• Title/Summary/Keyword: Mg-Ti-Ni-H systems

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The Fabrication of MggTi1-(10, 20 wt%)Ni Hydrogen Absorbing Alloys by Hydrogen Induced Mechanical Alloying and Evaluation of Hydrogenation Properties(Part II : Evaluation of Pressure-Composition-Isotherm Properties) (수소 가압형 기계적 합금화법을 이용한 MggTi1-(10, 20 Wt%)Ni 수소저장합금의 제조와 수소화 특성 (제 2보 : 압력-조성-등온 특성 평가))

  • Hong, Tae-Whan;Kim, Gyeong-Bum;Kim, Yeong-Jig
    • Journal of Hydrogen and New Energy
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    • v.13 no.4
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    • pp.270-278
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    • 2002
  • Mg and Mg alloys are attractive hydrogen storage materials because of their lightweight and high absorption capacity. Their range of applications could be further extended if their hydrogenation properties and degradation behavior could be improved, The main emphasis of this study was to find an economic manufacturing method for Mg-Ti-Ni-H systems, and to investigate their hydrogenation properties, In order to examine hydrogenation behavior, a Sieverts type automatic pressure-composition-isotherm(PCI) apparatus was used and the experiments were performed at 423, 473, 523, 573, 623 and 673K. The results of thermogravimetric analysis(TGA) reveal that the absorbed hydrogen contents are around 2.5 wt% for ($Mg_9Ti_1$)-10 wt% Ni. With increased Ni content, the absorbed hydrogen content decreases to 1.7 wt%, whereas the dehydriding starting temperatures are lowered by some 70-100K. The results of PCI on ($Mg_9Ti_1$)-20 wt% Ni show that its hydrogen capacity is around 5.3 wt% and its reversible capacity and plateau pressure are also excellent at 523K and 573K. In addition, the reaction enthalpy, $\Delta$HD.plateau, is $30.6{\pm}5.7kJ/molH_2$.

The Fabrication of Mg9Ti1-(10, 20 wt%)Ni Hydrogen Absorbing Alloys by Hydrogen Induced Mechanical Alloying and Evaluation of Hydrogenation Properties (Part I : Preparations and Characterizations of Alloys) (수소 가압형 기계적 합금화법을 이용한 Mg9Ti1-(10, 20 wt%)Ni 수소저장합금의 제조와 수소화 특성 (제 1보 : 합금제조와 특성평가))

  • Hong, Tae-Whan;Kim, Gyung-Bum;Kim, Young-Jig
    • Journal of Hydrogen and New Energy
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    • v.13 no.3
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    • pp.197-203
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    • 2002
  • The main emphasis of this study was to find an new hydrogen absorbing alloy such as Mg-Ti-Ni-H systems, and to investigate their hydrogenation properties. ($Mg_9Ti_x$)-10, 20wt%Ni-Hx systems were prepared by hydrogen induced mechanical alloying(HIMA) using Mg and Ni chips and sponge Ti. The particles synthesized were characterized by X-ray diffraction, and their morphologies were observed by means of scanning electron microscopy(SEM) with energy dispersive spectrometry (EDS). In addition, the crystal structures were analyzed in terms of their bright-/ dark field images and the selected area diffraction pattern(SADP) of transmission electron microscopy(TEM).

Fabrication and Evaluation of Hydorgenation Propeties on Mg8Ti2-(10, 20 wt.%)Ni Composites (Mg8Ti2-(10, 20 wt.%)Ni 수소저장합금의 제조 및 수소화 특성 평가)

  • Kim, Kyeong-Il;Hong, Tae-Whan
    • Korean Journal of Materials Research
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    • v.20 no.10
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    • pp.543-549
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    • 2010
  • The hydrogen energy had recognized clean and high efficiency energy source. The research field of hydrogen energy was production, storage, application and transport. The commercial storage method was using high pressure tanks but it was not safety. However metal hydride was very safety due to high chemical stability. Mg and Mg alloys are attractive as hydrogen storage materials because of their lightweight and high absorption capacity (about 7.6 wt%). Their range of applications could be further extended if their hydrogenation properties and degradation behavior could be improved. The main emphasis of this study was to find an economical manufacturing method for Mg-Ti-Ni-H systems, and to investigate their hydrogenation properties. In order to examine their hydrogenation behavior, a Sievert's type automatic pressure-compositionisotherm (PCI) apparatus was used and experiments were performed at 423, 473, 523, 573, 623 and 673 K. The results of the thermogravimetric analysis (TGA) revealed that the absorbed hydrogen contents were around 2.5wt.% for (Mg8Ti2)-10 wt.%Ni. With an increasing Ni content, the absorbed hydrogen content decreased to 1.7 wt%, whereas the dehydriding starting temperatures were lowered by some 70-100 K. The results of PCI on (Mg8Ti2)-20 wt.%Ni showed that its hydrogen capacity was around 5.5 wt% and its reversible capacity and plateau pressure were also excellent at 623 K and 673 K.

Effect of NiO on Microstructure and Properties of PMN-PT-BT Ceramics Prepared by Mixed Oxide Method

  • Han, Kyoung-Ran;Jung, Jung-Woong;Kim, Chang-Sam
    • Journal of the Korean Ceramic Society
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    • v.41 no.12 s.271
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    • pp.884-888
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    • 2004
  • Effects of NiO were studied in aspects of dielectric properties and microstructure of $0.96(0.91Pb(Mg_{1/3}Nb_{2/3})O_3-0.09PbTiO_3)­0.04BaTiO_3$ (PMN-PT-BT, PBT). The PBT was prepared by a conventional mixed oxide method using $(MgCO_3)_4{\cdot}Mg(OH)_2$ instead of MgO through Lewis acid-base interaction. NiO was added in the range of 0.5 to $3.0\;wt\%$ as thermally decomposable $2NiCO_3{\cdot}3Ni(OH)_2$ and it seemed to enhance densification to a large extent below $1000^{\circ}C$. But all the systems gave rise to ceramics with almost same relative sintered density of 96% by sintering at $1000^{\circ}C$ for 2 h. But it turned out that the addition of NiO was detrimental to dielectric constant but beneficial to the loss of dielectric constant.