Effects of ball milling conditions and additives on the hydrogen sorption properties of Mg+5wt.Cr2O3 mixtures.

摘要

The influence of the mechanical grinding (under reactive atmosphere of hydrogen)conditions on the physico-chemical properties (crystallographic, phase composition,morphology and hydrogen sorption properties) of a Mg+5wt.%Cr2O3 mixture are examined.The planetary ball mill allows to obtain finer particules and more amorphous materials. Therelationship between crystallinity, morphology, injected power and sorption properties wasestablished. The highest desorption rates at 300°C obtained is 1.32 .10-2 wt.%/s (planetary ballmiller, 300rpm, 34 balls and 8 g of powders). Finally, nano-Cr2O3 synthesized by Super CriticalFluid process was used as an additives and then in the same milling conditions, the desorptionrate at 300°C increases to 2.37 .10-2 wt.%/s and is correlated with the presence of nano-Cr metalin the mixture.