低温微波水热法制备氧化钇稳定氧化锆

微波水热合成法是新型的纳米粉体材料制备方法,它与常规水热法相比,反应时间更短、反应温度更低,并且微波的非热效应影响产物晶型的形成。立方相氧化钇稳定氧化锆(YSZ)陶瓷材料是制作氧传感器、固体氧化物燃料电池及高温湿度传感器等多种功能元器件的核心原材料。采用可程序化控制的MARS-5微波消解仪实现了微波水热合成,反应温度100~120℃,反应时间1~5h,在强碱环境下制备氧化钇稳定氧化锆纳米粉体,而常规水热法制备氧化锆的温度一般为190~250℃。采用X射线衍射、热分析等方法,研究了温度、时间、pH和Y2O3含量对产物粒度和晶型的影响,使用了Rietveld方法进行定量分析、粒度计算。结果显示,与常规水热法相比,微波水热法不仅缩短了反应时间,并且影响产物的结构组成。分析表明,微波加速反应的机理可以用晶粒旋转驱动的晶粒聚合解释,而微波的介电加热效应,微波离子传导损耗等是加速化学反应的主要原因。

Microwave Hydrothermal Synthesis of Yttria Stabilized Zirconia at Low Temperature

Microwave hydrothermal(MH) is a new method of material synthesis.Many advantages of the MH synthesis are over the convention hydrothermal(CH),even shorter reacting time and lower temperature,the non-thermal effects of microwave will influence the formation of the crystal form.Yttria stabilized zirconia(YSZ)is the main material for preparing functional device such as oxygen sensor,solid state oxide fuel cell and high temperature humidity transducer.YSZ nano powder were prepared by MH with programmable MARS-5 microwave digester in strong basic media at temperature from 100～120℃ and time from 1 h to 5 h,whlie the temperature is 190～250 ℃ by CH.The influence of temperature,time,pH and Y2O3 content on the crystalline type and crystal size of YSZ were studied by XRD,thermal analysis and Rietveld method.The result shows that compared with CH,MH can reduce the reaction time,and influence the content of product.The advantages show that the grain aggregation of grain circumgyrate drive can be the mechanism of microwave accelerate,and the microwave dielectric heating effect and microwave ionic transmiting spoilage are the main courses for accelerating the chemical reactions.