A shell passivation strategy for micro-scale aluminum particles and power generation applications

IF 4.9 2区化学 Q2 CHEMISTRY, PHYSICAL

Colloids and Surfaces A: Physicochemical and Engineering Aspects Pub Date : 2025-05-14 DOI:10.1016/j.colsurfa.2025.137200

Mahmuda Ishrat Malek, Cason Jones, Wyatt Benson, Michelle L. Pantoya

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引用次数: 0

Abstract

Aluminum (Al) particles are widely used as solid fuels in energy generating applications such as rocket propellants, batteries, and powering MEMS devices. The particles are naturally a core-shell composite of aluminum-alumina (Al₂O₃). The passivation shell is a strong barrier to oxygen diffusion and thus limits power generation potential. Recent studies on nano-aluminum (nAl) particles replaced the Al₂O₃ shell with an oxygen-rich, halogen-based shell composed of [Al(H₂O)₆](IO₃)₃(HIO₃)₂ called aluminum iodate hexahydrate (AIH). The abundance of oxidizing species in molecular scale proximity to the Al core, and the relatively low decomposition energy of AIH provided the conditions necessary to increase power from the nAl reactions. However, AIH passivated nAl was highly ignition sensitive and unsafe to handle. Micron-sized aluminum (µAl) particles are less ignition sensitive than nAl particles and are a suitable alternative for extending nAl-shell modification approaches. This study used µAl particles to synthesize a controlled concentration of AIH shell (µAl@AIH). The precipitation reactions required for shell synthesis examined three key variables to control AIH concentration: H₂O to I₂O₅ solution ratio, solution temperature, and time in solution. Thermal analysis of the µAl@AIH particles confirmed AIH dehydration and decomposition followed by core oxidation. The µAl@AIH powder showed up to 92 % increase in apparent oxidation efficiency compared to standard Al indicating the AIH shell provides increased oxygen accessibility to the core. Accelerated aging studies revealed physical and chemical transformation of AIH, but the new shell structure resulted in a further 1992 % increased apparent oxidation efficiency than standard Al. The apparent activation energy for the unaged and aged µAl@AIH powder is 16–34 % lower in equilibrium and non-equilibrium conditions compared to standard Al. The results shown here pave the way for the development of new solid fuels with tremendous power generation capabilities compared to the yesteryear particles plagued by a nearly impenetrable native oxidation passivation layer crippling the speed of energy release.

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微尺度铝粒子壳钝化策略及发电应用

铝（Al）颗粒被广泛用作固体燃料，用于能源产生应用，如火箭推进剂，电池和为MEMS设备供电。这些颗粒是天然的铝-氧化铝（Al2O3）的核-壳复合材料。钝化壳是氧气扩散的强大屏障，因此限制了发电潜力。最近对纳米铝（nAl）颗粒的研究用一种由[Al(H2O)6](IO3)3(HIO3)2组成的富氧卤素基壳层取代了Al2O3壳层，称为六水碘酸铝（AIH）。在靠近Al核心的分子尺度上，氧化物质的丰度和AIH相对较低的分解能为nAl反应的功率增加提供了必要的条件。然而，AIH钝化的nAl具有高度的着火敏感性，处理起来不安全。微米尺寸的铝（µAl）颗粒比nAl颗粒更不敏感，是扩展nAl壳改性方法的合适替代方案。本研究使用µAl颗粒合成了控制浓度的AIH壳（µAl@AIH）。壳合成所需的沉淀反应考察了控制AIH浓度的三个关键变量：H2O / I2O5溶液比、溶液温度和溶液时间。µAl@AIH颗粒的热分析证实了AIH脱水和分解，然后是核心氧化。与标准Al相比，μ Al@AIH粉末的表观氧化效率提高了92 %，这表明AIH外壳增加了核心的氧气可及性。加速老化研究揭示了AIH的物理和化学转变，与标准Al相比，未老化和老化的μ Al@AIH粉末在平衡和非平衡条件下的表观活化能比标准Al低16-34 %。与过去几乎无法穿透的天然氧化钝化层所影响的颗粒相比，这里显示的结果为开发具有巨大发电能力的新型固体燃料铺平了道路削弱能量释放的速度。

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来源期刊

Colloids and Surfaces A: Physicochemical and Engineering Aspects 化学-物理化学

CiteScore

8.70

自引率

9.60%

发文量

2421

审稿时长

56 days

期刊介绍： Colloids and Surfaces A: Physicochemical and Engineering Aspects is an international journal devoted to the science underlying applications of colloids and interfacial phenomena. The journal aims at publishing high quality research papers featuring new materials or new insights into the role of colloid and interface science in (for example) food, energy, minerals processing, pharmaceuticals or the environment.