO4）3复合熔盐介质中的反应性能,采用热重分析（TG-DTA）、X射线粉末衍射（XRD）和傅里叶变换红外光谱（FT-IR）技术研究了熔盐反应产物的组成和结构。利用电子扫描显微镜（SEM）、高分辨透射电子显微镜（HRTEM）研究了产物的微观形貌与组成。结果表明,900℃的Na2SO4-Al2（SO4）3复合熔盐可与B4C反应合成Al18B4O33相晶须,晶须直径100300 nm,长度达到几个微米。提出氧化-溶解循环机理解释了熔盐反应及其硼酸铝晶须的生长过程。

B4C ceramics is excellent nuclear reaction control materials in nuclear power generation field due to its high thermal neutron capture capability, thermal stability and chemical stability. Chemical reactions of B4C with Na2SO4-Al2（SO4）3 molten salts system were studied in this paper, and Thermogravimetric analysis（TG-DTA）, X-ray diffraction（XRD）, Fourier transform-infrared spectroscopy（FT-IR） were employed to characterize the phase composition and identification of final product. Moreover, Scanning electron microscope（SEM） and High resolution transmission electron microscopy（HRTEM） were used to investigate the microstructure morphology and the interplanar spacing of Al18B4O33 whiskers. The results show that B4C ceramics can react with molten salts to form Al18B4O33 whiskers, and average diameter of whiskers is in range of 100 300 nm and length was several microns. An oxidation-dissolution cycle mechanism is proposed to explain the molten salts reactions and Al18B4O33 whiskers growth.