Inhibiting aluminum agglomeration and enhancing combustion in composite propellants via perfluoropolyether

Aluminum powder is widely incorporated into solid propellants to boost their specific impulse, yet its coalescence into large agglomerates during combustion impairs ballistic performance by reducing combustion efficiency, increasing two-phase flow losses, and degrading specific impulse. Perfluoropolyether (PFPE) exhibits promising potential in suppressing aluminum agglomeration, but its functional mechanism within full-component propellant formulations remains unclear. This study systematically investigates the effects of PFPE with varying contents (0–3%) on the combustion behavior of Al/AP/HMX-based composite propellants. Thermal analysis results demonstrate that PFPE can promote the decomposition of aoxidizers, lowering the peak decomposition temperature and increasing the mass loss rate of the propellant system. In-situ microscopy observations reveal that the addition of 1.5% PFPE shortens the residence time of aluminum particles on the burning surface, effectively inhibiting the formation of large aluminum agglomerates. Laser ignition tests under atmospheric pressure and high-pressure combustion tests at 3 MPa show that 1.5% PFPE reduces the ignition delay of the propellant to 31 ms and increases the burning rate to 4.54 mm/s. Characterization of condensed combustion products collected at 7 MPa confirms that the propellant formulation with 1.5% PFPE generates smaller aluminum agglomerates and elevates the combustion efficiency to 84.63%. However, a high PFPE content (3%) dilutes the energy density of the propellant and deteriorates its combustion performance. These results indicate that the optimal PFPE content can accelerate oxidizer decomposition and disrupt the inert layer on aluminum particles through fluorination, thereby achieving effective suppression of aluminum agglomeration and enhancement of combustion performance in composite propellants.