Influence of Environment on Self-Propagating Reactions in Al/Ni Multilayer Foils

Influence of Environment on Self-Propagating Reactions in Al/Ni Multilayer Foils<br/>Deepshikha Shekhawat ^1*, Mostafa Baloochi ¹, Vishal Amarbhai Raheja ¹, Joachim Döll ², Sebastian Matthes ³ , Marcus Glaser ⁴ , Jörg Pezoldt ¹* <br/> <br/>¹FG Nanotechnologie, Institut für Mikro- und Nanelektronik and Institut für Mikro- und Nanotechnologien MacroNano^â and Institut für Werkstofftechnik, TU Ilmenau, Postfach 100565, 98684 Ilmenau, Germany; [email protected] (M.B.); [email protected] (V.A.B.)<br/>²Zentrum für Mikro- und Nanotechnologien, TU Ilmenau, Gustav-Kirchhoff-Straße 7, 98693 Ilmenau, Germany; [email protected] (J.D.)<br/>³FG Werkstoffe der Elektrotechnik, Institut für Werkstofftechnik, Institut für Mikro- und Nanotechnologien MacroNano®, TU Ilmenau, Gustav-Kirchhoff-Strasse 5, 98693 Ilmenau, Germany; [email protected] (S.M.)<br/>⁴ FG Fertigungstechnik, Institut für Mikro- und Nanotechnologien MacroNano®, TU Ilmenau, Postfach 100565, 98684 Ilmenau, Germany; [email protected] (M.G.)<br/>* Correspondence: [email protected] (D.S.); [email protected] (J.P.)<br/> <br/><b>Abstract:</b> Reactive multilayer systems signify as an energetic materials potentially for extremely short thermal treatment compared to standard reactive techniques. As there are several factors leading the reaction front velocity, released energy, microstructural and morphological changes are of great interest. In the current investigation, alternative Al and Ni layers depositated by magnetron sputtering techniquie where Al is starting layer with a 1:1 atomic ratio of Al and Ni onto different substrate. In order to elucidate the influence of different enviormental condition, a two-dimensional numerical model was developed to study convective heat loss and thermal properties on the self-propagating reaction in Al/Ni multilayer foils. Reaction heat of the fabricated foils were determined by Differential Scanning Calorimetry (DSC). Self-propagating reaction was introduced on the surface of the foils by an electrical spark. The reaction front velocity was noted with a high speed camera. Activation energy is set with these velocity data to modify the numerical model. Temperature of reaction front of the self-propagating reaction was calculated and compared with the obtained temperature by time-resolved pyrometer measurements. X-ray diffraction investigation of reacted multilayers confirmed that all reactants reacted and formed AlNi phase as a finale phase. Finally, it is predicted that (1) increasing thermal conductivity of the suroundings can increases the transfer of the reaction front; (2) effect of heat convection losses on reaction properties are insignificant, e.g., the foils can maintain their properties in liquid environment.<br/> <br/><b>Keywords:</b> reactive multilayers; self-sustained reaction; nickel; aluminum; propagation velocity; phase transformation; magnetron sputtering