Akira Taguchi^a, Mitsuhiro Inoue^a, Chikako Hiromi^a, Masaaki Tanizawa^a, Tomohito Kitami^b and Takayuki Abe^a

^aHydrogen Isotope Research Center, University of Toyama, Gofuku3190,Toyama 930-8555,Japan
^bNippon Pillar Packing Co.,Ltd., 541-1, Uchiba, Shimouchigami, Sanda, Hyogo 669-1333, Japan

Abstract

   The transition of Pt from a nanoparticle to a film on SiO₂ particles modified by the sputtering system with barrel-type powder sample holder(the barrel sputtering system). X-ray diffraction(XRD) and scanning electron microscopy(SEM) measurements reveal that the Pt nanoparticles grow in size with an increase in the duration of sputter deposition.The morphology of Pt changes from highly dispersed nanoparticles to a worm-like structure followed by a continuous Pt film, depending on the amount of Pt modified. Transmission electron microscopy(TEM) measurements reveal that the thin Pt film in the worm-like structure has a uniform thickness of approximately 2.6 nm, indicating film growth in a two-domensional mode followed by an island mode.

Key words: Barrel sputtering system, Surface coating, Environment friendly process

Satoshi Akamaru, Hironari Yamamoto and Takayuki Abe

Hydrogen Isotope Research Center, University of Toyama, Gofuku3190, Toyama 930-8555, Japan

Abstract

    We studied the coating of microparticles with tungsten carbide using a sputtering system with barrel-type powder sample holder(the barrel sputtering system). In order to find suitable sputtering conditions using the system, tungsten carbide was coated on a glass plate under various desired methane fractions, total pressures and RF powers. according to the XRD analysis on the fabricated films, the desired parameter is attained at a methane fraction of 5%, a total pressure of 1.5 Pa, and an RF power of 100 W. Surface coating of polymer microparticles with a WC layer was performed under this condition. Scanning electron microscope and energy-dispersion X-ray spectrum measurement show that the surface of the microparticle is uniformly coated with a thin WC layer.

Keywords: barrel sputtering system, coating, tungsten carbide, powder

Mitsuhiro Inoue, Satoshi Akamaru, Akira Taguchi, Takayuki Abe

Hydrogen Isotope Research Center, University of Toyama, Gofuku3190, Toyama 930-8555, Japan

Abstract

    The present study investigated physical and electrochemical properties of carbon-supported Pt-Ru alloy (Pt-Ru/C) samples prepared on various carbon supports by using a sputtering system with barrel-type powder sample holder(the barrel sputtering system). For this system, the deposited Pt-Ru nano-particles had uniform size of less than 4 nm and homogenerous atomic ratios of Pt and Ru of ca. 50:50 at.% independent of a specific surface area of the carbon support. Further, the electrochemical properties of the prepared samples obtained from CO stripping voltammetry were almost identical. These were completely different from the result for wet process showing that the physical and electrochemical propeties of samples prepared by an impregnation method changed with the specific surface area of the carbon support.

Key words: barrel sputtering system, polymer electrolyte fuel cells(PEFCs), anode electrocatalyst, physical and electrochemical properties, specific surface area of carbon support

Masanori Hara^a, Naomi Hatakeyama^b, Satoshi Akamaru^a, Kuniaki Watanabe^a, Katsuhiko Nishimura^b, Katsunori Mori^b , Masao Matsuyama^a

^aHydrogen Isotope Research Center, University of Toyama, Gofuku3190,Toyama 930-8555,Japan
^bFaculty of Engineering, University of Toyama, Gofuku3190,Toyama 930-8555,Japan

Abstract

   The magnetization of GdCu induced by hydrogen uptake was measured within the temperature range of 4.2 to 300 K, occurring phase changes were followed by X-ray diffraction measurements at ambient temperature. The prepared GdCu powder of CsCl-type structure readily absorbed hydrogen at ambient temperature, where hydrogen pressure was below 100 kPa. Hydrogenation changed the magnetism of GdCu in a complex manner from an antiferromagnetic-like type to a paramagnetic-like one. The changes in magnetic properties of GdCu by hydrogenation are governed by hydrogen-induced disproportionation. Within the composition range 0 <[H]/[GdCu]<1, GdCu disproportionated according to 2GdCu+H₂→GdH₂+GdCu₂ . The magnetization was evaluated by the expression χ_total=(1-x)χ_GdCu+(x/2)(χ_GdH2+χ_GdCu2). GdCu hydride was not observed. Hydrogenation beyond [H]/[GdCu]> 1 gave rise to the disproportionation of GdCu₂ causing the change in magnetization.

