Development and Performance of the W/Sb 2 O 3 /KIO 4 /Lubricant Pyrotechnic Delay in the US Army Hand‐Held Signal

Gassy pyrotechnic delays composed of tungsten, antimony(III) oxide, potassium periodate, and various lubricants have been developed for use in the US Army hand‐held signal. The new compositions were developed to replace the current formulation, which contains potassium perchlorate and barium chromate, chemicals that are facing increasing scrutiny due to environmental regulation. The hand‐held signal delay housing was used to demonstrate the burning rate tunability of the new compositions. The addition of 1–5 % of waxy lubricants (stearic acid or calcium stearate) was found to have a profound effect on burning rate. The effect of tungsten content and the Sb 2 O 3 /KIO 4 ratio on burning rate was also probed. A wide range of inverse burning rates (2 to 15 s cm −1 ) were demonstrated, which encompasses the 7 to 8.5 s cm −1 range required by the hand‐held signal. The W/KIO 4 reaction produces I 2 , which was observed by visible spectroscopy in the vapor above a sample of combustion residue.