Critical changes in the ignition and combustion characteristics of aged titanium-based initiators

Abstract Titanium hydride potassium perchlorate (THPP), which is one of the most commonly utilized pyrotechnic initiators, can fail or deviate from the desired performance when subjected to aging. The aging process is known to change its composition as well as its thermochemical kinetics; however, the variation in the performance of THPP in terms of its combustion behavior has not been addressed. This experimental paper reports new correlations between the ignition and combustion characteristics of THPP. A thermal analysis, along with morphological observations, conducted on aged samples revealed that aging caused progressive oxidation of the fuels and subsequent decomposition of the oxidants. The reaction kinetics extracted using the isoconversional method pointed to a decrease in the activation energy due to thermal aging while the opposite was noted in the case of hygrothermal aging. In particular, an increase in the activation energy limited the range of ignition temperature and decreased the reactivity, thereby increasing both the ignition delay time and burn time. Such altered characteristics due to aging could lead to an inconsistent performance of the pyrotechnic initiators.