Pyrophoric articles

Articles, Pyrophoric Articles which contain a pyrophoric substance (capable of spontaneous ignition when exposed to air) and an explosive substance or component. The term excludes articles containing white phosphorus. UN App. B, ICAO A2, US 173.59, lATA App. A... 

Although phosphine [7803-51-2] was discovered over 200 years ago ia 1783 by the French chemist Gingembre, derivatives of this toxic and pyrophoric gas were not manufactured on an industrial scale until the mid- to late 1970s. Commercial production was only possible after the development of practical, economic processes for phosphine manufacture which were patented in 1961 (1) and 1962 (2). This article describes both of these processes briefly but more focus is given to the preparation of a number of novel phosphine derivatives used in a wide variety of important commercial appHcations, for example, as flame retardants (qv), flotation collectors, biocides, solvent extraction reagents, phase-transfer catalysts, and uv photoinitiators. 

L) Explosive substance or article containing an explosive substance and presenting a special risk (e. g., due to water activation or the presence of hypergolic liquids, phosphides, or a pyrophoric substance) necessitating isolation of each type. 

Pyrophoric articles include any device containing a chemical that spontaneously combusts, such as some pyrotechnics, smoke devices, explosives, etc. 

Decoy materials of this composition undergo the above reaction to reach temperatures of 820°C in less than one second and above 750°C for twelve secrmds after their exposure to air. Presently this type of material is used in a commercial decoy flare that is composed of pyrophoric iron coated onto steel foil articles [35]. Due to increasingly demanding materials performance, environmental standards, aging, and duty-cycle, there exists a need for continued development of new materials and approaches to achieve pyrophoric materials with tailorable output. 

There have been several reports of applying sol-gel materials and techniques to the formulatiOTi of nanostructured pyrophoric materials. The application of sol-gel materials to this technology area has involved three different approaches, which include (1) use of the aerogel as a framework for the deposition of pyrophoric materials (2) direct transformation of the aerogel skeleton itself (metal oxide) to a pyrophoric or easily combustible article and (3) use of an aerogel network as a reactive template for the reduction of a second sol-gel metal oxide phase to a pyrophoric or readily combustible material. 

While not pyrophoric, the porous copper metal monolith is readily combustible by the application of a flame in air. In addition to copper, this method has been appUed to prepare other nanoporous metals such as iron, cobalt, nickel, and tin, as well as carbides of chromium, titanium, and hafnium (Chap. 14). This method is especially powerful as it appears to be applicable to a wide variety of metals and affords articles that are mrmolithic. 

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