Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parco Area Delle Scienze 17/A, Parma 43124, Italy.
Biopharmanet-TEC, University of Parma, Parco Area Delle Scienze 27/A, Parma 43124, Italy.
Faraday Discuss. 2023 Jan 5;241(0):289-305. doi: 10.1039/d2fd00104g.
The debate on the mechanisms which underpin mechanochemical reactions ball mill grinding is still open. Our ability to accurately measure the microstructural (crystal size and microstrain) evolution of materials under milling conditions as well as their phase composition as a function of time is key to the in-depth understanding of the kinetics and driving forces of mechanochemical transformations. Furthermore, all ball milling reactions end with a steady state or milling equilibrium - represented by a specific phase composition and relative microstructure - that does not change as long as the milling conditions are maintained. The use of a standard sample is essential to determine the instrumental contribution to the X-ray powder diffraction (XRPD) peak broadening for time-resolved (TRIS) monitoring of mechanochemical reactions under conditions. Using TRIS-XRPD on a ball milling setup, coupled with low-energy synchrotron radiation, we investigated different data acquisition and analysis strategies on a silicon standard powder. The diffraction geometry and the microstructural evolution of the standard itself have been studied to model the instrumental contribution to XRPD peak broadening throughout the grinding activity. Previously proposed functions are here challenged and further developed. Importantly, we show that minor drifts of the jar position do not affect the instrumental resolution function significantly. We here report and discuss the results of such investigations and their application to TRIS-XRPD datasets of inorganic and organic ball mill grinding reactions.
关于机械化学反应（球磨粉碎）所依赖的机制的争论仍未解决。我们能够准确测量在研磨条件下材料的微观结构（晶体尺寸和微应变）演变以及其随时间的相组成，这是深入了解机械化学转化动力学和驱动力的关键。此外，所有球磨反应最终都会达到稳态或研磨平衡——由特定的相组成和相对微观结构表示——只要研磨条件保持不变，就不会改变。使用标准样品对于确定在研磨条件下进行的机械化学反应的时间分辨（TRIS）监测中 X 射线粉末衍射（XRPD）峰展宽的仪器贡献至关重要。使用球磨装置上的 TRIS-XRPD 以及低能同步辐射，我们研究了硅标准粉末的不同数据采集和分析策略。研究了衍射几何形状和标准本身的微观结构演变，以在整个研磨过程中模拟仪器对 XRPD 峰展宽的贡献。本文还挑战了之前提出的函数，并对其进行了进一步的开发。重要的是，我们表明，罐位置的微小漂移不会对仪器分辨率函数产生显著影响。本文报告并讨论了这些研究的结果，并将其应用于无机和有机球磨研磨反应的 TRIS-XRPD 数据集。
