Focke, Walter WilhelmTichapondwa, Shepherd MasimbaMontgomery, Yolandi C.Grobler, Johannes MarthinusKalombo, Michel L.2019-11-152019-01Focke, W.W., Tichapondwa, S.M., Montgomery, Y.C. et al. 2019, 'Review of gasless pyrotechnic time delays', Propellants, Explosives, Pyrotechnics, vol. 44, no. 1, pp. 55-93.1521-4087 (online)0721-3115 (print)10.1002/prep.201700311http://hdl.handle.net/2263/72306Gasless pyrotechnic delay compositions for time‐sequencing energetic events are reviewed. They are mixtures of powdered fuels and oxidants capable of a highly exothermic oxidation‐reduction reaction. Trends favor ‘green’ compositions targeted to replace compositions containing perchlorates, chromates, lead and barium. Thermite‐based reactions dominate but intermetallics (especially multi‐layered versions) and hybrids appear promising considering progress in self‐propagating high temperature synthesis technology. Improving computer modelling will require better description of condensed phase reactions. Progress was made with the development of “hot spot” models and expressing reactivity in terms of the number of contact points (or contact surface area) between particles. Promising processing advances include mechanochemical synthesis of reactive particle composites by arrested milling or comminution of cold‐rolled multilayer intermetallics. Dry mixing of reactive powders has made way for slurry mixing followed by spray drying.en© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim. This is the pre-peer reviewed version of the following article: 'Review of gasless pyrotechnic time delays', Propellants, Explosives, Pyrotechnics, vol. 44, no. 1, pp. 55-93, 2019. doi : 10.1002/prep.201700311. The definite version is available at : http://www.pep.wiley-vch.de.Burning ratePyrotechnicThermiteTime delaySelf propagating high temperature synthesisMechanochemical synthesisExothermic oxidationContact surface areaCondensed phase reactionsRedox reactionsMixingMetal claddingIntermetallicsComminutionCold rollingChromatesPostprint Article