Highly monodisperse core-shell particles created by solid-state reactions
Highly monodisperse core-shell particles created by solid-state reactions
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DOI：
10.1038/nmat3077
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发表时间：
2011-09-01
期刊：
影响因子：
41.2
通讯作者：
Dahmen, U.
中科院分区：
文献类型：
--
作者：
Radmilovic, V.;Ophus, C.;Dahmen, U.
颗粒的尺寸分布对纳米材料的许多性质至关重要，对于其强度来自纳米级沉淀物分散的合金类的机械行为同样重要。然而，通过固态沉淀形成的粒度分布通常不能很好地控制。在这里，我们证明，通过在铝钪锂合金的核-壳沉淀的例子，一种方法来形成高度单分散的颗粒尺寸分布，通过简单的固态反应。该方法涉及使用两步热处理，由此在高温下形成的核提供用于在较低温度下生长壳的模板。如果允许核心生长到足够的尺寸，外壳就会在“尺寸聚焦”状态下发展，其中较小的颗粒比较大的颗粒生长得更快。这些结果表明，在类似的系统中，通过简单的变化，在热处理中操纵沉淀物的尺寸分布的策略。
The size distribution of particles, which is essential for many properties of nanomaterials, is equally important for the mechanical behaviour of the class of alloys whose strength derives from a dispersion of nanoscale precipitates. However, particle size distributions formed by solid-state precipitation are generally not well controlled. Here we demonstrate, through the example of core-shell precipitates in Al-Sc-Li alloys, an approach to forming highly monodisperse particle size distributions by simple solid-state reactions. The approach involves the use of a two-step heat treatment, whereby the core formed at high temperature provides a template for growth of the shell at lower temperature. If the core is allowed to grow to a sufficient size, the shell develops in a 'size focusing' regime, where smaller particles grow faster than larger ones. These results suggest strategies for manipulating precipitate size distributions in similar systems through simple variations in thermal treatments.