High-power nanosecond pulse laser ignition of Al/Ni energetic composites at high heating rate

In this work, Al/Ni energetic composite powders were ignited by the high-power pulse laser in high heating rate of ∼ 10¹²K/s within nanoseconds. A custom-built experimental setup, integrating a high-speed schlieren system and a LIBS module, was utilized to investigate laser-induced reactions spanning from microseconds to milliseconds. The 2Al:3Ni composite shows the fastest ascent rate and the highest peak intensity of AlO emission in time-resolved spectral analysis. And the intense exothermic chemical reactions within the plasma also results its fastest expansion of laser-induced shockwave. The 1Al:2Ni exhibits the highest particle ejection velocity, surpassing that of the 1Al:1Ni by 50 %. Laser-induced self-sustaining reaction is observed in the 1Al:1Ni and 2Al:3Ni samples, with the latter showing a more rapid transition from laser-induced plasma to self-sustaining reaction. Morphological and compositional characterization of the ablated crater has proved that the Ni particles melt and interact with surrounding air initially during the laser-induced self-sustaining reaction, while the exothermic Al/Ni combination reaction further enhances rapid combustion in the early stages. Moreover, 2Al:3Ni presents the best early-stage combustion performance in the metalized CL-20. This research offers an effective methodology for assessing the performance of Al-based energetic materials under simulated explosion conditions and provides insights into formula optimization.