摘要
用硝酸盐-柠檬酸溶胶凝胶自燃法获得锰锌铁氧体（MZF）纳米晶。采用TG-DTA，XRD、VSM等方法对不同种类pH调节剂和不同pH值处理的凝胶热分解过程及产物的性能进行了表征结果表明：溶胶pH值和溶胶pH值调节剂对锰锌铁氧体纳米晶的形成有很大的关系。氨水调节凝胶的自燃点温度会随着溶胶的pH值从3．4增加到10而从196℃变到207℃。用乙二胺调节pH值，可以控制锰锌铁氧体纳米晶颗粒在19nm和57nm间变化。乙二胺调节pH值的系统热分解反应速度比氨水调节的系统反应速度慢，其反应生成粉体的饱和磁化强度为60emu／g，而氨水调节的系统生成粉体的饱和磁化强度为70emu／g。乙二胺调节系统生成粉体的矫顽力在pH值大于7后会有所增大。
MnZn ferrite （MZF） nano-erystallites were synthesized by sol-gel and auto-combustion method. The thermal decomposition process and the properties of the precursors are investigated by different pH regulators via TG-DTA, XRD, and VSM techniques. The results show that the pH value in sol and the pH value regulators have much relation with the formation of the MZF nanocrystallites. The ignition point of the gel increased from 196℃ to 207℃ with the pH value increasing from 3.4 to 10 in ammonia adjusted system. By adjusting pH value with ethylenediamine, the particle size can be controlled from 19nm to 57nm. The thermal decomposition reaction speed it, ethylenediamine adjusted system is slower than in the ammonia adjusted system does. The saturation magnetization of the powder made in ethylenediamine adjusted system is 60 emu/g, and is about 70 emu/g in ammonia adjusted system. The coercive force of the powder in ethylenediamine adjusted system is increased when the pH value above 7.
基金
上海市科学技术委员会纳米科技计划资助项目（0652nm046）
国家自然科学基金资助项目（10504019）ACKNOWLEDGEMENTS This work was supported by Shanghai Nanotechnology Promotion Center and the Science ＆ Technology Committee of Shanghai Municipality （No. 0652nm046）, the National Natural Science Foundation of China （Nos.10504019, 10674092）, and the Foundation of Shanghai Education Committee, Shanghai Leading Academic Discipline Project（No. T0104）.
关键词
锰锌铁氧体纳米晶
热分析
PH值
pH值调节剂
MnZn ferrite nanocrystallite
thermal analysis
pH value
pH value regulators
