Ignition and Combustion of Mechanically Activated Powder Mixtures (Review). I. Ignition

This paper presents a critical review of experimental results and theoretical models for the effect of mechanical activation on the ignition of powder mixtures in gasless and filtration combustion and on the ignition of thermite compositions. It is shown that all available data unambiguously indicate an increase in the sensitivity of powder compositions to thermal initiation, but in the case of impact initiation, the sensitivity does not always increase. The change in the sensitivity is due to the combined effect of two factors: an improvement in the contact between reactants and a decrease in the activation energy of the chemical reaction. It is proposed to use the mechanical activation factor taking into account the change in contact area and activation energy to describe the sensitivity of activated compositions.