Modelling powder compaction and mixture laws

The purpose of this paper is related to the improvement of the manufacturing processes of pyrotechnic compositions by determining the relative influence of physical properties on the compressibility and the cohesion. The Heckel-Gonthier four parameter model is used to assess the powder compressibility. This relationship is generally applied to the compression of pharmaceutical powders, but we show a good correlation with the behaviour of pyrotechnic compositions. The compact cohesion is assessed by the cohesion index and the breaking resistance. This study demonstrates that the mean diameter, generally used as a parameter to describe the particle size, is less reliable than the dispersion index. This approach makes it possible to formulate mixing behaviour laws that can reduce the required number of experiments to assess a new composition.