Research On Micro-spraying Molding And Performance Of CL-20 Based Energetic Film

Micro Electronic Mechanical Systems(MEMS)is an emerging research field.MEMS pyrotechnic devices have the characteristics of miniaturization,intelligence,integration and multi-functionality,and they have good applications in miniature ammunition and small-caliber ammunition.In the future,how to realize the high-precision,high-quality and high-efficiency charge of MEMS pyrotechnics is a research hotspot in the field of pyrotechnics.This paper attempts to combine micro-spraying and direct writing technology,and formulation of energetic spraying material and direct writing method of micro-spraying for MEMS pyrotechnics are developed.On this basis,the hexanitrohexaazaisowurtzitane(CL-20)based energetic film is prepared,and the molding effect,microstructure,safety performance and detonation performance of the sample are tested and analyzed.The specific content is as follows:(1)Firstly,the composition of micro-single spray material is determined.CL-20 is used as the main explosive,ethyl cellulose(EC)and polyglycidyl azide(GAP)are used as the binding system,fluorosurfactant(FS-3100)and dipropynol succinate(BPS)are used as an auxiliary agent,and a certain proportion of refined?-CL-20 is added as a seed crystal,and ethyl acetate is used as a solvent to design and prepare a suspension spray material.The distribution ratio of each group is:85.65%wt raw material CL-20,7.73%wt GAP and EC,1.1%wt FS-3100 and BPS,and 5.52%wt refined CL-20.Then,the composition of the micro double spray spraying material is determined,CL-20 is used as the main explosive and ethyl acetate is used as the solvent to design and prepare the explosive ink spray material,the distribution ratio of each group is:17.2%wt CL-20 and 82.8%wt ethyl acetate;EC and GAP are used as the composite bonding system and acetone is used as the solvent to design and prepare the adhesive spray material,the distribution ratio of each group is:0.55%wt EC,1.38%wt GAP and 98.07%acetone.(2)The single-factor variable method is used to optimize the micro-single spray direct writing molding process,and the obtained optimization conditions are:inlet pressure 0.01MPa,flow rate 0.4 m L/min,substrate temperature 50?,and nozzle height 40 mm.Under the experimental conditions,the micro-spraying platform is used to deposit the sprayed material on the glass substrate or aluminum plate in a single spray mode to obtain a CL-20 based energetic film molding sample.Finally,scanning electron microscope(SEM),electron densitometer,X-ray diffractometer(XRD),differential scanning calorimeter(DSC),nanoindenter and ERL-12 drop weight instrument are used to analyze the energetic film.The microstructure,molding density,crystal form,thermal decomposition performance,mechanical properties and impact sensitivity are tested and characterized,and the detonation performance is also tested and analyzed.The results show that the surface of the CL-20 based energetic film is flat,the crystal form of CL-20 in the film has not changed.Compared with the raw material,the thermal stability of the molded sample is better,the impact sensitivity characteristic is increased by 21 cm,and its elastic modulus and hardness values reach 17.12GPa and 0.361 GPa,respectively.The detonation critical dimension of CL-20 based energetic film is 0.8 mm×0.03 mm,and the explosion velocity is 6172 m/s when the charge density is1.567 g/cm~3.When the cross-sectional size of the charge is 1.0×1.0 mm,the critical detonation corner is 150°,and the detonation wave can pass through multiple consecutive 90°corners,showing good micro-scale detonation capability.In addition,micro-charges can also achieve detonation transmission in the"one-in,four-out"explosion network,and it also has a good application prospect in the micro-scale explosion network.(3)The orthogonal test method is used to obtain the optimal conditions for dual-nozzle collaborative spraying:nozzle height 40 mm,platform movement speed 20 mm/s,glue flow rate 0.4 m L/min,explosive flow rate 0.6 m L/min,substrate temperature 50?and inlet pressure 0.05 MPa.Using the micro-spraying platform,the dual-nozzle coordinated spraying mode is used to alternately deposit the explosive ink spraying material and the adhesive spraying material on the glass substrate and the aluminum plate to obtain the CL-20 based energetic film.The microstructure,crystal form,density,thermal stability and impact sensitivity of the film are tested and characterized by SEM,XRD,electron densitometer,DSC and ERL-12 drop weight meter,and the critical size of its detonation is tested and analyzed.The results show that the surface of the CL-20 based energetic film molding sample is flat and the two spray materials are deposited alternately.The crystal form of CL-20 in the sample does not change.Compared with the raw material CL-20,the apparent activation energy of the obtained sprayed sample is increased by about 10 k J/mol,and the impact sensitivity characteristic(65.7 cm)is increased by more than 3 times,showing good safety performance.In addition,the CL-20 based energetic film has good micro-scale detonation ability,and its critical detonation dimension is 1.0 mm×0.045 mm.The explosion velocity is 6017 m/s when the charge density is 1.547 g/cm~3.