CL-20 based energetic thin films: Micro-spray molding and micro-detonation

Abstract

In order to solve the problem of low sample forming efficiency and uncontrollable crystal type in inkjet printing, a formula of explosive ink suitable for micro-spraying is designed by using hexanitrohexaazaisowurtzitane (CL-20) as the main explosive, the compound of polyazide glycidyl ether and ethyl cellulose as the bonding system, ethyl acetate as the solvent, and the refined ε-CL-20 as the seed crystal in this paper. The optimal process conditions were determined, and under the optimal process conditions, the explosive ink is written on an aluminum substrate or a glass substrate by micro-spraying direct writing technology, and CL-20 based energetic thin film forming samples are characterized. The results show that the CL-20 crystal form in the sample is ε type and the molding effect is good. The optimum process conditions are as follows: the nozzle has an air pressure of 0.02 MPa, the height is 40 mm, the spraying rate is 0.4 ml min−1, and the substrate temperature is 50°C. The explosive particles in the energetic thin films are spherical. The particle size is about 10 µm, and the particle size distribution is relatively uniform. The density of the composite is 1.567 g cm−3, and the molding density can reach 80.2% of the theoretical density. The activation energy is 242.07 kJ mol−1. The characteristic drop height H50 is 38.5 cm. When the charge width is 0.8 mm, the critical size of the detonation is 0.8 × 0.03 mm2. The detonation wave formed after the shaped sample is detonated in a small groove with a cross-sectional dimension of 1.0 × 1.0 mm2 can successfully pass through multiple continuous 90° charging corners.