Investigation of Al/SrO₂/MgSt and Si/CaO₂/MgSt Delay Pellets and Parameters Influencing the Burning Rate As Well As Thermal Aging Effects on Their Burning Properties

ABSTRACT Toxic and environmentally harmful components of pyrotechnic compositions require to be substituted with alternative substances. Therefore, the subject of this work was the burning rate investigation of the Al/SrO 2 and Si/CaO 2 pyrotechnic delay compositions. The delay elements were prepared by pressing the compositions into pellets and transferring them into delay tubes. However, the Al/SrO 2 pellets were also placed into the delay tube and post‐pressed to determine if any differences in the burning rate were measurable. The dependency of the burning rate in relation to the pellet diameter, binder content, delay tube material, and artificial aging of the compositions was investigated. Further, the impact of the aging as well as of the binder content on the ignition temperature of the compositions was determined. The used silicon powders were characterized by means of Raman spectroscopy, particle size analysis, and BET surface area analysis. Raman spectroscopy was also used to investigate differences between the freshly prepared and artificially aged pyrotechnic compositions. The investigation of friction and impact sensitivity of the compositions, with and without use of the binder, resulted in the classification of both compositions as insensitive. In addition, the mechanical pellet stability in dependency of the binder content was determined, which increased with the binder content.