Key words: Gadolinium copper compound; Hydrogen; Disproportionation; Gadolinium hydride

田辺哲朗、松山政夫¹、大矢恭久 ²、永田晋二 ³、落合謙太郎 ⁴

九州大学大学院総合理工学研究院、 ¹富山大学水素同位体科学研究センター、
²静岡大学理学部附属放射科学研究施設、
³東北大学金属材料研究所、⁴日本原子力研究開発機構

Abstract

   材料中のトリチウム分布を知る手法としてトリチウムルミノグラフ、β線誘起Ｘ線計測法、二次イオン質量分析法、 イオンビーム核反応および弾性反跳粒子検出法についてその概要と測定例を紹介する。これらの手法には、トリチウムのみを検出できる方法や トリチウムを含む水素同位体すべてを原理的に測定できる手法があるが、材料中のトリチウム濃度に大きく依存するとともに、それぞれの分析法が それぞれの特徴を持っているので適切な分析手法の選択が必要である。

Key words: tritium distribution, tritium depth profile, IP, BIXS, SIMS, ERDa,NRa

Y.Oya, Y.Torikai¹

Radiochemistry Research Laboratory, Shizuoka University, 36 Ohya, Suruga-ward, Shizuoka 422-8059, Japan, ¹Hydrogen Isotope Research Center, University of Toyama, Gofuku3190, Toyama 930-8555, Japan

No Abstract

Key words: hydrogen isotope retention, thermal desorption spectroscopy(TDS), liquid scintillation counter(LSC)

S.Fukada, Y.Hatano¹, M.Hara¹

Interdisciplinary Graduate School of Engineering Sciences, Kyushu University, 6-1 Kasuga-kouen Kasuga, Fukuoka, Japan 816-8580
¹Hydrogen Isotope Research Center, University of Toyama, Gofuku3190, Toyama 930-8555, Japan

No Abstract

Key words: tritium, transfer, height equivalent to a theoretical plate, separation factor, gas chromatographym, BIXS, ionization chamber, mass spectrometry

M. Matsuyama

Hydrogen Isotope Research Center, University of Toyama, Gofuku3,190, Toyama 930-8555, Japan

No Abstract

Takayuki Abe, Masaaki Tanizawa, Kuniaki Watanabe, Akira Taguchi

Hydrogen Isotope Research Center, University of Toyama, Gofuku3190,Toyama 930-8555,Japan

Abstract

   Highly dispersed Ru nanoparticles loaded on a TiO₂support (Ru/TiO₂(B)), which affects the hydrogenation of CO₂ to CH₄ (methanation), were prepared by employing a "dry" modification method using a barre-sputtering instrument. The loaded Ru nanoparicles exhibited a narrow particlesize distribution with a mean diameter of ca. 2.5 nm. Methanation of CO₂ on the Ru/Tio₂(B) catalyst produced a lOO% yield at ca. 160℃, which is more than 200℃ below that required for Ru/TiO₂ prepared by a conventional "wet" impregnation method. ln addition, the methanation reaction over Ru/TiO₂(B) proceeded at temperatures as low as room temperature with a reaction rate of 0.04 υmol min^-1g^-1.

Masanori Hara, Yukiko Hayashi, Kuniaki Watanabe

Hydrogen Isotope Research Center, University of Toyama, Gofuku3190, Toyama 930-8555, Japan

Abstract

    The absorption of hydrogen by Zr₂Cu was studied by the aid of the Zr₂ Cu-H phase diagram elaborated by Kadel and Weiss. It was found that Zr₂Cu hydride was formed at ambient temperature after moderate hydrogen absorption. Hydrogen-induced disproportionation of Zr₂Cu occurred at temperatures exceeding 550 K. The unknown compound of the phase γ reported by Kadel and Weiss was identified as Zr₇Cu₁₀. It was also found that the β phase consisted of ZrCu and Zr hydride instead of Zr₂CuH_{x, x = 1.0-1.4}. The disproportionation behavior was found to follow a different mechanism below and above 973 K. Below 973K the disproportionation was found to proceed by the reaction sequence, Zr₂Cu+H₂→Zr₇Cu₁₀ + ZrH_x +H₂(γ phase) →Zr₁₄Cu₅₁ + ZrH_x +H₂(δ phase), and above 973K via the sequence, Zr₂Cu+H₂→ZrCu + ZrH_x +H₂(β phase) →Zr₇Cu₁₀ + ZrH_x +H₂(δ phase). The difference could be explained by the thermodynamic stability of ZrCu intermetallic compounds.

