Macrokinetics of thermal explosion in a 3Ni-Al system mechanically activated in a low-energy mill

Abstract

Two-step mechanosynthesis in the 3Ni - Al system has been investigated by experimental and theoretical methods using the developed macrokinetic theory of mechanochemical synthesis (MS). The first step included the grinding and mechanical activation (MA) of the starting reaction mixture in the mill, and the second step included the explosive synthesis of the Ni3Al intermetallic compound outside the mill. The effect of mechanical pre-treatment on the temperature-time parameters of the synthesis of the Ni3Al intermetallic compound was found. The phase composition of the activated mixture of nickel, aluminum, and synthesized products was characterized by X-ray diffraction. Preliminary low-energy mechanical activation (LEMA) of the mixture in a laboratory mill eliminates the negative phenomena associated with the grinding and formation of intermediate phases. Kinetic and thermophysical constants characterizing the two-step MS were determined using the inverse problem. The contribution of mechanical activation factors to the acceleration of Ni3Al synthesis was quantitatively evaluated.