Establishing the interface layer on the aluminum surface through the self-assembly of tannic acid (TA): Improving the ignition and combustion properties of aluminum

• Al@TA-Fe composite with core-shell structure are prepared. • The TA-Fe interface layer can promote the ignition of aluminum. • The TA-Fe layer can inhibit the agglomeration of aluminum. • The TA-Fe layer can improve the corrosion resistance of aluminum. Aluminum powder is widely used in the field of propellants and explosives due to its high energy density. However, the dense oxide film on its surface will hinder the combustion of aluminum powder. Herein, Al@TA-Fe with core-shell structure was prepared by self-assembly of tannic acid (TA) and Fe(III) ion on the surface of aluminum, and was characterized by scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and thermogravimetry-differential scanning calorimetry (TG-DSC). The results show that the TA-Fe interface layer in Al@TA-Fe can effectively promote the ignition of aluminum powder, which can make the aluminum powder be ignited at the temperature far below the melting point of aluminum. Meanwhile, the carbides formed by the decomposition of tannic acid are beneficial to the cracking of the alumina on the surface of the aluminum powder, which can promote the internal aluminum to participate in the reaction and improve the reaction efficiency of aluminum. The TA-Fe layer can inhibit the agglomeration of molten aluminum during the combustion of aluminum and can effectively improve the corrosion resistance of aluminum powder. The iron ions in the TA-Fe interface layer can successfully catalyze the thermal decomposition process of ammonium perchlorate (AP). In addition, Al@TA-Fe can effectively increase the burning rate of the propellant compared with pure aluminum powder.