Investigation of shock-wave initiation in metal- teflon powder mixtures

Abstract

The article is aimed at studying features and conditions of initiation, reaction, and final phase formation in the energetic condensed metal-teflon systems under shock wave loading. Thermodynamic calculations were carried out using the TERMO program. 16 different mixtures were made on the basis of the calculations. The adiabatic combustion temperatures, the composition and quantity of condensed products and the volume of gaseous products were calculated. To increase the combustion temperature, teflon powder was used as one of the components. The calculations showed that the compositions provided a sufficiently wide range of adiabatic combustion temperatures from 1190°C for Cu–Al–C2F4 composition to 3280°C for Hf-B-C2F4. The compositions based on Ni–Al, Cu–Al and Nb–Al with teflon differed in predominance of liquid phase in the products at relatively low combustion temperatures (1740ºС, 1190ºС and 1410ºС, respectively). Shock-wave loading of the samples was carried out in a multi-cell matrix by throwing a flyer. The acceleration of the flyer was carried out by detonation of the explosive. The detonation was initiated by an electric detonator located in the center along the assembly axis. Thus, the design of the recovery fixture provided the same loading conditions in all the cells. Ni–Al, Ni–Al–C2F4, Ti–B–C2F4, Hf–B–C2F4 systems reacted most completely. Thus, the systems based on metals (titanium and hafnium) with additives of boron and teflon are the most promising ones to be used as a reaction material from the viewpoint of the achieved synthesis temperature, initiation by shock-wave action and the reaction completeness.