Activation energy of tantalum–tungsten oxide thermite reactions

The activation energy of a sol–gel (SG) derived tantalum–tungsten oxide thermite composite was determined using the Kissinger isoconversion method. The SG derived powder was consolidated using the high-pressure spark plasma sintering (HPSPS) technique at 300 and 400 °C. The ignition temperatures were investigated under high heating rates (500–2000 °C min−1). Such heating rates were required in order to ignite the thermite composite. Samples consolidated at 300 °C exhibit an abrupt change in temperature response prior to the main ignition temperature. This change in temperature response is attributed to the crystallization of the amorphous WO3 in the SG derived Ta–WO3 thermite composite and not to a pre-ignition reaction between the constituents. Ignition temperatures for the Ta–WO3 thermite ranged from approximately 465 to 670 °C. The activation energies of the SG derived Ta–WO3 thermite composite consolidated at 300 and 400 °C were determined to be 38 ± 2 kJ mol−1 and 57 ± 2 kJ mol−1, respectively.