Activation energy of tantalum-tungsten oxide thermite reactions

摘要

The activation energy of a sol-gel (SG) derived tantalum-tungsten oxide thermite composite was deter-mined using the Kissinger isoconversion method. The SG derived powder was consolidated using the high-pressure spark plasma sintering (HPSPS) technique at 300 and 400℃. The ignition temperatures were investigated under high heating rates (500-2000℃ min~(-1)). Such heating rates were required in order to ignite the thermite composite. Samples consolidated at 300℃ exhibit an abrupt change in tem-perature response prior to the main ignition temperature. This change in temperature response is attrib-uted to the crystallization of the amorphous WO_3 in the SG derived Ta-WO_3 thermite composite and not to a pre-ignition reaction between the constituents. Ignition temperatures for the Ta-WO_3 thermite ran-ged from approximately 465 to 670℃. The activation energies of the SG derived Ta-WO_3 thermite com-posite consolidated at 300 and 400℃ were determined to be 38±2 kJ morl~(-1) and 57±2kJ morl~(-1), respectively.