This work addresses a long standing question in the field of mechanochemistry, namely the role of mesostructure in the initiation of self-propagating high-temperature reactions in exothermic chemical systems, commonly referred to as ignition. In an attempt to find robust evidence in this regard, we compare the ignition behaviour of equimolar Al–Ni powder mixtures and equimolar Al–Ni multilayers. To achieve the best possible control of experimental conditions and allowing high reproducibility, we used elemental powders sieved in the range between 20 μm and 44 μm, and multilayers with bi-layer thickness between 10 nm and 800 nm. We carried out systematic ball milling experiments involving pristine powder mixtures and multilayers as well as a mix of pristine material and material prone to ignition suitably prepared. Experimental findings suggest that pristine powder mixtures and multilayers with bi-layer thickness of 240 nm have analogous ignition behaviour. Along the same lines, data suggest that pristine powder mixtures undergo ignition when they attain a mesostructure similar to that of multilayers with bi-layer thickness of 10 nm.

中文翻译：

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等摩尔 Al-Ni 粉末混合物和多层中自蔓延反应的机械化学点火

这项工作解决了机械化学领域一个长期存在的问题，即介观结构在放热化学系统中引发自蔓延高温反应（通常称为点火）中的作用。为了找到这方面强有力的证据，我们比较了等摩尔 Al-Ni 粉末混合物和等摩尔 Al-Ni 多层的点火行为。为了实现对实验条件的最佳控制并实现高再现性，我们使用了筛分范围在 20 μm 至 44 μm 之间的元素粉末，以及双层厚度在 10 nm 至 800 nm 之间的多层材料。我们进行了系统的球磨实验，涉及原始粉末混合物和多层粉末以及原始材料和经过适当制备的易燃材料的混合物。实验结果表明，原始粉末混合物和双层厚度为 240 nm 的多层粉末具有类似的点燃行为。同样，数据表明，原始粉末混合物在获得类似于双层厚度为 10 nm 的多层结构的介观结构时会发生点燃。