The ignition and combustion performances of core-shell Al-based intermetallic nanocomposites surrounded with AP

In this paper, three nanocomposite fuels (Al/TMs@AP) including Al/Co@AP, Al/Ni@AP and Al/Ti@AP have been fabricated by a spray-drying technique. Their morphology, heat of reaction, ignition and combustion performances, as well as their condensed combustion products (CCPs) have been comprehensively investigated. The results suggested that the core-shell structured Al/TMs@AP has lower ignition delay and better combustion performances comparing to the corresponding mechanically mixed ones. The promoted thermal reactivity could be attributed to resulted intimate reactants contacts with shortened heat and mass transfer distance. Furthermore, the reactivity of Ti is higher than that of Co and Ni, so that a much more violent chemical reaction occurred for the Ti-containing composites, and thereby the combustion wave temperature was increased to 2136.6 °C and the particle size of the corresponding CCPs was reduced to as low as 170 nm. Moreover, the compositions of CCPs for Al/Ti/AP and Al/Ti@AP are quite different. The typical CCPs phases for Al/TMs@AP are dominated with Al_xTM_yO_z and Al₅O₆N, whereas the CCPs of the other samples are dominated with transition metals oxides such as Co₃O₄, NiO and TiO₂ depending on the type of transition metals involved.