液相先驱体转化结合溶胶凝胶法合成ZrC-SiC纳米复合粉体

Syntheses of ZrC-SiC Nano-composite Powders via Liquid Precursor Conversion and Sol-Gel Method

以八水合氧氯化锆为锆源、正硅酸乙酯为硅源、蔗糖为碳源,采用液相先驱体转化结合溶胶凝胶法合成ZrCSiC纳米复合粉体。借助傅立叶红外光谱仪分析了有机锆先驱体的官能团,借助X射线衍射仪和扫描电子显微镜研究了Si/Zr摩尔比对复合粉体物相组成与显微形貌的影响。研究表明:有机锆先驱体具有链状或网状结构;1450℃烧成并保温2h,Si/Zr摩尔比0.28时复合粉体中仍存在未反应的m-ZrO_2相,Si/Zr摩尔比增加至1.11、2.56、5.88、23.17时均合成了纯相ZrC-SiC纳米复合粉体;随着Si/Zr摩尔比的增加,复合粉体粒径变化不大;Si/Zr摩尔比为2.56时平均粒径仅90nm,且元素分布均匀。

ZrC-SiC nano-composite powders were synthesized via liquid precursor conversion and sol-gel method,using zirconium oxychloride octahydrate as zirconium source,tetraethoxysilance as silica source and sucrose as carbon source.Functional groups of zirconium-containing polymer precursor were analyzed by fourier transform infrared spectrometer.Effects of Si/Zr molar radio on phase composition and microstructure of samples were investigated by X-ray diffractometer and scanning electronic microscopy,respectively.It is shown that the zirconium-containing polymer precursor has a chain-like or network-like structure.After sinterd at 1450 ℃ for 2 h,there is still unreactive m-ZrO_2 phase in the sample whose Si/Zr molar radio is 0.28.When Si/Zr molar radio increases to 1.11,2.56,5.88 and 23.17,nearly pure ZrC-SiC nano-composite powders can be synthesized.The powder size changes little with the increasing of Si/Zr molar ratio.Composite powders with an average particle size of 90 nm and evenly elements distribution are obtained when Si/Zr molar ratio is 2.56.