| Summary: | 碩士 === 逢甲大學 === 材料科學所 === 97 === In recent years, many dramatic researches were concerned with metalhydrides. Metal hydrides provide a safe storage and/or carrier of thehydrogen. Using hydrogen storage alloys to store and transport hydrogenis a newly developed technique with the advantages of relatively small volume, low pressure and high safety. Among various hydrogen storagealloys, Mg-based alloy is promising due to its merits such as high hydrogen capacity, light weight and low cost.In this study ZK60 alloy (Mg-6 wt%Zn-0.8 wt%Zr) was used as a hydrogen storage materials. The hydrogen storage properties related with crystal structure, kinetic curves at different absorption/desorption temperatures and cyclic behavior were investigated. Experimental results
show that the activation behavior of the ZK60 alloy with cold rolled process is relatively difficult, even for ZK60 alloy powders with 20 hr ball-milling treatment. The hydrogen capacity can’t reach its maximum value yet after 10 cycles of hydrogen absorption/desorption. In order to
improve this drawback, small amounts of graphite were added to ZK60 alloy. The alloy with graphite addition exhibits an excellent performance just after the first cycle of hydrogen absorption/ desorption. In addition,
the amount of strains, ball mill time and graphite amount play important roles to improve its hydrogen storage properties. Increasing strains can improve the activation property of the ZK60 alloy. ZK60 alloy with 5 wt% graphite addition and 20 hr ball-milling treatment exhibits the best
properties. The maximum hydrogen storage capacity of the alloys is 6.60 wt%, and it can reach 80% of the maximum hydrogen capacity after 5minutes. After 100 cycles of absorption/desorption, the hydrogen capacity is reduced 1.2 wt%, and the alloys exhibit better cyclic stability and
maintain 5.41 wt% hydrogen capacity.
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