PROGRESS TOWARDS MICROWAVE IGNITION OF EXPLOSIVES

It is known that various materials are caused to spark when subjected to microwave radiation, and others can be heated to extremely high temperatures. This paper studies the behaviour of graphite under microwave radiation using a multi-mode 2.45 GHz±50 Hz microwave cavity, and its potential applications in propellant ignition systems. Evidence for a correlation between sample mass and arcing intensity is presented, and a linear relationship between sample mass and temperature is found. Both graphite powder and flakes show increasing arcing intensity with increasing mass up to ∼150 mg, after which the behaviour is more dispersed. The temperature achieved increases linearly with increasing mass, with maximum temperatures of 1,011 deg. C and 657 deg. C achieved for powder (<0.1 mm) and flakes respectively--well above thermal ignition temperatures for most common explosives.