Influence of the Density of PETN–Coal Composites on the Threshold Characteristics of Explosive Decomposition in Laser Initiation

Abstract

This paper presents the results of measuring the thresholds of explosive decomposition of PETN–coal under the action of laser radiation pulses ( $$\lambda$$ = 1064 nm and $$\tau$$ = 14 ns). Samples whose thickness is 1 mm and whose densities are 1.1 and 1.7 g/cm3 with inclusions of submicron particles of brown coal (750 nm) are investigated. Matrices in composites with densities of 1.1 and 1.7 g/cm3 are almost transparent for radiation. A minimum explosive threshold of 1.8 J/cm2 is reached with a concentration of inclusions of 0.5% (by weight). The explosion is adiabatic. Composites with a density of 1.1 g/cm3 have a scattering matrix. A minimum explosive threshold of 2.3 J/cm2is obtained for a concentration of inclusions of 1%. An extinction rate is estimated: $$k_{\rm ext}$$ = 135 cm- 1. Radiation is absorbed at a depth of $$<$$ 0.1 mm. Explosive decomposition in an unirradiated section develops according to the shock-wave mechanism of explosive combustion.