Investigation of the ignition and combustion of compressed aluminum/polytetrafluoroethylene bulk composites

The thermal pyrolysis process of mold-compressed Al/PTFE composites has been investigated. TG–DSC analysis of the Al/PTFE composites revealed a slight exothermic pre-reaction in the range 500–600 °C. Based on XRD and XPS analyses of Al/PTFE composites subjected to heat treatment at 500–600 °C, this pre-reaction is believed to be fluoridation of the alumina passivating layer on the surface of Al particles. This fluoridation has been confirmed to be a crucial factor in triggering the ignition of aluminum particles in an O₂ flow at a temperature much lower than the melting point of aluminum (660 °C). The energetic properties of the Al/PTFE composites have been studied, and the compositions of their combustion residues have been analyzed by XRD. The results indicated that the energy release from the composites and the compositions of their solid combustion residues were determined by their PTFE contents. Composition analysis of these combustion residues has revealed the formation of AlF₃, Al₂O₃, Al₄C₃, and amorphous carbon.