晶态稀土氧化物发光陶瓷材料的超高压高温合成及其性能研究

Owing to their novel properties, rare earth ceramics are intensively studied. Under high pressure, the distance and allign mode of atom and molecule can be effectively changed. Many new phenomena, new laws, new substances, new properties and new materials have been acheived under high pressure. The properties of ceramics are closely related to the precursors employed and preparation conditions. Materials derived from coordination polymers always demonstrate excellent properties such as high reactivity and catalytic ability. No reports have appeared on the preparation of ceramics with coordination polymers or derived oxides obtained after calcinations as the precursors. Based on the successful preparation of a series of rare earth coordination polymers, in this study, rare earth coordination polymers built from different units were designed selected as the precursor and their corresponding luminescent ceramics such as crystalline Y2O3:Eu3+ and (Y1-xGdx)2O3:Eu3+ were prepared by different way under ultrahigh pressure and temperature. The effect of the unit of coordination polymers, pressure and temperature, also the increase and decrease mode on their assembly, crystal structure and luminescent properties will be investigated. The luminescent properties will be measured and calculated by the dielectric theory of complex crystals. The property-controllable law wil be obtained. It may provide therorctical principle and prepartion method for the preparation of function-directed ceramics and also give guideline for the design and preparation of other materials.

稀土陶瓷由于其独特的性能备受关注。高压能够有效地改变物质的原子、分子间距及其集成方式，从而获得许多新现象、新规律、新物质、新性能和新材料。陶瓷的性能与制备所用的前驱体以及制备条件密切相关。以配位聚合物为前驱体制备的材料住往表现出许多优异的特性，未见以配位聚合物或以经煅烧配位聚合物所得氧化物为前驱体制备陶瓷材料的研究。在成功制备系列稀土配位聚合物材料的基础上，本研究拟设计具有不同结构基元组成的稀土配位聚合物为前驱体，采用不同路线在超高压高温条件下制备晶态Y2O3:Eu3+、(Y1-xGdx)2O3:Eu3+等发光陶瓷材料。详细考察配位聚合物前驱体的基元结构、压力、温度及压力和温度的升降模式等对其聚集方式、晶体结构及其光学性能的影响。测试材料的发光性能，运用复杂晶体介电理论进行计算，获得材料性能可控的规律。为功能导向陶瓷的制备提供理论依据和方法路线，同时也为其它材料的设计与制备提供指导。

稀土陶瓷由于其独特的性能备受关注，其性能与制备所用的前驱体以及制备条件密切相关。以配位聚合物为前驱体制备的材料住往表现出许多优异的特性。研究选取系列有机羧酸配体(考察碳链的长度、环的种类等）如草酸，丁二酸，戊二酸，己二酸，对苯二甲酸等二元羧酸为有机连接配体，钇为中心离子，采用微波快速合成法、水热法等制备了系列钇基配位聚合物并进行铕离子掺杂。然后采用相同的办法制备了其它稀土配位聚合物微/纳米材料。进而以其为前驱体，详细考察配位聚合物前驱体的基元结构、压力、温度及压力和温度的升降模式等对其聚集方式、晶体结构及其光学性能的影响。研究结果表明，直接高压处理前驱体时往往存在析碳现象，控制制备条件可得到稀土氧化物/碳复合材料、碱式碳酸盐/碳复合材料、稀土碳化物等。此外，所得碳可以是无定型碳或石墨等。进而将所得的稀土配位聚合物先在空气煅烧得到其相应的氧化物，然后在超高压条件下进行处理，得到了相应的氧化物陶瓷。结果表明，材料的硬度随着所用前驱体按一定规律变化。此外，材料的物相和发光性能等也受压力的影响。项目为其它配位聚合物材料在超高压条件下的制备提供了理论基础和指导。