Mechanochemical transformations: Bridging the gap between global and local kinetics ​

Deeply rooted in metallurgy and materials science, mechanochemistry is presently one of the most rapidly growing research subjects in chemistry. Mechanochemical reactions are generally performed in ball mills, where the powders are subjected to forging events during individual collisions. Precisely the complex milling dynamics make the investigation of the reaction kinetics on a local scale extremely challenging. The thesis endeavours to gain insight into the local kinetics from macroscopic experimental evidence. To this aim, we developed a kinetic model that rationalizes the kinetics of mechanochemical transformations based on a few assumptions that allow capturing the essential features of mechanical processing. Combining the model with the quantitative description of the experimental and processing conditions enabled us to best fit the experimental kinetic curves and establish correlations between transformation rates and processing variables and parameters, giving us a rule of thumb to progress in the understanding of mechanochemical kinetics. Furthermore, the accuracy of our experiments revealed the link between global and local kinetics, demonstrating that local deformation processes have the potential to drive physical and chemical systems far from thermodynamic equilibrium, which can eventually result in a broad range of unexpected outcomes.