ABSTRACT
A pyrotechnic composition must be capable of undergoing reliable ignition when an ignition stimulus is provided, and yet be stable in transportation and storage. The ignition behavior of every mixture must be studied, and the proper ignition system can then be specified for use with each composition. For easily ignited materials, the “spit” from a burning black powder fuse is often sufficient. The ignition method for propellants is frequently an impact-sensitive energetic “primer” that produces a spray of hot particulates and flame to rapidly get the propellant burning. Another common igniter is an electric match, consisting of a wire circuit terminating in a smalldiameter bridgewire that is coated with a small dab of heat-sensitive composition. An electric current is passed through the circuit, producing sufficient heat to ignite the bridgewire composition and produce a flame. The burst of flame then ignites the next composition in the ignition sequence. For pyrotechnic mixtures with high ignition temperatures, a priming composition or first fire is often used. This is an easily ignited composition that can be reliably activated by a fuse or other igniter. The flame and hot particulates that are produced are then used to ignite the main composition.
