Kinetics of mechanically activated high temperature synthesis of Ni3Al in the thermal explosion mode

We present the features of macrokinetics of phase formation during the solid-state synthesis in the mechanically milled 3Ni + Al mixtures. It was found that with milling time, the activation energy decreases down to anomalously low values, which is related to structural changes in the powder mixtures. A method was proposed to process thermograms of the synthesis in the thermal explosion mode and was used to study the kinetic function structure and its parameters in the system. The numerical processing of the experimental data shows that the kinetic function most adequately corresponds to the law of homogeneous kinetics of phase formation with the reaction order close to unity.

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► The activation energy decreases with an increase of milling time.
► With milling time, the ignition temperature and the maximum developed temperature decrease monotonically.
► Decrease ceases after 120 s under the centrifugal acceleration of balls 40 g.
► The calculated activation energy is equal to E = 9.2 kJ mol−1.