Comparative Multiscale Thermal Analysis of Coated Aluminum Hydride

To enhance the stability of aluminum hydride (AlH ₃ ) against external energy stimuli, this study modified its surface using six coating agents from three categories. Successful coating was confirmed by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD). An evaluation system for multi-scale thermal stability was established to simulate thermal stimuli across different time scales and energy intensities: vacuum outgassing tests and differential scanning calorimetry (DSC) were employed to assess the response to long-term weak thermal stimulation and programmed strong thermal stimulation, respectively, while electrostatic spark sensitivity tests evaluated safety under instantaneous extreme thermal stimulation. Results showed that the graphene oxide (GO) coating exhibited superior synergistic performance, significantly improving long-term hydrogen inhibition, increasing decomposition activation energy by 12.1 kJ/mol, and significantly enhanced the 50% ignition energy (\(\:{E}_{50}\)) by 229.9%. In contrast, coatings like glycidyl azide polymer (GAP) and Stearic acid (SA) presented potential risks due to catalytic effects or worsened sensitivity, underscoring the necessity of comprehensive evaluation. Therefore, GO is identified as the most promising coating for achieving stable AlH ₃ in energetic applications. This study provides systematic experimental and theoretical support for developing coated AlH ₃ , thereby facilitating its practical and safe utilization in solid propellant formulations.