Influence of extrinsic induced tensile stress on the self-propagating high-temperature synthesis of nanosized Al/Ni multilayers

Reactive multilayer systems consisting of alternating nanoscale Al and Ni layers are applicable in joining, various pyrotechnic applications and thermal batteries. Since diffusion based high-temperature synthesis occurs without the presence of air, efforts have focused on investigating the understanding of the fundamental reaction processes and characteristics. The aim of this study is to expose the reactive multilayers to extrinsic induced tensile stress so that the self-propagating synthesis can proceed under these conditions. Further, the properties during and after the reaction will be investigated. Multilayers deposited by sputtering on Kapton (R) substrates with different bilayer- and total thicknesses as well as commercial Nanofoils (R) with thicknesses of 40 mu m and 60 mu m were used as samples. The investigations focused on the propagation velocity measured with a high-speed camera, the temperature regime determined with a high-speed pyrometer, and the formed phases after the synthesis examined via X-ray diffraction. The gained results of this study reveal important insights for the application of the reactive Al/Ni multilayer system in terms of stability or reliability related to propagation front velocity, maximum temperature and formed phases under induced external tensile stresses.

Automated summary

The aim of this study is to investigate the reaction processes and characteristics of reactive multilayer systems under extrinsic induced tensile stress. The properties during and after the reaction, including propagation velocity, temperature regime, and formed phases, were studied using different samples. The results provide important insights for the stability and reliability of the reactive Al/Ni multilayer system under external tensile stresses.