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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

An alternative route to produce easily activated nanocrystalline TiFe powder

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Author(s):
Falcao, R. B. [1] ; Dammann, Edgar D. C. C. [1] ; Rocha, C. J. [1] ; Durazzo, M. [2] ; Ichikawa, R. U. [1] ; Martinez, L. G. [1] ; Botta, W. J. [3] ; Leal Neto, R. M. [1]
Total Authors: 8
Affiliation:
[1] Nucl & Energy Res Inst, Mat Sci & Technol Ctr, IPEN CNEN SP, Av Prof Lineu Prestes 2242, BR-05508000 Sao Paulo, SP - Brazil
[2] Nucl & Energy Res Inst, IPEN CNEN SP, Nucl Fuel Ctr, Av Prof Lineu Prestes 2242, BR-05508000 Sao Paulo, SP - Brazil
[3] Univ Fed Sao Carlos, Mat Engn Dept, Rod Washington Luiz, Km 235, BR-13565905 Sao Carlos, SP - Brazil
Total Affiliations: 3
Document type: Journal article
Source: INTERNATIONAL JOURNAL OF HYDROGEN ENERGY; v. 43, n. 33, p. 16107-16116, AUG 16 2018.
Web of Science Citations: 3
Abstract

In this paper, an alternative process route to produce active nanocrystalline TiFe compound was investigated. First, TiH2 and Fe powders were dry co-milled in a planetary ball mill for 5-40 h. TiH2 was selected as precursor powder, instead of Ti powder, due its fragility, which has proved to be beneficial to decrease powders adherence on milling tools. In terms of loose powder mass, milling yields ranged from 90 to 95 wt.%. Next, milled powders were post-heated at 873 K under dynamic high-vacuum for TiFe synthesis reaction. First hydrogen absorption was verified in situ during the cooling process of samples (until the room temperature), being the amount of hydrogen absorbed and desorbed by this samples measured by automated Sievert's apparatus, under constant hydrogen flow rate of 9 cm(3). min(-1) (dynamic measurements). Besides to allowing the first absorption in situ, the investigated process route also allowed the production of the non-stoichiometric TiFe compound (rich in Ti) in samples milled for shorter times (5 and 10 h), both characteristics associated with maintaining the mechanical compound activity. Each sample absorbed hydrogen at 2 MPa during the cooling process, requiring no additional thermal activation cycles, since the samples milled for shorter times (mainly for 10 h) could absorb hydrogen for the first time more easily. However, the samples milled for longer times (25 and 40 h) shown better results in terms of reversible and storage capacities (0.73 and 0.94 wt.%, respectively). (C) 2018 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved. (AU)