Study of chemical reactions sequence and calculation of self-propagating front velocity in multilayer Al-Ni thermite structures

In recent years multilayer structures replaced traditional powder thermite mixtures and opened up new possibilities for nano- and micro-scale surfaces, materials and devices joining processes. This paper presents the results of experimental studies of the thermal wave propagation velocity in multilayered thermite materials. For experimental studies Al-Ni based multilayer structures were formed on various substrates using magnetron sputtering. Evaluation of the wave propagation rate was performed using high-speed video camera. For freestanding foils propagation rate was about 4 m/s, and for a multilayer structure on ABS plastic surface about 2 m/s. In addition, mathematical modeling of the heat release process allowed to theoretically estimate the speed of a chemical reaction front propagation. For example, the calculated value of the front propagation rate for structure on monocrystalline Si with 60 nm aluminium and a 15 nm nickel layers was about 0,52 m/s.