Investigation of the thermal decomposition of magnesium-sodium nitrate pyrotechnic composition (SR-524) and the effect of accelerated aging

The aging behavior of the pyrotechnics is influenced by the storage atmosphere and more specifically on the temperature and humidity levels. The investigated composition SR 524 is a military pyrotechnic composition that is used as a tracer. The accelerated aging of the SR 524 composition has been carried out at a temperature of 70 °C and relative humidity of 70 percent. The results indicate that there is significant change in the thermal behavior, kinetic parameters and the morphology of the aged composition. The decomposition temperature and the activation energy were found to be lowered in the aged composition. The activation energy of the aged composition decreased nearly 57 percent. SEM micrographs of the aged composition revealed the development of micro cracks as a result of accelerated aging. XRD spectra of the aged composition showed the presence of magnesium hydroxide indicating the reaction between magnesium and water vapors present in the highly humid atmosphere.