A Strontium‐ and Chlorine‐Free Pyrotechnic Illuminant of High Color Purity

The development of a red‐light‐emitting pyrotechnic illuminant has garnered interest from the pyrotechnics community owing to potential regulations by the United States Environmental Protection Agency (U.S. EPA) regarding the use of strontium and chlorinated organic materials. To address these environmental regulatory concerns, the development of lithium‐based red‐light‐emitting pyrotechnic compositions of high purity and color quality is described. These formulations do not contain strontium or chlorinated organic materials. Rather, the disclosed formulations are based on a non‐hygroscopic dilithium nitrogen‐rich salt that serves as both oxidizer and red colorant. These formulations are likely to draw interest from the civilian fireworks and military pyrotechnics communities for further development as they both have a vested interest in the development of environmentally conscious formulations.     

Safer Pyrotechnic Obscurants Based on Phosphorus(V) Nitride

The potential of phosphorus(V) nitride, P₃N₅ , as a replacement for red phosphorus, P_R, in pyrotechnic obscurants has been theoretically and experimentally investigated. P₃N₅ can be safely mixed with KNO₃ and even KClO₃ and KClO₄ . The corresponding formulations are surprisingly insensitive to friction and only mildly impact‐sensitive. P₃N₅ /KNO₃ pyrolants with ξ=20–80 wt % P₃N₅ burn 200 times faster than the corresponding mixtures based on P_R and generate a dense smoke. Hence obscurants based on P₃N₅ /KNO₃ have a figure of merit that by far exceeds that of current state‐of‐the‐art P_R‐based obscurants. Furthermore, unlike P_R, which slowly degrades in moist air to phosphoric acids and phosphine (PH₃), P₃N₅ is stable under these conditions and does not produce any acids or PH₃ . P₃N₅ is hence a safe, stable, and powerful replacement for P_R for use in insensitive munitions.     

Energy release in the reaction of metal powders with fluorine containing polymers

Fluorine and its derivatives have been used as a substitute to oxygen-containing oxidizers in higher performing propellants and other energetic materials. They typically react rapidly with metals or thin oxide layers of the metals to produce metal fluorides, generally in the gaseous state.Thermal reactions of stoichiometric mixtures of metal (M=Al, Ti) -F containing polymers have been studied using thermal analyzers and their energetics are compared with the metals in other halogen element containing oxidizers. The experimental results indicated that thermal reaction becomes more exothermic as the bond strength between Al-X (X=F, Br, I) becomes stronger. It was also found that oxidation of metal powders is largely affected by the size of metal powders as well as the nature of existing oxide layer.     

Some Thermal Studies on Pyrotechnic Compositions

Some applications of thermal analysis (TA) and temperature profile analysis (TPA) to the study of a variety of binary pyrotechnic systems are described. Factors that effect the combustion of such fuel/oxidant mixtures are discussed. Trends in burning behaviour and the experimental limitations of the techniques available are identified. This revised version was published online in July 2006 with corrections to the Cover Date.     

Projectile dynamics at low barrel pressures

A mathematical model for a projectile shot at low pressures in the space behind the projectile space is developed. The pressure rise is limited because of the nonsimultaneity of propellant ignition and combustion and the discharge of the propellant combustion products through the gap between the projectile and the walls of the gun barrel. The kinetic characteristics of flame propagation over the propellant particles are determined. A comparison of calculation and experimental data is performed. The calculation results are used in designing 2A85 self-propelled launchers and upgrading 2A30 self-propelled launchers. __________ Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 48, No. 6, pp. 44–49, November–December, 2007.     

Chlorine‐Free Pyrotechnics: Copper(I) Iodide as a “Green” Blue‐Light Emitter

The generation of blue‐light‐emitting pyrotechnic formulations without the use of chlorine‐containing compounds is reported. Suitable blue‐light emission has been achieved through the generation of molecular emitting copper(I) iodide. The most optimal copper(I) iodide based blue‐light‐emitting formulation was found to have performances exceeding those of chlorine‐containing compositions, and was found to be insensitive to various ignition stimuli.     

Study of Six Green Insensitive High Energetic Coordination Polymers Based on Alkali/Alkali‐Earth Metals and 4,5‐Bis(tetrazol‐5‐yl)‐2 H‐1,2,3‐triazole

Constructing insensitive high‐performance energetic coordination polymers (ECPs) with alkali/alkali‐earth metal ions and a nitrogen‐rich organic backbone has been proved to be a feasible strategy in this work. Six diverse dimensional novel ECPs (compounds 1 – 6 ) were successfully synthesized from Na^I, Cs^I, Ca^II, Sr^II, Ba^II ions and a nitrogen‐rich triheterocyclic 4,5‐bis(tetrazol‐5‐yl)‐2 H ‐1,2,3‐triazole (H₃BTT). All compounds show outstanding stability and low sensitivity, the thermal stability of these ECPs are significantly improved as the structural reinforcement increases from 1D to 3D, in which the decomposition temperature of 3D Ba^II based compound 6 is as high as 397 °C. Long‐term storage experiments show that compounds 5 and 6 are stable enough at high temperature. Moreover, the six compounds hold considerable detonation performances, in which Ca^II based compound 5 possesses the detonation velocity of 9.12 km s⁻¹, along with the detonation pressure of 34.51 GPa, exceeding those of most energetic coordination polymers. Burn tests further certify that the six compounds can be versatile pyrotechnics.     

High-nitrogen-based pyrotechnics: longer- and brighter-burning, perchlorate-free, red-light illuminants for military and civilian applications

The full-up prototype testing of perchlorate-free, hand-held, signal illuminants for the US Army's M126A1 red star parachute hand-held signal is described. Compared to the perchlorate-containing control, the disclosed illuminants yielded excellent stabilities toward various ignition stimuli while offering superior pyrotechnic performance. Militarily, the illuminants provided further evidence that development of smaller hand-held signal items in an environmentally conscious way is a realistic and obtainable goal. The results are also important from the perspective of civilian fireworks, as the development of brighter, longer-burning, and environmentally compatible red-light-emitting pyrotechnics is now possible.