纳米四氧化三铁的制备修饰及磁场的影响物理化学专业论文.docxVIP

优秀毕业论文 精品参考文献资料 Fe304与十二烷基硫酸钠的物质的量的比约为 Fe304与十二烷基硫酸钠的物质的量的比约为8：l时，表面分散效果最好；比较两 种加热方式发现，水浴法加热得到的Fe304较大，形貌也有所变化，而用沸腾回流 法加热，更有利于生成小颗粒且分散性好的纳米Fe304。另外，改变表面活性剂的 加入时间，比较一次法和二次法，一次法更容易生成粒径较小且分散效果较好的 纳米四氧化三铁；二次法也可得到分散性较好的纳米Fe304，但产物粒径较大。 (3)磁场对纳米四氧化三铁液相转化的影响 讨论在磁场作用下，纳米四氧化三铁的形貌、粒径的变化情况。同时，改变 磁场强度、反应时间、反应温度及氧气用量等条件探讨各种参数对纳米四氧化三 铁液相相转化的影响。结果表明，磁场对纳米Fe304粒子的排布、分散性及粒径大 小都具有影响，弱磁场的作用可使Fe304粒子沿一定方向排列，使其呈现链状排布， 随着磁场强度的增加，微粒的粒径有所减小，但均匀性、分散性变差。磁场对纳 米Fe304液相转化具有影响，磁场强度的增加、通02量及反应温度的升高均有利 于Fe304的液相转化；在强磁场(E=250mT)作用下，通入空气，控制反应温度为 100。C，沸腾回流36小时后纳米Fe304可以基本上转化为cc—Fe203。 关键词：四氧化三铁纳米粒子液相合成表面修饰液相转化 Ⅱ AbstractDue Abstract Due to their special physical and chemical properties，narlo-sized magnetic particles put up different physical and chemical characteristics compared with general materials． The studies on nano—sized magnetic particles have become one of the most interesting fields in this world．Recently,although there are many preparing methods reported，the excellent technology which call satisfy the industrial producing is seldom heard． Compared with many chemical methods，and according to the valuable experience accumulated in the laboratory for many years，the author continues to prepare the nano·sized magnetic particles by the method of oxidation—coprecipitation phase transformation．The conditions of preparing well proportioned，size．controlled nano。sized magnetic powder material are discussed．The uniformity and dispersion of the Fe304 nano·particles is developed by surfactant．Meanwhile，the effect and the transformation law of the Fe304 nano—particles in magnetic field are also studied for its application in practice． The main research aspects are as follows： (1)The preparation ofnano—sized magnetite particles． Use two heating styles·-·-·---dynamic boiling reflux method and static water bath method，change the pH value，temperature，time and the dosage of H202 of the system， study the effect of the generation and the particle size of Fe304 nano-particles in all conditions，and discuss t