Synergistic effect of AP/KP composite oxidizers prepared by electrostatic spraying and promotion of aluminum combustion performance

In order to solve the problems of low effective oxygen content, low density and high mechanical sensibility of ammonium perchlorate (AP) for propellant, potassium perchlorate (KP), which has a higher density and greater effective oxygen content, was introduced. An AP/KP composite oxidizer was prepared using electrostatic spraying. The morphology, structure, thermal properties, safety, and combustion performance of the samples were characterized using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), and a quadruple coupling technique (TG-DSC-FTIR-MS). Comparative studies were performed with raw materials and physically mixed samples. The results indicate that the crystal structures of AP and KP remained unchanged in the composite oxidizers prepared using different methods. The electrostatic spray samples exhibited significantly improved safety compared to raw AP and physically mixed samples, with friction sensitivity reduced by 36% and 16%, respectively. Thermal analysis revealed that the electrostatic spray samples significantly enhanced the high-temperature decomposition of AP and KP, with decomposition peaks reduced by 49.15 °C and 9.67 °C, respectively. Additionally, the electrostatic spray method significantly reduced the activation energy of KP's thermal decomposition from 448.32 to 440.62 kJ·mol^{- 1} to 222.80-226.11 kJ·mol^{- 1}. Compared to raw and physically mixed samples, the electrostatic spraying method reduced the ignition delay time of the composite oxidizer, increased the aluminum powder combustion rate, and enabled complete combustion of the Al powder. The electrostatic spraying method, with its adjustable process parameters and controllable sample morphology, enhances the overall performance of the composite oxidizer.