THE INFLUENCE OF ACCELERATED AGING ON MAGNESIUM/PTFE/FPM DECOY FLARES

Magnesium/PTFE/FPM decoy flares, also named conventional flares, were designed in order to protect combat aircraft from the threat caused by infrared-guided missiles. Adverse storage or transport conditions may cause reactions that deteriorates chemical properties of the conventional flares, causing the aging and compromising its performance. The aim of this article was to characterize the influence of accelerated aging on conventional flares. The study was performed with the latest lot of conventional flares from Brazilian Air Force, subjected to 50 days exposure in a climatic chamber at 76 degrees C and 62% RH. Upon completion of the accelerated aging process, samples of aged conventional flares were compared with unaged material. Qualitative determination of chemical species present was carried out using the techniques FT-IR and SEM/EDS. Magnesium hydroxide, the main product of aging process and primary aging indicator on conventional flares performance, was determined using thermogravimetric analysis and the amount was correlated with results of the experimental techniques Density Determination, Calorimetry and Vacuum Stability Test. Formation of additional magnesium hydroxide mass, that increased 100% during the aging process, caused the passivation of magnesium, compromising the combustion process and making the composition less energy efficient, as verified in the results of the calorimetric tests.