PROPERTIES OF MAGNESIUM ALLOYS FOR HYDROGEN STORAGE

The method of hydrogen storage is a key problem in hydrogen economy. Storing of hydrogen in the form of metal hydrides seems to be very prospective. In the first part of this work, as-cast binary MgMm20 and ternary MgNi10Mm5, MgNi10Cu5 and MgNi23P0.3 alloys were exposed to electrochemical hydriding in a 6 mol/l KOH solution at ambient temperature for 16 hours. The best hydriding efficiency is achieved by the ternary MgNi10P0.3 and MgNi10Mm5 alloys, namely about 0.2 wt. %. The second part of paper deals with an evaluation of hydrogen diffusion coefficients in the pure Mg and alloys which were subjected to electrochemical hydriding. The lowest diffusion coefficient of hydrogen was determined in pure Mg and MgNi10Mm5 alloy. The highest one (1.1·10 -10 m 2 /s) corresponds to MgNi10Cu5. Microstructure of alloys was described and its influence on both the ability to absorb hydrogen and the diffusion coefficients is discussed.