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Preparation of V-based Alloy Membranes using Chemical Transport Process

Published online by Cambridge University Press:  11 February 2011

Tetsuya Ozaki
Affiliation:
Ecomaterials Center, National Institute for Materials Science, Sengen 1–2–1, Tsukuba, Ibaraki 305–0047, Japan
Yi Zhang
Affiliation:
Ecomaterials Center, National Institute for Materials Science, Sengen 1–2–1, Tsukuba, Ibaraki 305–0047, Japan
Masao Komaki
Affiliation:
Ecomaterials Center, National Institute for Materials Science, Sengen 1–2–1, Tsukuba, Ibaraki 305–0047, Japan
Chikashi Nishimura
Affiliation:
Ecomaterials Center, National Institute for Materials Science, Sengen 1–2–1, Tsukuba, Ibaraki 305–0047, Japan
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Abstract

Novel preparation process of V-Ni alloys for hydrogen purification membrane using chemical transport was investigated. Vanadium, NH4Cl, and PtCl2 as evaporating source were put in one side of a fused-silica tube, and Ni substrate was put in the other side. The fused-silica tube was sealed in vacuo, and set in a furnace with temperature gradients. Evaporating source temperature was 1173–1273 K. Substrate temperature was 3–100 K higher than the evaporating source temperature. This process consists of formation of HCl from NH4Cl and PtCl2, chemical transport of vanadium under temperature gradient via chlorides in the presence of HCl, and diffusion of the transported V into the Ni substrate. EDX line profile of cross section of the substrates after the process demonstrated that V diffused into the Ni substrates. Distribution of V concentration in the substrates was dependent on the substrate temperature and the temperature difference between the substrate and the evaporating source. Heating condition was optimized to obtain homogeneous V-Ni alloy. When the substrate temperature and evaporating-source temperature were 1228 K and 1223 K, respectively, V diffused homogeneously into the Ni substrate with thickness of 20 μm, and V concentration attained in the substrate was higher than 70at%.

Type
Research Article
Copyright
Copyright © Materials Research Society 2003

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References

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