Microstructural evolution during deformation of tin dioxide nanoparticles in a comminution process
Microstructural evolution during deformation of tin dioxide nanoparticles in a comminution process
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DOI：
10.1016/j.actamat.2009.02.049
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发表时间：
2009-06-01
期刊：
影响因子：
9.4
通讯作者：
Peukert, W.
中科院分区：
文献类型：
--
作者：
Armstrong, P.;Knieke, C.;Peukert, W.
如果通过颗粒的稳定化防止团聚，则可以通过在搅拌介质米尔斯中的湿研磨来生产纳米颗粒。由于在较低的纳米尺度的断裂机制尚未了解，我们研究了二氧化锡颗粒内的微观结构的演变。静电稳定化允许形成平均粒径为25 nm的二氧化锡，通过动态光散射测量。高分辨率透射电子显微镜（HRTEM）图像显示颗粒远低于10 nm，平均微晶尺寸为9 nm，从X射线衍射通过应用Rietveld细化方法。此外，TEM和HRTEM分析进行了详细的洞察微观结构的影响，控制研磨过程。显微镜显示了令人惊讶的丰富的现象，包括剪切带的形成，孪生和堆垛层错，直接影响磨削行为。有趣的是，陶瓷纳米颗粒不仅表现出预期的脆性断裂的断裂模式，而且还表现出许多塑性变形的痕迹。为了比较，使用分子动力学模拟了直径达30 nm的颗粒的单轴压缩。模拟颗粒与真实的样品共享微观结构细节，最重要的是导致显著塑性变形的剪切带。在磨机中的多个颗粒应力事件期间产生的内部微观结构以及在模拟中观察到的内部微观结构与断裂机制和实验观察到的研磨极限直接相关。(C)2009 Acta Materialia Inc.由爱思唯尔有限公司出版。保留所有权利。
Nanoparticles can be produced by wet grinding in stirred media mills if agglomeration is prevented by stabilization of the particles. Since the fracture mechanisms at the lower nanoscale are not yet understood, we studied the evolution of the microstructure within tin dioxide particles. Electrostatic stabilization allows the formation of tin dioxide with a mean particle size of 25 nm as measured by dynamic light scattering. High-resolution transmission electron microscopy (HRTEM) images show particles well below 10 run and mean crystallite sizes of 9 nm were obtained from X-ray diffraction by applying the Rietveld refinement method. Additionally, TEM and HRTEM analyses were conducted to gain detailed insight into the microstructural effects governing the grinding process. Microscopy revealed surprisingly rich phenomena including the formation of shear bands, twinning and stacking faults that directly affect the grinding behavior. Interestingly the ceramic nanoparticles showed not only fracture patterns expected from brittle fracture but also many traces of plastic deformation. For comparison the uniaxial compression of particles up to 30 nm in diameter was simulated using molecular dynamics. The simulated particles shared microstructural details with the real samples, most importantly the shear bands which lead to significant plastic deformation. The internal microstructure produced during multiple particle stressing events in the mill and also observed in the simulations is directly linked to the fracture mechanism and the experimentally observed grinding limit. (C) 2009 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.