Features of Initiation and Combustion of Hf/PTFE Reactive Materials

The optimum composition of components in the Hf/PTFE system was determined by thermodynamic calculation. The composition 65Hf/35PTFE (in wt %) was chosen based on the maximum adiabatic combustion temperature (T-ad = 2381 degrees C) and the fraction of condensed products (70 wt %). The study on the ignition of compositions in argon, air, and vacuum showed that in the latter case, the intensity of ignition decreases. The maximum combustion temperature and rate in argon were found to be 2250 degrees C and 4.5 mm/s for compositions with 10 and 15 wt % Al. XRD analysis revealed the formation of a monophase HfC product in all compositions. Shock-wave loading of compositions with a steel plate at an impact velocity of 1 km/s showed the absence of exothermic reaction in the 65Hf/35PTFE composition. Increasing the impact velocity to 1.5 km/s resulted in an exothermic reaction in this composition. The maximum yield of HfC under shockwave loading was achieved in the composition 62Hf/33PTFE/5Al, indicating its high reactivity. Thus, this composition is the most optimal for use as a reactive material.