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首页> 外文期刊>Journal of Non-Crystalline Solids: A Journal Devoted to Oxide, Halide, Chalcogenide and Metallic Glasses, Amorphous Semiconductors, Non-Crystalline Films, Glass-Ceramics and Glassy Composites >The evolution of structure induced by intensive milling in the system 2Bi(2)O(3) center dot 3TiO(2)
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The evolution of structure induced by intensive milling in the system 2Bi(2)O(3) center dot 3TiO(2)

机译：密集铣削在系统2Bi（2）O（3）中心点3TiO（2）中引起的结构演变

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Concurrent mechanochemical treatment of either a stoichiometric 2Bi(2)O(3)(.)3TiO(2) powder mixture or (pulverized) Bi4Ti3O12 compound was performed in a planetary ball mill. Relevant structural parameters: crystallite size, amount of amorphous phase and the transformed fraction (as a result of chemical reaction between Bi2O3 and TiO2) of the powders milled for various milling times and intensities were derived from X-ray powder diffraction data. The obtained structural parameters were used to follow the kinetics of the reduction of crystallite size, amorphous phase formation and chemical reaction. In the powder mixture, during the early stage of mechanochemical treatment the Bi-2(CO3)O-2 phase was found as an intermediate product which transformed into the highly amorphized Bi4Ti3O12 phase as the milling progressed. On the other hand, mechanochemical treatment of Bi4Ti3O12 powder induced a gradual deformation of the crystal lattice and destruction of the perovskite-type structure. However, in both cases, after a certain milling time, a very disordered, amorphousanocrystalline structure was obtained. It was demonstrated that in the steady state, the amorphousanocrystalline phase ratio depends on the milling conditions. Higher milling intensities induce 'nanocrystallization' of the amorphous phase, i.e., precipitation of crystallites with an average size below 20 nm. A kinetic model involving a nanocrystalline -> amorphous reaction, in which the forward and reverse reaction were first-order was postulated and used to analyze the formation of an amorphous phase. (c) 2006 Elsevier B.V. All rights reserved.
机译：在行星式球磨机中进行化学计量的2Bi（2）O（3）（。）3TiO（2）粉末混合物或（粉碎的）Bi4Ti3O12化合物的同时机械化学处理。相关的结构参数：从X射线粉末衍射数据中得出了在各种研磨时间和强度下研磨的粉末的微晶尺寸，无定形相的量和转化分数（由于Bi2O3和TiO2之间的化学反应的结果）。所获得的结构参数用于追踪微晶尺寸减小，非晶相形成和化学反应的动力学。在粉末混合物中，在机械化学处理的早期阶段，发现Bi-2（CO3）O-2相是一种中间产物，随着研磨的进行，其转变为高度非晶化的Bi4Ti3O12相。另一方面，Bi 4 Ti 3 O 12粉末的机械化学处理引起了晶格的逐渐变形和钙钛矿型结构的破坏。但是，在两种情况下，经过一定的研磨时间后，都获得了非常无序的非晶/纳米晶体结构。已经证明，在稳态下，非晶/纳米晶相比取决于研磨条件。较高的研磨强度引起非​​晶相的“纳米晶化”，即平均尺寸低于20nm的微晶沉淀。提出了一个涉及纳米晶体→非晶态反应的动力学模型，其中正反反应是一阶反应，并用于分析非晶态相的形成。 （c）2006 Elsevier B.V.保留所有权利。

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