Self-sustaining reactions induced by ball milling: An overview

When a highly exothermic powder mixture is activated in a ball mill, a self-propagating process can be ignited after a certain activation time. Exploring the effects of material properties and milling conditions on the ignition time, combined with characterization of reactant mixtures approaching the critical state at ignition, provides useful information on the mechanical activation process. After ignition, the reaction propagates thermally, similar to an SHS process. In this paper, the principles of mechanically induced self-sustaining reactions (MSR) are summarized and their relationships with mechanochemistry and SHS are discussed. Numerous examples are given, some interesting from the point of view of fundamental understanding of the process, others are promising as the bases of practical applications.