BALL-MILLED HYDROGEN STORAGE IN Mg-Cu – BASED ALLOYS MODIFIED BY KCl: DISTRIBUTION OF COMPONENTS

Magnesium and its alloys is a class of materials, which is still one of the most prospective hydrogen storage (HS) compositions. This is due before all to their high hydrogen sorption capacity and low cost. However, pure Mg must be alloyed with other elements to suppress the tendency to Mg oxidation and to improve the otherwise lazy ab/desorption kinetics and to decrease the operation temperature. Also some modifiers, as e.g., hall elements and alkali metals, are known to enhance the HS characteristics. It is known that sorption performance can be further substantially enhanced by nanosizing. This paper is devoted to study of distribution of components in Mg-xCu alloys (x = 9.94 – 21.56 wt%) prepared by high-energy ball-milling (BM). Elements K and Cl – as modifiers – were introduced by BM of the Mg-Cu base with addition of KCl. It was found that KCl decomposed partly into elements, which entered grains of milled blend. Chlorine anions entered preferentially the Mg-rich regions.