Article Dans Une Revue Fuel Année : 2026

Influence of Al as an alloying element on the combustion process of micron-sized iron particles

Résumé

While iron powder has been identified as a promising sustainable energy carrier, the influence of alloying elements on the combustion process is still not well understood. In particular, even though pure Al combustion has been extensively studied, the influence of Al as an alloying element has never been investigated before. The objective of this work is to understand how the presence of Al at varying concentrations impacts the combustion regime of Fe particles. Therefore, we produced and burned three Fe-Al powders with varying Al contents (5, 9, and 20 wt.%), using both single-particle and multi-particle combustion setups, allowing for both in situ visualization and ex situ microstructural analysis. In the multi-particle burner, the combustion products showed a limited combustion efficiency (1%) when increasing the initial Al content to 9 and 20 wt.%, compared to 86.5% for 5 wt.% initial Al content. Microstructural analysis of non-ignited particles revealed the presence of an Al2O3 layer, suggesting hindering internal diffusion. In the single-particle burner, particles successfully ignited and exhibited liquid-phase combustion with complex oxidation behavior, including oxide lobe formation, heterogeneous surface oxidation, and jetting and spinning behavior due to asymmetric evaporation-driven flows. Despite their low combustion efficiency, post-combustion microstructure analysis of Fe-9Al and Fe-20Al powders revealed that ignited particles fully oxidize in the liquid state and are constituted of a bi-phasic dendritic structure with Al-enriched and Fe-enriched dendrites. While combusted Fe-5Al particles are constituted of a homogeneous magnetite phase containing Al in solid solution. This study highlights the importance of Al alloying content on the combustion behavior of micron-sized Fe particles, in particular on their combustion efficiency, evaporation dynamics, or the microstructural and chemical distribution of the combustion products.

Dates et versions

hal-05571805 , version 1 (30-03-2026)

Identifiants

Citer

Z. Bruyr, L. Ahmad, L. Choisez, F. Halter, F. Contino. Influence of Al as an alloying element on the combustion process of micron-sized iron particles. Fuel, 2026, 422, pp.139083. ⟨10.1016/j.fuel.2026.139083⟩. ⟨hal-05571805⟩
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