Influence of various binders and oxidizers on the spectral emission of pyro-organic flares

IR decoy flares proved as an effective measure to protect military platforms as well as civilian airplanes. Recent missiles equipped with modern seeker technology are able to distinguish between target and decoy flares evaluating spectroscopic emission. Therefore, new spectral flares have to be adapted to the thermal and spectral emissivity of the platform to be protected. One approach to achieve this goal consists in the application of a pyro-organic flare by combining hydrocarbon combustion to settle spectral requirements and pyrotechnic mixtures to increase the radiation intensity of the band signature. In recent developments, HTPB bonded samples including AP as oxidizer and various pyrotechnical mixtures were prepared and tested with regard to potential use as a spectral flare. In the present study, Al/CuO-thermite mixtures with two different binders (HTPB, GAP) and three oxidizers (AP, ADN, KDN) were used. Lab-scale combustion experiments were performed in free atmosphere. All investigated samples satisfied the combustion properties as well as the spectral requirements. The comparison of the two binders containing the same oxidizer shows that GAP always provides better spectral results than HTPB, while the tested dinitramide oxidizers do not have great advantages compared to AP. The most promising mixture of this study is probably the sample Al/CuO - GAP - AP. It is convincing by its good burning behaviour, spectral characteristics and the best v/a ratio.