Thermal-cum kinetic behavior of Thermites

Raja Muhammad Asif Khan, Abdul Qadeer Malik

Abstract


Aluminum and metal oxide react with each other in a thermite reaction to produce a large amount of heat. In this paper various thermite compositions were synthesized and the ignition temperatures of these thermites were measured using Differential Thermal Analysis/Thermo Gravimetric Analysis. First is the discussion of the behavior, applications, benefits and characteristics of thermite mixture as a subclass of energetic materials. Secondly, five different thermite compositions Aluminothermite, Copper thermite, Chromium thermite, Zinc thermite and lead thermite were synthesized by mixing fuel and the oxidizer in stoichiometric ratios. Aluminothermite was synthesized by two different ways i.e. by simple physical mixing and by using n-Hexane as solvent. Finally, the ignition temperatures of these thermite systems were investigated by using Differential Thermal Analysis/Thermo Gravimetric Analysis at different scan rates in Nitrogen atmosphere. It was found that ignition temperatures of these systems range between 800 to 1250°C. Thermite reactions are difficult to start as they require very high temperatures for ignition, e.g. for Al–Fe2O3 thermite is ca. 1220 °C. Also, the influence of heating rates on the Differential Thermal Analysis behavior of the mixtures was verified. The results showed that as the heating rate was decreased, ignition temperatures of the mixtures were also decreased. Ignition temperature of Aluminothermite was reduced from 1220 to 1130°C when the heating rate was lowered from 10 - 5 °C /min. It was also observed that the ignition temperature is significantly reduced when the binary Si–Bi2O3 system is added as sensitizer in Copper thermite system. The ignition temperature of the system was 1020 °C which was reduced to 890 °C after using sensitizer.


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DOI: http://dx.doi.org/10.24949%2Fnjes.v5i1.46

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ISSN (Print): 2070-9900   ISSN (Online): 2411-6319