Study On Nanometer Rare Earth Oxide Synthesized By Mechanical Solid-State-Chemistry-Reaction

In this thesis, mechanically alloying, solid state reaction, nanometer materials and technology, preparation and properties of rare earth oxides, especially ceria(CeO2) are reviewed in details. To counter troubles and limits of preparing method of rare earth oxides, mechanically alloying is first united with solid state reaction and mechanical solid-state-chemistry-reaction is used to prepare nanometer rare earth oxides. The thermal change, phase, appearance, size were studied by TG-DTA, XRD, SEM, TEM. We have obtained a lot of high quality nanometer rare earth oxides. As a studying result of two systems reaction mechanism, some important theoretical basis are obtained for "mechanical solid-state-chemistry-reaction". The main creative results and new progress in this thesis are presented as follows: 1. Getting a simple and direct, easy operation , good effect method by united mechanically alloying with solid state chemical reaction ,and put to use it in salt-salt system , preparing nanometer rare earth oxides .A lot of precursors of Ce, La, Pr and Nd elements are prepared by with H2C2O4 and NH4HCO3. 2. According to mechanism of thermal decomposition , using data of thermal analysis (TG-DTA) and controlling appropriate temperature parameter. CeO2, La2O3, Pr6O11 and Nd2O3 are obtained one after another .The size of these products is under 100nm. Their appearances are different: spherical, reticulation and plate-like. 3. In the process of mechanical solid-state-chemistry-reaction, the function of cutting power is enlarged, and so, spreading speed is increased. This will make reactors and products thinner, increase reaction speed and shorten reaction speed. 4. Precursor has low decomposition temperature. They can decompose at medium or low temperature, and product rare earth oxides. It will reduce producing cost of industry. 5. Mechanical solid-state-chemistry-reaction can realize reactor's quantitation, avoid using solvent, and then can reduce subsidiary products'discharging at a largest degree. So industrial raw material can be saved, and environment pollution can be decreased or avoided. 6. Polishing characteristics of nanometer CeO2 is studied: The temperature may effect polishing property at thermal decomposition , CeO2 active will reduce bring about impair polishing results when excessive; while lack of temperature will make CeO2 hardness reduce and bring about impair polishing results, too. 7. Effect of polishing time on polishing quality is studied. The relation between polishing quality and polishing time is straight line. With the increasing of polishing time, polishing quality increases, too, but increasing range becomes smaller and smaller. The results indicate that, mechanical solid-state-chemistry-reaction is a simple, easy operation, economic, environmental protection method with which nanometer rare earth oxides can be prepared.