Flame spread over aluminum nanopowder embedded into a polymeric matrix burning in an oxygen-nitrogen counterflow

This study concerns flame spread over aluminum nanopowder embedded in a polymeric matrix burning in an oxidizing gas counterflow. We used two qualities of aluminum nanopowder produced by electrical explosion of aluminum wires: passivation with air and stearic acid. A mixture of 21 vol. % of oxygen and 79 vol. % of nitrogen was used as an oxidizer. The flame spread rate was measured as a function of oxidizing gas velocity. The temperature evolution was controlled depending on the zone in the burning sample, close or not to the exit of the oxidizer diffuser. The phase analysis showed that an effect of aluminum carbidation is characterized for this process. As for the case of combustion of a pure nanopowder in air, the phenomenon of nitrogen chemical fixation was found for the nanopowder embedded in polymer and burning with a counter-flowing oxidizer.