2018 - Sustainable Industrial Processing Summit & Exhibition
4-7 November 2018, Rio Othon Palace, Rio De Janeiro, Brazil
| Severe Plastic Deformation for Production of High-performance Hydrogen Storage Materials Zenji Horita1; 1KYUSHU UNIVERSITY, Fukuoka, Japan; PAPER: 271/SISAM/Keynote (Oral) SCHEDULED: 15:55/Mon./Copacabana A (150/1st) ABSTRACT: High performance of hydrogen storage requires not only fast absorption/desorption kinetics but also lower operating temperature near ambient pressure. A process of severe plastic deformation through high-pressure torsion (HPT) was applied to two major hydrogen storage metallic materials such as Ti-based and Mg-based systems. Microstructures were well refined by the HPT process, so that nanograins were formed in the materials. For the Ti-based system, an HPT-processed TiFe intermetallic no longer requires pre-activation that limits practical use, as it involves exposure to hydrogen atmosphere under high pressures (>3 MPa) at high temperatures (~700 K). The lack of requirement for pre-activation is because hydrogen diffusion is enhanced through introduction of high densities of lattice defects such as grain boundaries [1]. Furthermore, the HPT-processed TiFe was not deactivated even after storage in air [2]. Application of the HPT process to Mg<sub>2</sub>Ni made its hydrogen storage performance improved so that hydrogen absorption is feasible at a reduced temperature of 423 K with faster hydrogen kinetics. This was due to the introduction of high densities of planar lattice defects such as grain boundaries and stacking faults [3]. References: [1] K. Edalati, J. Matsuda, H. Iwaoka, S. Toh, E. Akiba, Z. Horita, Int. J. Hydrogen Energy 38 (2013) 4622-4627. [2] K. Edalati, J. Matsuda, M. Arita, T. Daio, E. Akiba, Z.Horita, Appl. Phys. Lett. 103 (2013) 143902. [3] T. Hongo, K. Edalati, M. Arita, J. Matsuda, E. Akiba, Z. Horita, Acta Mater. 92 (2015) 46-54. |
