Energetics and Mechanism of Boron/Oxidant Combustion Reactions

  • Allen Goodfield

    Student thesis: Doctoral Thesis


    A brief introduction to the field of pyrotechnic time delays is given, followed by a survey of the published work in the field up to the present time.

    A description is provided of the experimental techniques, equipment and materials used.

    The energetics and mechanism of reaction in the boron/lead monoxide and boron/stannic oxide systems have been investigated by comparison with the more familiar, analogous silicon fuelled systems; the emphasis being placed on the boron/lead monoxide system.

    The heats of reaction of the four fuel/oxidant systems have been measured by the use of bomb calorimetry, the results being discussed in relation to the probable reactions taking place in each system. Conclusions have been drawn as to the nature of the reactions which provide heat outputs in excess of the theoretical values in the boron fuelled systems.

    The propagation rates of the four fuel/oxidant systems have been measured and the relationship between heat output and propagation rate in each system is discussed. An explanation is proposed for the apparently anomalous behaviour of the boron fuelled systems. The response of the propagation rates in each system to varying consolidation pressure has been investigated. An explanation is proposed for the difference in behaviour displayed by the boron and silicon fuelled systems.

    A method of non-contact temperature measurement using a recording infra-red brightness pyrometer has been investigated. The reaction temperatures of the four fuel/oxidant systems have been measured and their relationships to the response of the propagation rates of each system to consolidation pressure variations are discussed.

    The boron/lead monoxide reaction in loose powder mixes has been investigated using differential scanning calorimetry. Hot stage microscopy has been used to investigate boron/lead monoxide reactions in loose powder mixes and between consolidated pellets of the individual reactants. The thermal analysis results obtained demonstrate the effect of the boron oxidation product, B 2 0 3 , on the reaction rate and the role which it plays in the reaction mechanism in the boron/lead monoxide system. A reaction mechanism is proposed for the non-propagative reaction between boron and lead monoxide.

    The extraction and kinetic analysis of data from the differential scanning calorimetry investigation of the boron/lead monoxide system is discussed. It is demonstrated that the analysis of the dynamic data is virtually impossible due to the complexity of the peak patterns obtained.

    Date of AwardMay 1982
    Original languageEnglish
    Awarding Institution
    • Polytechnic of Wales

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