Consistent description of hydrogen permeation through metal membrane based on hydrogen chemical potential and its applic
- PDF / 995,452 Bytes
- 12 Pages / 584.957 x 782.986 pts Page_size
- 100 Downloads / 266 Views
A consistent description of the hydrogen permeation through metal membrane based on hydrogen chemical potential proposed has been explained in detail. The hydrogen flux is proportional to the PCT factor, fPCT, consistently, which reflects the shape of the pressure-composition-isotherm (PCT curve) of the material. In addition, in view of the PCT factor, fPCT, and the ductile-to-brittle transition hydrogen concentration, DBTC, a concept for alloy design with high hydrogen permeability and strong resistance to hydrogen embrittlement has been proposed. In this concept, it is important to design alloy composition with appropriate PCT curve under the given pressure and temperature condition. As an example, V–9 mol% Al alloy has been designed, which exhibits high hydrogen flux without brittle fracture under given condition. Thus, the new consistent description is useful not only for the understanding of the hydrogen permeation property but also for the alloy design. In March 2013, Asuka Suzuki took a bachelor’s degree of engineering at Nagoya University. In April 2013, he went on to the master’s course of Graduate School of Engineering in Nagoya University. In March 2015, he took a master’s degree of engineering at Nagoya University. In April 2015, he went on to the doctoral course of Graduate School of Engineering in Nagoya University. In September 2016, he took a doctor’s degree of engineering at Nagoya University. Currently, he is a Research Fellow of Japan Society for the Promotion of Science (PD) in Nagoya University.
Asuka Suzuki
I. INTRODUCTION
The hydrogen permeable alloy membranes are important key materials for hydrogen purification technologies.1–5 For example, Pd–Ag or Pd–Cu alloy membranes are widely used practically for the separation and purification of hydrogen gas.5 Recently, there has been a great demand for the development of new hydrogen permeable alloys to reduce the material cost as well as to improve the hydrogen permeability.6–11 Nb-based and V-based alloys are promising materials for hydrogen permeable membrane to be substituted for currently used Pd-based alloys. This is because they are less expensive and
Contributing Editor: Yang-T. Cheng a) Address all correspondence to this author. e-mail: [email protected] DOI: 10.1557/jmr.2016.416
possess higher hydrogen permeability than Pd-based alloys.7–11 However, a brittle fracture likely occurs during the operation under high pressure H2 gas atmosphere which impedes the practical use of these alloy membranes.6,12 Recently, the mechanical properties of niobium (Nb) and vanadium (V) membranes in hydrogen gas atmosphere at high temperature have been investigated by the in situ small punch (SP) test method.13,14 It is found that a ductile-to-brittle transition occurs drastically at the hydrogen concentration around 0.2–0.25 (H/M) for both Nb and V membranes.13,14 This critical hydrogen concentration is referred to as the DBTC (the Ductile-to-Brittle Transition hydrogen Concentration). To prevent a brittle fracture of the membrane with group 5 metals suc
Data Loading...
