The thermal explosion synthesis of AlNi monitored by neutron thermodiffractometry

Abstract

The synthesis of AlNi from thermally activated equimolar powder mixtures of aluminium and nickel was monitored in situ and acquired diffraction patterns every 2 s or less. The analysis of diffraction patterns ( λ = 1.3112 Å ) permitted establishment of its kinetics, which could be modeled according to an equation expressed as kt = [ α / ( 1 - α ) ] 3 / 2 . From 1530 to ≈ 600 ° C an activation energy of 9 ± 2 kJ mol −1 was estimated. Also, the crystallite size evolution on cooling was established to vary from ≈ 14 nm at 1530 °C to ≈ 28 nm at 180 °C. Finally, the reaction was found to occur through the melting of aluminium and the subsequent dissolving of nickel to form the polycrystalline single-phase product, AlNi.