Palestra "Proposing design guideline for hydrogen permeation membrane alloy based on Va-group metals (V, Nb and Ta) taking into account atomic interaction energy parameter evaluated by statistical thermodynamics"

A palestra realizou-se no dia 11 de março de 2016, no Auditório Solar XXI, no Pólo do Lumiar

Orador: Nobumitsu Shohoji

Resumo:

Yukawa and his collaborators at Nagoya University investigated systematically hydrogen (H) absorption and permeation behaviors of membranes of alloys based on Va-group metals (V, Nb and Ta) possessing body centered cubic (bcc) lattice structure. They aimed at developing Va-group alloy A1-yMy with suppressed susceptibility to hydrogen embrittlement (HE) without sacrificing H permeation performance by alloying Va-group metal A (= V, Nb or Ta) with another metallic constituent M (= Cr, Mo, W, Ru, Fe or Co) possessing affinity to H weaker than that of Va-group metal to H. Yukawa and his co-workers identified some A1-yMy alloys as favourable H permeation membrane materials. The author carried out statistical thermodynamic analysis for the reported equilibrium pressure-temperature-composition (PCT) relationships for bcc A1-yMyHx by Yukawa and co-workers and evaluated parameter Q referring to extent of stabilization of H in A1-yMy alloy lattice. In this work, the author reviewed correlation between the Q parameter values estimated by statistical thermodynamic analysis and the reported H permeation performances with hope of proposing simple pragmatic guideline for screening bcc A1-yMy alloy membrane possessing favourable H permeation performance among candidate materials. The review result indicated that alloying element M that leads to suppressed H solubility in bcc A1-yMy lattice but realizes increased extent of stability for H in A1-yMyHx lattice (i.e. Q(A1-yMyHx) < Q(AHx)) must be considered as the preferred alloying element in view of improved H permeation performance. Then, susceptibility to HE must be evaluated experimentally for thus-screened group of A1-yMy alloy membranes by H permeation test. Such primary screening process of A1-yMy on the basis of equilibrium PCT data would contribute towards reducing number of desired kinetic H permeation experimental test runs on selection of favourable A1-yMy alloy membrane material from candidate alloys.

Nota biográfica:

Nobumitsu Shohoji

1949.07.18 born in Okayama (Japan),

1956.04-1962.03: Takaha Elementary School (Kobe),

1962.04-1965.03: Takasho Junior High School (Kobe),

1965.04-1968.03: Kobe High School,

1968.04-1972.03: Osaka University, Faculty of Engineering, Department of Nuclear Engineering,

1972.04-1974.03: Garduate School of Osaka University (Master Course), Department of Nuclear Engineering,

1974.04-1977.03: Graduate School of Osaka University (Doctor Course), Department of Nuclear Engineering,

1977.09-1978.12: KfK - Kernforschungszentrum Karlsruhe, IMF - Institut für Material- und Festkörperforschung, West Germany; Gastwissenschaftler,

1979.02-1982.05: University of Sheffield, Department of Metallurgy; IRW (Independent Research Worker; post-doctoral researcher),

1982.07 - to date: LNEG - Laboratório Nacional de Energia e Geologia; Researcher

1988.10: promoted to Investigador Principal (Principal Researcher)

1999.04: promoted to Investigador Principal com Habilitação

2004.08: promoted to Investigador Coordenador (Research Coordinator)

2015.06: received "Prémio de Carreira e Reconhecimento" from SPMater (Sociedade Portuguesa de Materiais)

With 3 major lines of research interests

  1. Statistical thermodynamic analysis of non-stoichiometric interstitial compounds,
  2. Synthesis of carbide, nitride and carbo-nitride (including usage of concentrated solar beam as the reaction heat source as well as usage of conventional electric furnace),
  3. Formation and characterisation of non-equilibrium solid phases.

Destinatários:

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Data e hora:

11 de março de 2016 das 10:15h às 11:15h.

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