Suppressed Hydrogen (H) Solubility in Body Centered Cubic Vanadium (V) by Alloying with Molybdenum (Mo), Chromium (Cr), Iron (Fe) or Cobalt (Co) Appreciated in Terms of Statistical Thermodynamics

Autor: Nobumitsu Shohoji
Rok vydání: 2016
Předmět:
Zdroj: Repositório Científico de Acesso Aberto de Portugal
Repositório Científico de Acesso Aberto de Portugal (RCAAP)
instacron:RCAAP
ISSN: 1347-5320
1345-9678
Popis: Equilibrium isothermal pressure-composition relationships reported for H solubility in body centered cubic (bcc) V11yMyHx (M = Cr, Mo, Fe or Co) by Suzuki et al. recently on this journal were analyzed with statistical thermodynamics under a priori assumption of constant H-H interatomic interaction energy E(H-H) within homogeneity composition range of bcc V11yMyHx phase at arbitrary temperature T. Results of the present statistical thermodynamic analysis showed that detected H solubility suppression for the examined V11yMyHx was consistently interpreted in terms of decrease of available number a for occupation by H atoms per metal atom in the V11yMy lattice from a = 0.55 determined for bcc VHx in the earlier work of the author. The extent Q of stabilization of H atoms in the V11yMy lattice through formation of H-V and H-M bonds was one of principal parameters determined by the statistical thermodynamic analysis. It was intriguing to note that Q(V11yMyHx) with M = Fe and Co became less negative than Q(VHx) in pure bcc VHx implying that the extent of stabilization of H atoms in V11yMy lattice with M = Fe or Co increased with reference to that in pure VHx in spite of decreased a from that (0.55) in VHx. On the other hand, Q(V11yMyHx) with M = Cr and Mo became less negative (that is decreased stability of H) than Q(VHx) corresponding straightforwardly to the detected decrease of a value from that in VHx. Noting the promoted H permeability reported for V11yFey membrane by Suzuki et al., search for alloying element M that induced H solubility drop form that in the bcc V but with effect of enhancing stability of H in the V11yMy lattice was concluded to be a pragmatic guideline for the screening of alloying constituent towards development of V-based H permeation membrane material. [doi:10.2320/matertrans.M2015415]
Databáze: OpenAIRE