Future pyrotechnics

Pyrotechnics will take an important step forward by making use of several nanosized fuels and oxidizers for pyrotechnic formulations in the near future. As a result, the performance of such pyrotechnic formulations will become considerably better and thus the problem of availability of space for pyrotechnic devices will not remain as critical as it is now, because several metal powders and oxidizers are commercially available at the nanoscale these days. Before we discuss nanosized fuels, oxidizers and their formulations, it is considered essential to describe in brief nanomaterials (NMs)including carbon nanotubes (CNTs), their methods of preparation, their properties in general, and some important applications. 

Some recent and future trends in terms of new materials for pyrotechnic applications are as follows ... 

R.K. Wharton, Areas for Future Safety Research Identified by Recent Accidents in the Pyrotechnic Industry , Proceedings of the /(S International Pyrotechnics Society, JbnkOping, Sweden, 1991. 

The sulfide melts have unique chemical properties. Chemical reactions which occur in water do not always occur in sulfide melts. The author was surprised to find evidence of strong oxidizing ions, such as peroxides, dissolved in sulfide melts. In water, sulfide ion will reduce iodine to iodide and potassium peroxide, and superoxide will oxidize aqueous iodide solutions to iodine, or further to periodate ion. It is not surprising that much of the literature about pyrotechnically produced sulfide melt sparks is filled with reports of chemical species which do not exist at 800°C, such as the thiosulfate ion. These ions are quickly formed when the melts are dissolved in water prior to analysis. The author found radically different chemistry occurring at room temperature for spark droplets only seconds after collection by freezing. Some of the sulfide melts studied were not stable for more than one half second after capture. Special handling techniques were, and are, being developed. As techniques evolve the future may yield better data. Chemistry is an effort to be better informed tomorrow than is possible today. 

It must be born in mind that much of what is presented here is application of modern theoretical inorganic chemistry and is a deliberate simplification of what is a complex problem. The future holds better data and from that data, better pyrotechnic effects. 

An electronic delay element for certain propellant-actuated device is described in a Frankford Arsenal report,About 3 in, in volunv and 4 oz in weight, it is claimed to permit delaytimes of 0.I-I5 set with a 3% accuracy over an interval of —65 to +200 F. By comparison with pyrotechnic standards superior performance, this is surpassed by another device, for which incremental delay times of 0.1 sec up to 1000 sec are claimed with an accuracy of 0,1 %. The future will show if the above-described advantages of pyrotechnic delays (economy, ruggedness, producibility) will outweigh the performance characteristics of electronic or mechanical delays. 

Heavy metal nitrates are all highly hydrated but the anhydrous salts can be synthesized by special methods or, exceptionally, obtained by careful dehydration. Perhaps they belong to the pyrotechnics of the future. Thorium and cerium nitrate are actually found in a patented flare formula and in some old flash powders for civilian use, purportedly because of lower smoke formation of the residual oxide and perhaps with the thought of selective spectral emission from the rare earths. 

It is also possible that more use will be made in the future of electronic delays containing no pyrotechnic delay component, particularly in more sophisticated devices. These electronic delays should provide higher precision and avoid the manufacturing variability that is inherent with the production of pyrotechnic devices. Delays of this type have already been introduced in commercial blasting detonators to achieve improved blasting results via precise delay intervals (for more information, do a web search for the term electronic delay detonators). 

His developing academic career was interrupted by the advent of World War n. Ted spent the war in various military research establishments, particularly in South Wales, working on pyrotechnic compounds for flares and tracer bullets, which, with characteristic deprecating humour, he referred to as fireworks . It was there that he met his future wife, Mary, with whom he had a long and very happy marriage. He also found the time to research material for a book on Chemical Thermodynamics, published by Oxford University Press in 1958. 

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