Catalytic activity of K2Ba[Ni(NO2)6] on the thermolysis and laser ignition of CL-20, FOX-7 and TKX-50

Abstract Hexanitro complex K2Ba[Ni(NO2)6] was prepared via the co-precipitation method, and its composition and morphology were characterized by XRD, SEM, XPS and FT-IR techniques. The catalytic performances of K2Ba[Ni(NO2)6] for CL-20, FOX-7 and TKX-50 thermolysis were also discussed and studied by using DSC and TG-DTG-MS. After K2Ba[Ni(NO2)6] were mixed with CL-20, the activation energy (Ea) of thermolysis reaction was increased, while the heat release was greatly improved, and the transformation from NH3 to NO occurred. It is attributed to that the decomposition products of K2Ba[Ni(NO2)6] have strong effects on the oxidation of the radicals and the electrons transfer. Besides, the thermolysis Ea of FOX-7 by addition of the K2Ba[Ni(NO2)6] was increased by 81.03 kJ mol−1, and the heat release was greatly increased. In addition to that the two-step separate thermolysis processes of pure FOX-7 was almost replaced by a one-step exothermic reaction for the FOX-7/K2Ba[Ni(NO2)6] mixture, which was due to that Ni2+ cations could effectively increase the activity of amino groups in the FOX-7 thermolysis process. Finally, K2Ba[Ni(NO2)6] scarcely has the thermolysis catalytic activity of TKX-50 owing to the influence of metal cations on the decomposition of the hydroxylamine. Furtherly, the characteristics of ignition and flame propagation on the three energetic mixtures were strongly correlated to their thermolysis pathway and mechanism. The comparative study on the effects of K2Ba[Ni(NO2)6] to the CL-20, FOX-7 and TKX-50 thermolysis and ignition showed that the hexanitro complex has great significance on promoting the heat release efficiency of solid propellants for future study.