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송명엽,곽영준,Seong Ho Lee,박혜령,Byoung-Goan Kim 대한금속·재료학회 2013 METALS AND MATERIALS International Vol.19 No.4
In a shift from prior work, MgH2, instead of Mg, was used as a starting material in this work. A sample with a composition of 86 wt% MgH2-10 wt% Ni-4 wt% Ti was prepared by reactive mechanical grinding. Activation of the sample was completed after the first hydriding cycle. The effects of reactive mechanical grinding of Mg with Ni and Ti were discussed. The formation of Mg2Ni increased the hydriding and dehydriding rates of the sample. The addition of Ti increased the hydriding rate and greatly increased the dehydriding rate of the sample. The titanium hydride, TiH1.924, was formed during reactive mechanical grinding. This titanium hydride, which is brittle, is thought to help the mixture pulverized by being pulverized during reactive mechanical grinding and further to prevent agglomeration of the magnesium by staying as a hydride among Mg particles. A rate-controlling step for the dehydriding reaction of the hydrided MgH2-10Ni-4Ti was analyzed by using a spherical moving boundary model on an assumption that particles have a spherical shape with a uniform diameter.
Song, Myoung Youp,Kwak, Young Jun,Lee, Byung-Soo,Park, Hye Ryoung,Kim, Byoung-Goan Elsevier 2012 INTERNATIONAL JOURNAL OF HYDROGEN ENERGY - Vol.37 No.2
<P><B>Abstract</B></P> <P>Ni, Fe<SUB>2</SUB>O<SUB>3</SUB>, and CNT were added to Mg. The content of the additives was about 20 wt % with that of Fe<SUB>2</SUB>O<SUB>3</SUB> 6 wt%. The contents of about 20 wt % additives and 6 wt% Fe<SUB>2</SUB>O<SUB>3</SUB> are known optimum ones to improve the reaction rates of Mg with H<SUB>2</SUB>. Samples with compositions of 80 wt% Mg–14 wt% Ni–6 wt% Fe<SUB>2</SUB>O<SUB>3</SUB> (named as Mg–14Ni–6Fe<SUB>2</SUB>O<SUB>3</SUB>), and 78 wt% Mg–14 wt% Ni–6 wt% Fe<SUB>2</SUB>O<SUB>3</SUB>–2 wt% CNT (named as Mg–14Ni–6Fe<SUB>2</SUB>O<SUB>3</SUB>–2CNT) were prepared by reactive mechanical grinding. The hydriding and dehydriding properties of these samples were then measured, and the effects of Ni, Fe<SUB>2</SUB>O<SUB>3</SUB>, and CNT addition on the hydriding and dehydriding rates of Mg-based alloys were investigated by comparing their hydrogen-storage properties with those of pure Mg and Mg–10 wt% Fe<SUB>2</SUB>O<SUB>3</SUB>.</P> <P><B>Highlights</B></P> <P>► Content of the additives of about 20 wt %, and 6 wt% of oxide addition. ► Preparation of Mg–14Ni–6Fe<SUB>2</SUB>O<SUB>3</SUB>, and Mg–14Ni–6Fe<SUB>2</SUB>O<SUB>3</SUB>–2CNTby RMG. ► Effects of Ni, Fe<SUB>2</SUB>O<SUB>3</SUB>, and CNT addition on hydriding and dehydriding rates. ► Addition of Ni and Fe<SUB>2</SUB>O<SUB>3</SUB> increases hydriding rate and/or dehydriding rate. ► CNT Addition made activation process unnecessary with a small decrease in capacity.</P>
Effect of CNT Addition on the Hydriding and Dehydriding Rates of Mg-Ni-Fe2O3 Alloy
( Myoung Youp Song ),( Young Jun Kwak ),( Byung Soo Lee ),( Hye Ryoung Park ),( Byoung Goan Kim ) 대한금속재료학회(구 대한금속학회) 2011 대한금속·재료학회지 Vol.49 No.12
Samples with compositions of 80 wt% Mg-14 wt% Ni-6 wt% Fe2O3 (named Mg-Ni-Fe2O3), and 78 wt% Mg-14 wt% Ni-6 wt% Fe2O3-2 wt% CNT (named Mg-Ni-Fe2O3-CNT ) were prepared by reactive mechanical grinding. Hydriding and dehydriding properties and effects of CNT addition on the hydriding and dehydriding rates of Mg-Ni-Fe2O3 were then investigated. Activation of the Mg-14Ni-6Fe2O3 sample was completed after three hydriding (under 12 bar H2)-dehydriding (under 1.0 bar H2) cycles at 573 K. The addition of CNT to the Mg-14Ni-6Fe2O3 sample made the activation process unnecessary, with a small decrease in the hydrogen-storage capacity.
Hydrogen Storage Properties of Hydriding-Dehydriding Cycled Magnesium-Nickel-Iron Oxide Alloy
( Myoung Youp Song ),( Sung Nam Kwon ),( Hye Ryoung Park ),( Byoung Goan Kim ) 대한금속재료학회 ( 구 대한금속학회 ) 2012 대한금속·재료학회지 Vol.50 No.2
By measuring the absorbed hydrogen quantity as a function of the number of cycles, the cycling properties of the Mg-15 wt%Ni-5 wt%Fe2O3 alloy were investigated. The absorbed hydrogen quantity decreased as the number of cycles increased. The Ha value varied almost linearly with the number of cycles. The maintainability of absorbed hydrogen quantity at n=100 was 89.0% for the hydriding reaction time of 10 min. After the 150th hydriding-dehydriding cycle, Mg, Mg2Ni, Mg(OH)2, MgO, and Fe were observed. The phases were analyzed by Rietveld analysis from the XRD patterns of the Mg-15 wt%Ni-5 wt%Fe2O3 alloy after 150 hydriding-dehydriding cycles. The crystallite size and strain of Mg were then estimated with the Williamson-Hall technique.
Hydrogen-Storage Properties of Li3N, LiBH4, Fe and/or Ti-Added Mg or MgH2
( Myoung Youp Song ),( Sung Nam Kwon ),( Young Jun Kwak ),( Hye Ryoung Park ),( Byoung Goan Kim ) 대한금속재료학회(구 대한금속학회) 2013 대한금속·재료학회지 Vol.51 No.8
In order to increase the hydrogen storage performance of Mg or MgH2-based materials, Li3N, LiBH4, Fe, and/or Ti were added. Mixtures with compositions of 50MgH2-50Li3N, 40Mg-10MgH2-50Li3N, 68MgH2-17LiBH4-15Fe, and 70MgH2-17LiBH4-13Ti were prepared by reactive mechanical grinding, and their hydrogen-storage properties were examined. 68MgH2-17LiBH4-15Fe and 70MgH2-17LiBH4-13Ti had higher hydriding rates than the Li3N-containing samples, 50MgH2-50Li3N and 40Mg-10MgH2-50Li3N, at 573 K under 12 bar H2. However, the dehydriding rates of 68MgH2-17LiBH4-15Fe and 70MgH2-17LiBH4-13Ti were as low as those of the Li3N-containing samples at 573 K under 1.0 bar H2. (Received December 18, 2012)