To solve the problems associated with micron-sized aluminum (Al), including sintering, agglomeration, and slag deposition during the combustion of aluminized propellants, aluminum–lithium (Al-Li) alloy, prepared by introducing a small amount of Li (1.0 wt.%) into Al, was used in place of Al. Then, the ignition and combustion characteristics of single micron-sized Al-Li alloy particles were investigated in detail using a self-built experimental apparatus and multiple characterization methods. The ignition probability, ignition delay time, flame propagation rate, burn time, combustion temperature, flame radiation spectra, and microexplosion characteristics were obtained. The TG-DSC results demonstrated that, as compared to the counterpart Al, the Al-Li alloy had a lower ignition temperature. The emission lines of AlO revealed the gas-phase combustion of the Al-Li alloy, and thus the Al-Li alloy exhibited a mixed combustion mode, including surface combustion and gas-phase combustion. Moreover, during combustion, a microexplosion occurred, which increased the combustion rate and reduced the burn lifetime. The ambient pressure had a significant effect on the ignition and combustion characteristics of the Al-Li alloy, and the ignition delay time and burn time exponentially decreased as the ambient pressure enhanced. The combustion temperature of the Al-Li alloy at atmospheric pressure was slightly higher than those at elevated pressures. The Al-Li alloy burned in N2, but no microexplosion was observed. Finally, the ignition and combustion mechanism of the Al-Li alloy in air was demonstrated by combining SEM, EDS, and XRD analyses of the material and residues. The results suggest that the addition of Li promoted the combustion performance of Al by changing the surface structure of the oxide film and the combustion mode.

中文翻译：

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高压空气/N2 中单微米级铝锂合金颗粒的激光诱导点火和燃烧

为了解决与微米级铝 (Al) 相关的问题，包括含铝推进剂燃烧过程中的烧结、团聚和熔渣沉积，通过引入少量 Li (1.0 wt) 制备铝锂 (Al-Li) 合金.%）转化为 Al，用于代替 Al。然后，利用自制的实验装置和多种表征方法，详细研究了单微米级铝锂合金颗粒的着火和燃烧特性。获得了着火概率、着火延迟时间、火焰传播速率、燃烧时间、燃烧温度、火焰辐射光谱和微爆特性。TG-DSC 结果表明，与对应的 Al 相比，Al-Li 合金具有较低的着火温度。Al2O的发射谱线揭示了Al-Li合金的气相燃烧，因此Al-Li合金表现出混合燃烧模式，包括表面燃烧和气相燃烧。此外，在燃烧过程中，发生了微爆，增加了燃烧速率，缩短了燃烧寿命。环境压力对铝锂合金的着火燃烧特性有显着影响，随着环境压力的升高，着火延迟时间和燃烧时间呈指数下降。常压下铝锂合金的燃烧温度略高于高压下的燃烧温度。Al-Li 合金在 N2 中燃烧，但没有观察到微爆炸。最后结合SEM、EDS、材料和残留物的 XRD 分析。结果表明，Li的加入通过改变氧化膜的表面结构和燃烧方式来提高Al的燃烧性能。