Combustion phenomena induced by ball milling

Ball milling induces self-sustaining reactions in sufficiently exothermic powder mixtures. Combustion occurs after some activation time, when the powder reaches a well defined critical state. Investigating the nature of this state and the processes leading to ignition are used as a vehicle to learn about the mechanism of mechanochemical reactions in general. A possible framework is proposed to describe the processes. The effects of a single collisions play the central role. The more fundamental atomic scale events and the global kinetics of the milling processes are also considered. Experimental investigations of the ignition of combustion are reviewed with emphasis on systematic studies relating the reaction parameters and the ignition time. Unusual combustion phenomena such as the interrupted combustion effect anf the mutual suppression of combustion are discussed.