Optical sensitising of insensitive energetic material for laser ignition

•Carbon black (CB) as an optical sensitiser was successfully used to ignite insensitive explosive by a diode laser.•The mixture samples were characterised by microscopy to examine the dispersion of carbon black.•The effects of mixing methods for adding CB in 1,1-Diamino-2,2-dinitroethene (FOX-7) on laser ignition were addressed.•Ground mixing method achieved a lower laser ignition threshold than that of tumble mixing method. An experimental investigation into optical sensitisation for laser ignition of an insensitive explosive 1,1-Diamino-2,2-dinitroethene (FOX-7) has been carried out, by using a near-infrared diode laser at a wavelength of 808 nm. In this study carbon black as the optical sensitiser was mixed at 5 wt% with the explosive using two different mixing techniques, tumble mix and ground mix. The mixture samples were characterised by microscopy to examine the dispersion of carbon black within the mixtures and analyse effects of the mixing techniques on their laser ignitability. Laser ignition maps were developed for both mixing techniques and varying sample densities also examined to determine the density effect on laser ignition with various laser parameters of beam width, laser duration and laser power. The results have shown that ground mixing method provides more uniform dispersion of carbon black in the mixture samples, and therefore allows a lower laser ignition threshold than that of tumble mixing method.