A facile and effective strategy for modifying combustion of Zr/KClO₄ via adding Si

As a commonly applied ignition composition, Zr/KClO₄ has attracted various interests and plenty of efforts have been made to improve the combustion performance. In this study, Si nanoparticles were incorporated into Zr/KClO₄ by sonication. Around 2.5× peak pressure and 9.2× reactivity were achieved by Si/50%Zr/KClO₄ when compared to Zr/KClO₄. In addition, the peak pressure and pressurization rate of Si/Zr/KClO₄ ternary systems are all superior to ones of both Zr/KClO₄ and Si/KClO₄ binary systems. The synergetic effect of Si/Zr/KClO₄ is a combination of shorter ignition delay of Zr/KClO₄ and more gas production of Si/KClO₄, which is also reflected on the higher flame propagation rate of Si/Zr-based thermites than composites with pure Si or Zr as the fuel. Meanwhile, the heat release during the redox reaction has been measured. The results show ∼700–1000 J/g higher energy release than Zr/KClO₄, and higher combustion efficiency can be attained by ternary systems than binary ones. Thus, adding Si powders is an effective way to improve the energetic behavior of Zr/KClO₄ ignition composition, and Si/Zr/KClO₄ ternary composites can be a promising candidate for application in pyrotechnics.