Y. Hatano^a, H. Hommaa^a, T. Sakamura^b, H. Saitoh^b, T. Nagasaka^c, T. Muroga^c, M. Matsuyama^a

^a Hydrogen Isotope Research Center, University of Toyama, Gofuku 3190, Toyama 930-8555, Japan
^b Department of Materials Science and Engineering, Muroran Institute of Technology, Muroran 050-8585, Japan
^c National Institute for Fusion Science, Toki 509-5292, Japan

Abstract

    Distribution of hydrogen isotopes was examined by tritium radioluminography using imaging plates for specimens of a V-4Cr-4Ti alloy prepared from two different plates fabricated with cold rolling under two different conditions (93% and 96% reduction in thickness) and recrystallization annealing. Influence of hydrogen on impact strength was also studied. Radioluminographs showed that tritium was concentrated in band-like regions where Ti(C,N,O) precipitates were densely distributed. The extent of tritium accumulation in the band-like regions and their shapes, however, were different between the two types of specimens; the band-like regions were thinner and more elongated, and the trapping effects of precipitates was smaller for the specimen prepared with higher extent of cold working. On the other hand, this type of specimen showed lower susceptibility to hydrogen embrittlement. These observations indicated that precipitate distribution prepared with higher extent of cold working is preferable to provide better durability against hydrogen embrittlement.

YAMANISHI Toshihiko¹，HAYASHI Takumi¹，IWAI Yasunori¹， ISOBE Kanetshugu¹，HARA Masanori²，SUGIYAMA Takahiko³， OKUNO Kenji⁴

Keywords : tritium confinement, tritium water, chemical properties, organic compounds

HATANO Yuji¹，TORIKAI Yuji¹，OYA Yasuhisa²,ODA Takuji³， TANAKA Satoru,³，中村博文⁴， ASAKURA Yamato⁵，OHUCHI Hiroko⁶，
OTSUKA Teppei⁷，KOBAYASHI Kazuhiro⁴

Keywords : tritium, permeation, contamination,, decontamination, surface, oxide, film, coating, water, diffusion. multl-scale modellng

Mitsuhiro Inoue^a, Toshiharu Nishimura^b, Satoshi Akamaru^b, Akira Taguchi^b, Minoru Umeda^aand Takayuki Abe^b
aDepartment of Materials Science and Technology, Faculty of Engineering, Nagaoka University of Technology, Kamitomioka 1603-1, Nagaoka, Niigata 940-2188, Japan
^bHydrogen Isotope Research Center, University of Toyama, Gofuku 3190, Toyama 930-8555, Japan

Abstract

    The CO oxidation on non-alloyed Pt and Ru electrocatalysts prepared by the polygonal barrel-sputtering method was investigated. Samples were prepared by sputtering Pt and Ru separately at room temperature. From the X-ray diffraction (XRD) measurement of the sample prepared on a SiO₂ glass plate, it was found that the sputtered metals are non-alloyed. Subsequently, the non-alloyed Pt and Ru electrocatalysts were prepared by the polygonal barrel-sputtering method using carbon powder as a support. The XRD patterns of these samples showed a single and very broad peak supporting the hypothesis of the non-alloyed Pt and Ru. No separate Ru reflections were visible, which could be attributed to Ru particle sizes smaller than 4 nm, as obtained by transmission electron microscopy (TEM). CO oxidation on the non-alloyed Pt and Ru electrocatalysts were evaluated by CO stripping voltammetry. This measurement revealed that the lower peak potential of CO oxidation varies, depending on the Pt content and the sputtering order. In addition, it was assumed that the CO oxidation reaction site for non-alloyed Pt and Ru electrocatalyst has a limited area including direct contact sites between the Pt and Ru particles.

Keywords: CO oxidation; Non-alloyed Pt and Ru electrocatalyst; Polymer electrolyte fuel cells; Anode catalyst; Polygonal barrel-sputtering method