| Summary: | 碩士 === 遠東科技大學 === 機械工程研究所 === 99 === The study aims to investigate the effect of fixed polarities with different electrode materials, discharge currents and pulse duration on the structural and hydrogen storage properties of hydrogen storage alloy powders prepared by means of electrical discharge alloying (EDA). Experimental results reveal that powder prepared with nickel as the cathode appears mostly spheroidal and only a small part appears broken and irregular while the same prepared with magnesium as the cathode appears mostly broken and irregular. Both powders have cracks and pores that occurred during the EDA on the surface.
Results of analysis using ICP and EDS show that powders prepared with nickel and magnesium as the cathode both contain Mg and Ni while the same prepared with magnesium as the cathode contains considerably little Ni. Results of analysis using XRD further reveals that powder prepared with nickel as the cathode mainly contains Mg2Ni, MgNiO2, MgNi2, Mg6Ni, Mg and Ni phases while the same prepared with magnesium as the cathode contains Mg2Ni, MgNiO2, MgNi2, Mg6Ni and Mg phases prior to hydrogen absorption. The main phases of both powders are Mg2NiH4, Ni2H, MgNiO2 and Mg4NiO following hydrogen absorption. The same results confirm that powders prepared using EDA are capable of absorbing hydrogen.
Results of hydrogen storage testing indicate that powder prepared with nickel as the cathode is significantly more capable of absorbing hydrogen compared with the same prepared with magnesium and powder prepared with low discharge current has a better capability of hydrogen absorption compared with the same prepared with high discharge current. To sum up the aforementioned results, the content of Ni in hydrogen storage alloy powders affects hydrogen storage.
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