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Kumar S.,Fusion Reactor Materials Section | Kumar S.,Hiroshima University | Singh A.,Hiroshima University | Jain U.,Fusion Reactor Materials Section | Dey G.K.,Fusion Reactor Materials Section
Fusion Engineering and Design | Year: 2015

Terminal solid solubility of hydrogen in Ta-Zr alloys has been studied in connection with the development of tantalum based metallic membrane for hydrogen/tritium purification. The alloys were prepared by vacuum arc melting technique and subsequently cold rolled to 0.2. mm thickness. The terminal solid solubility of hydrogen in these cold rolled samples was investigated in a modified Sieverts apparatus. The terminal solid solubility of hydrogen was marginally increased with zirconium content. The change in the lattices parameter of tantalum upon zirconium addition and the higher affinity of zirconium for hydrogen as compared to tantalum could be the possible reasons. © 2015 Elsevier B.V.

Sahayam A.C.,National Center for Compositional Characterisation of Materials | Das C.,Fusion Reactor Materials Section
Atomic Spectroscopy | Year: 2012

A method has been developed for the separation of Pb from trace impurities such as Nb, Ni, Sb, Sn, Ta, and Ti for their determination in Pb, PbLi, and PbBi alloy samples. Lead was separated as chloride fluoride (PbClF) precipitate. The method also enables the determination of hydrolyzable elements which are otherwise not recovered. The separation of Pb was found to be 99.5%, whereas the recovery of impurities was in the 82-94% range. Matrix-free solutions were analyzed for Nb, Ni, Sb, Sn, Ta, and Ti by inductively coupled plasma optical emission spectrometry (ICP-OES). The method was applied for the analysis of Pb, PbLi, and PbBi alloy samples. Relative standard deviations were in the 1.8-10.2% range and the process blank levels were at the lower ug/g level.

Kumar S.,Fusion Reactor Materials Section | Tiwari G.P.,Ra Institute Of Technology | Krishnamurthy N.,Fusion Reactor Materials Section
Journal of Alloys and Compounds | Year: 2015

Abstract Vanadium could be a potential candidate for on board hydrogen storage application because of its high gravimetric hydrogen storage capacity (∼3.8 mass%) which is even better then the most widely explored AB5, AB2 & AB intermetallic compounds. Hydrogen absorption of vanadium takes place at ambient temperature and pressure with fast kinetics. The vanadium hydride (VH2) releases hydrogen in two steps: (1) VH2(γ)(s) 虠 V2H(β)(s) and (2) V2H(β)(s) 虠 2V(s) + 1/2 H2(g). First step is achievable at the ambient temperature and pressure conditions while, the second step requires high temperature (590 K). Thus only half of the total hydrogen storage capacity is available for use on subsequent absorption-desorption cycles at the ambient temperature. The usable hydrogen storage capacity of VH2 at ambient conditions could be enhanced by tailoring the thermodynamics and kinetics of second step of hydrogen desorption reaction. This could be possible by selecting suitable alloy additives. The present study deals with the selection criteria of alloy additives based on the electronic consideration to tailor the hydrogen desorption thermodynamics and kinetics of V2H. © 2015 Elsevier B.V.

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