Thermal analysis of black powder

Thermal analytical techniques such as thermogravimetry (TG), differential thermal analysis (DTA) and differential scanning calorimetry (DSC) have all been successfully employed in studying the pyrotechnic reactions of energetic materials such as black powder, as well as of binary mixtures of the constituents. 

TG is a method associated with mass change in which the mass of a substance is measured as a function of temperature whilst the substance is subjected to a controlled temperature programme. On the other hand, DTA is a method associated with temperature change in which the temperature difference between a substance and a reference material is measured as a function of temperature whilst the substances are subjected to a controlled temperature programme. 

Multiple techniques are also possible such as TG-DTA whereby the mass loss of a sample and the DTA curve may be obtained simultaneously. 

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The thermal analysis of black powders used for different purposes and containing differing proportions of ingredients can give an indication of the system stoichiometry by virtue of the rate and magnitude of measured exothermic events. 

Further hydrolysis proceeds much slower with very small heat evolution (for R = Et and Bun its value is zero within the accuracy of the experiment, while for R = Pr1 it does not exceed 20% of the overall reaction heat). Composition of the hydrolysis products for all h values approximately corresponds to Ti01s(0R) yR0H, where y = 0.15-1 depending on the nature of alcohol and concentration of alkoxide. Solvating alcohol in the hydrolysis products was confirmed by chemical analysis and IR spectroscopy of the products of their thermal decomposition. Residual carbon on thermal treatment in air is eliminated in two steps — at 300°C with formation of amorphous black powder and then in the process of crystallization at 400 to 500. A mixture of anatase and rutile is usually thus formed, calcination at higher temperature gives pure rutile. 

Polycrystalllne samples of LaSrAlCu05 were prepared by solid state reaction of Aldrich cupric oxide (99.999%), strontium carbonate (99.999%), lanthanum oxide (99.999%) and aluminum nitrate (99.999%). Powders were ground with a mortar and pestle and calcined In air at 950 C for 5 days with dally grindings. The product was dark black. Thermogravlmetrlc studies with a Du Pont Thermal Analysis System by reduction In hydrogen were used to determine the oxygen composition. 

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