Experimental Results and Theoretical Considerations on Thermogravimetric Decomposition Reactions of Chemical Compounds Under High Vacuum

Abstract

Investigations on thermogravimetric decomposition reactions under high vacuum have demonstrated that special attention should be paid to such factors as the sample size, the crucible form, the thickness of the layer in the crucible, and the particle size of the probe material. It is shown how the various influences can be eliminated by observing certain starting or test conditions. In addition to experiments on these specific influences, a comparison has been made of the degradation speeds of single crystals and crystal powders of chemical compounds.

Results which are complementary to the thermogravimetric measurements can be obtained with qualitative or quantitative determination of the gaseous decomposition products by mass-spectrometric analysis. From these measurements the course of decomposition was followed by recording the partial pressure at the various individual masses. This method is particularly suitable for the study of thermal degradations which produce more than one decomposition product in the same step.