Development of a Sustainable Perchlorate-Free Yellow Pyrotechnic Signal Flare

Abstract

Novel yellow-light emitting pyrotechnic compositions absent perchlorate oxidizers were investigated for use in the Mk 144 marine smoke and illumination signal. In laboratory-scale testing, three candidate formulations met or surpassed performance metrics of luminous intensity, dominant wavelength, color purity, and burn time when compared to a mock Mk 144 formulation which currently utilizes the environmentally hazardous potassium perchlorate. Also, one identified formulation does not utilize any barium compounds which may be the focus of future regulations. Furthermore, these candidate systems exhibited similar insensitivity to electrostatic, friction, and impact ignition stimuli in comparison to the mock Mk 144 formulation. Therefore, replacement formulations for the Mk 144 marine smoke and illumination signal have been identified with increased performance, environmental sustainability, and acceptable safety characteristics.

The Flame Emission of Indium from a Pyrotechnical View

“…This observation can be explained by a higher potassium concentration present in the flame, which is also known for other alkaline metals like lithium . The broad emission at 496 nm was assigned to condensed MgO (s) particles . Next to the identified emission lines of indium, sodium and potassium, several new unidentified lines at 404, 510, 517, 534, 581, 669, and 693 nm appeared.…”

“…[31] The broad emission at 496 nm was assigned to condensed MgO (s) particles. [32] Next to the identified emission lines of indium, sodium and potassium, several new unidentified lines at 404, 510, 517, 534, 581, 669, and 693 nm appeared. Again, the intensity of the emitted light in the blue region was too low to produce a blue color impression.…”

Pyrolysis/GC/MS as a Method to Rapidly Profile Pyrotechnic Formulations for Objectionable Gaseous Emissions

“…27 We chose to interrogate the volatile gaseous reaction products of a novel yellow signal flare (YSF) pyrotechnic as a model system. 28 The YSF formulation was engineered as a "green" perchlorate-free replacement formulation (shown in Table 1) that notably meets the performance objectives of the United States Navy's Mk 144 marine smoke and illumination signal, yet contains a barium salt oxidizer along with the polymer ingredients of PVC and epoxy binder resins that may generate toxic emissions upon combustion. 29,30 Pyrolysis/GC/ MS, offers a means to quickly screen emission products for volatile organic compounds (VOCs) that are deemed hazardous, including those that may not be produced by any of the individual components alone.…”

Development of a Sustainable Perchlorate-Free Yellow Pyrotechnical Strobe Formulation

“…In the United States, amusement parks such as Disney World and the U.S. Army training grounds show a high consumption of pyrotechnical formulations . In 1997, the critical concentration of the perchlorate anion in groundwater exceeded the maximum permissible level advised by the U.S. Environmental Protection Agency (EPA), which resulted in an all live fire training stop at Camp Edwards. , The main health threat of perchlorate oxidizers arises from the similar ionic radius compared to that of iodine, which results in an interference with iodine uptake in the thyroid gland . For decades, perchlorates have been used as the oxidizer of choice, but with increasing environmental regulations, the need for alternatives has increased .…”

“…For decades, perchlorates have been used as the oxidizer of choice, but with increasing environmental regulations, the need for alternatives has increased . In contrast to the field of constant burning (i.e., flare) formulations, where perchlorate was already successfully replaced for the colors blue, green, red, and yellow to name only a few, there is a lack of perchlorate/chlorine- and heavy-metal-free options for strobe formulations. ,− Recently, we reported the development of a red strobe system based on lithium nitrate fulfilling the preset requirements . Strobe formulations are characterized by a periodically alternating flash (big flame, bright light) and dark phase (small or no visible flame) reaction .…”