Submicron Potassium Perchlorate: A Key Component To Reach Detonation In Binary Mixtures With Titanium Hydride

The pyrotechnic compositions made up of potassium perchlorate (KClO4) and titanium hydride (TiH2), known as THKP, have a fast deflagration velocity (similar to 500 m/s), along with low sensitivity and high stability. In this research, a new kind of THKP was formulated from a submicron powder of KClO4 (50-400 nm) prepared by the Spray Flash-Evaporation (SFE) process. The use of fine KClO4 not only ensures better oxidation of TiH2, but also leads to a transition to detonation in the THKP. This transition is observed in loose powders placed in small diameter tubes (3 mm). The distance of transition is relatively short (17-22 mm) and increases with the KClO4 content of the THKP mixture. The detonation front propagates steadily, at a velocity of similar to 1250 m/s in THKP powders with 86 % of porosity. The shockwave velocity varies little with the perchlorate content in the domain of composition studied (55-74 wt.% of KClO4). Conversely, in the classical THKP mixtures prepared from micron-sized KClO4 and tested in the same conditions, no transition to detonation is observed; the combustion slows down and eventually stops. Finally, owing to their high sensitivity thresholds to impact (S-Imp.>= 44.7 J), friction (S-Fr.>= 192 N), and electrostatic discharge (S-ESD >= 34.7 mJ), THKP mixtures prepared from submicron KClO4 can be classified as low-sensitivity primary explosives.