Characterization of a Fe2O3/Al/polyoxymethylene thermite composition

This work investigated a new thermite formulation consisting of Fe2O3, Al and polyoxymethylene (POM), with potential applications as a propellant in fireworks. Unmodified Fe2O3/Al mixtures were found to have ignition energies between approximately 30 and 40 kJ mol(-1) while Fe2O3/Al/POM compositions exhibited ignition energies of about 20 kJ mol(-1). Fe2O3/Al formulations mixed in weight ratios of 4/6, 5/5, 6/4 and 7/3 all had similar minimum ignition temperatures in the range of 500 to 600 K. The addition of POM lowered the ignition temperature to between 400 and 500 K. The maximum pressure obtained from a Fe2O3/Al/POM (5/5/20 weight ratio) mixture during testing was 2100 kPa, exceeding the pressures obtained from CuO/Al/POM, CaO2/Al/POM and black powder formulations. The solid combustion products resulting from this new formulation were identified as Fe and Al2O3,which are thought to originate from the reaction Fe2O3 + 2Al -> Al2O3 +2Fe. The results of this study indicate that Fe2O3/Al/POM compositions show promise as energetic components of fireworks.