Influence of texture and microstructure on the reactivity of aluminum powders

Aluminum powders are commonly used in energetics materials and it is possible to improve their reactivity by preparing them as nanopowders. In this article, it is shown that high-energy ball milling can be used to tune the reactivity of nanoflakes. Several nanopowders are synthesized using three different grinding ball diameters (5 mm, 10 mm and 15 mm). The powders are characterized in terms of morphology, structure and microstructure. Changing the diameter of the grinding balls results in powders with different characteristics. Among the three diameters used, an optimum is found for powders synthetized with 10 mm diameter balls: they possess the highest specific area, the smallest aluminum crystallites and the lowest amount of deformation. The reactivity of the various nanopowders, evaluated using thermal analysis under air, is shown to be dependent on both textural and microstructural properties of the powders. Such considerations on the microstructural properties of nanopowders are of utmost importance in the quest for the best materials for energetics applications.