Mechanism of Chemically Induced Structural Evolution of Lead Azide under Hygrothermal Condition

Aging behavior of pyrotechnic agents is a serious threat to the reliability of the practical application of pyrotechnic products, while multiple environmental factors make it challenging to characterize the aging mechanism of pyrotechnic agents. This paper explored the aging process of LA in four hygrothermal environments with morphology and structure analysis techniques. LA aging underwent three stages: rapid surface reaction with H₂O and CO₂, interior hydrolysis by H₂O, and CO₂ reaction with lead oxides. The cavity structures formed during LA’s structural evolution reduced its energy density, causing increased energy dissipation under mechanical stimuli and preventing ignition. Further, reactions formed by inert lead compounds resisted electrostatic ignition, leading to agent failure. This comprehensive study provided a solid foundation for understanding the aging behavior of LA in multistress environments, offering valuable insights into its safe storage and handling.