Microstructures and Reaction Properties of Ti/Ni, Ti/Al and Ni/Al Multilayer Films

摘要

Reactive multilayer thin films are well-defined heterogeneous nanostructured energetic materials which can release chemical energy through a self-sustainable reaction. They have attracted intense interests due to potential applications in diverse fields such as joining, igniters, and high energy density power sources. In this paper, Ti/Ni, Ti/Al and Ni/Al multilayer films were prepared by magnetron sputtering. The reaction kinetics, microstructure and phase variation of these free-standing films are comparatively investigated. During slow heat reaction, the reaction products of reactive multilayer Ti/Ni nanofoils change from B2-TiNi austenite phase into TiNisub3/sub, illustrating an evolution of the phase transformation during reaction. These intermediate phases are also identified by slow heating and quenching. The fast speed imaging exhibits that the front speed is 0.47m/s, 0.8m/s and 3m/s respectively for as-deposited Ti/Ni, Ti/Al, and Ni/Al films. Differential thermal analysis yields that the corresponding releasing heat is 551.44 J/g, 434.18 J/g, and 562.5 J/g for these three composites. The theoretical minimum multilayer thickness for melting a tin solder layer has been calculated on the base of these characterizations, which proved the application potential of joining using the as-deposited film.