Disodium terephthalate as a multifunctional additive for simultaneous enhancing the energy release performance and weakening the water reactivity of aluminum

Abstract

In this study, disodium terephthalate (Na2TP) has been successfully introduced as a novel multifunctional additive for simultaneous enhancing the energy release performance and weakening the water reactivity of micro-aluminum (μ-Al). Seven μ-Al/Na2TP composites with different contents of Na2TP (R-100 to R-700) and four comparison samples have been prepared to investigate the thermochemical behaviors, combustion performances and water reactivity. Importantly, structure characterizations as well as kinetic parameters (e.g., Ea, ΔS‡) have been performed to reveal the impacts of Na2TP on μ-Al oxidation. Moreover, incorporating Na2TP into μ-Al shows the enhancement of energy release, with R-400 exhibiting the highest heat release (4970 J/g) in the main oxidation stage, compared to μ-Al (1696 J/g). Interestingly, μ-Al shows an increased Ea while R-400 exhibits a decreased Ea as the oxidation proceeds. The decomposition of Na2TP generates both heat and CO2 gases, which are beneficial for destroying alumina shell and increasing oxidation kinetics, in consistent with higher positive ΔS‡ value, rougher surface, and higher surface O content for oxidation of R-400 compared to μ-Al. As a result, the enhanced combustion performances of higher peak pressure, pressurization rate and characteristic shock velocity as well as brighter/larger flame images have been achieved by μ-Al/Na2TP composites. On the other hand, water reactivity of μ-Al has been significantly suppressed by introducing Na2TP in terms of the 85.4 % decrease in heat release, elevated Ea, and alteration of reaction mechanism. Consequently, taking organic Na2TP as a multifunctional additive, two birds of enhancing the energy release and weakening the water reactivity is harvested, showing great potentials in improving the performances of metal-based energy systems.