Aluminum powder with a high specific impulse, high stability, and adjustable reactivity is widely used in the aerospace field. However, most current research focuses on the single sized nano-(n) or micro (mu)aluminum (Al) powders. The synergistic effect between multi-scale Al powders was ignored. In this paper, firstly, the n-mu Al powders were modified by polydopamine (PDA) as the interface layer, then they were further modified and encapsulated by polytetrafluoroethylene (PTFE) and ammonium perchlorate (AP). The effects of PDA interface structure and fluoride compounds on the combustion performance and agglomeration of Al were studied in the lean oxygen environment. The results show that the ration methods of PDA-modified nAl mixed with mu Al yields satisfactory results. The thickness of PDA interface layer on the surface of nAl powder is positively associated with the concentration of mixed solution of dopamine hydrochloride. The PDA interface layer not only regulates the thermal reactivity of modified sample by reducing the decomposition temperature and rate of AP, but also has a significant impact on the flame diffusion and combustion intensity. The synergistic effect of PDA interface layer, PTFE, and n-mu Al powders can significantly inhibit the agglomeration of Al particles during combustion. (c) 2022 The Combustion Institute. Published by Elsevier Inc. All rights reserved.
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