AbstractA survey of earlier work in the field of reactions of solids introduces the thesis. The conclusions derived from these researches are discussed.
Reactions of trilead tetraoxide (red lead) and lead dioxide as oxidants with powdered silicon were extensively studied. The experimental methods and apparatus used are described. The study can be divided into two parts:
(1) Study of the burning characteristics of the pelletted oxidant/fuel compositions.
(2) Study of small samples of powdered mixtures of the same compositions at controlled conditions by thermal analysis techniques.
In the first, the delay time and the rate of burning of the compositions are measured and the influence of diluents, ambient temperature and pressure, particle size and other variables are determined and mathematical relationships arrived at. Heats of reaction data are utilized to select the most probable reaction taking place, and a correlation between the heat evolved and the rate of burning is established.
A detailed study of the mechanism of the self-sustained reaction between red lead and silicon was performed by the method of temperature profile analysis and a mathematical model for the propagation is put forward. The temperatures of the burning compositions are measured and compared with theoretically calculated maximum temperatures, and a theory is put forward as to the temperature of reaction below which combustion reaction is no longer possible.
In the thermal analysis study, the stages of the reactions and the temperatures at which these reactions proceed are established. Also studies of the individual components such as oxidants, silicon and binder are carried out and the effect of varying conditions such as rate of heating, atmosphere under which reaction occurs, and the presence of binder, are investigated.
From DSC and TG, a mathematical model for the decomposition reaction of the oxide and the exothermic reactions of oxidant/fuel is put forward.
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