Effect of stearic acid coating on the flame propagation and reaction mechanism of AlH3

AlH 3 is considered to be the most promising high-energy additive and stearic acid (SA) is a common passivation coating material to enhance stability. To explore the effect of coating of SA on AlH 3 , flame propagation and reaction mechanisms are compared through ignition experiments and ReaxFF molecular dynamics, respectively. The flame propagation of AlH 3 /SA slowed down for ∼20 ms and the flame duration is longer for ∼50 ms, indicating that the combustion intensity is reduced. The combustion reaction of AlH 3 is initiated through the release of •H by H-Al breaking and further oxidizing to form H 2 O and Al-O clusters. The presence of SA results in more O and C atoms contained in the system and more reaction paths. The addition of C atoms and O atoms makes the maximum cluster molecular weight of AlH 3 /SA increase by 0.1 × 10^4 than AlH 3 . The results of flame propagation and reaction mechanisms verify that the stability of AlH 3 is improved by the coating of SA.