The effect of some additives on the closed bomb burning and ignitability of RDX/TNT (60/40)

Abstract The burning and ignition properties of Composition (Comp) B are studied so that formulation modification could be made that would reduce gun projectile in-bore thermal explosions. Comp B first burns on its surface like a gun propellant; then, at a pressure near 100 MPa, a sudden breakup burning phase develops. New surface area is created at a phenomenal rate, and this is the cause of the catastrophic reaction rates that it can experience. Coating its RDX constituent with a protectant significantly slows this reaction rate. It appears to do this by inhibiting the rate at which the RDX is released from the TNT matrix for burning, probably by infinitesimally delaying the ignition of the RDX in the particle ignition sequence. A new test that evaluates explosive ignitability as a function of pressure and energy indicates that an RDX protective coating may also increase the level of thermal ignition and delay the onset of a thermal explosion. Collectively, these three desirable properties, caused by a single modification, may significantly reduce the incidence of in-bore explosions where casting flaws would have precipitated this event.