Ta-W Alloy for Hydrogen Permeable Membranes

Abstract

The alloying effects of tungsten on the hydrogen solubility, the resistance to hydrogen embrittlement and the hydrogen permeability are investigated for Ta-based hydrogen permeable membranes. The hydrogen solubility is found to decrease by the addition of tungsten into tantalum or by increasing the temperature. It is also found that the mechanical properties (i.e., strength and ductility) for Ta-based alloy is better than that for Nb-based alloy in hydrogen atmosphere at high temperature. It is demonstrated that the Ta-5 mol%W alloy possesses excellent hydrogen permeability without showing any hydrogen embrittlement when used under appropriate permeation conditions. For example, the hydrogen flux for Ta-5 mol%W alloy measured at 773 K under the pressure condition of inlet/outlet = 0.15/0.01 MPa is about 5 times higher than that for Pd-27 mol%Ag alloy measured at the same testing condition.

A Review for Consistent Analysis of Hydrogen Permeability through Dense Metallic Membranes

“…Although Pd-based alloy membranes are promising materials for hydrogen separation and purification, non-Pd-based alloy membranes are strongly required in order to reduce material costs and improve hydrogen permeability. Group 5 metal (Nb, V, and Ta)-based alloy membranes have been recently developed [39][40][41][42] because they are less expensive and exhibit higher hydrogen permeability than Pd [43]. However, Group 5 metals exhibit poor resistance to hydrogen embrittlement, which is a large barrier to the practical use of them.…”

Hydrogen Permeability Through Tantalum Alloys Allowed With Nb and W

“…Проведен сравнительный анализ характеристик растворимости, проницаемости и водородной охрупчиваемости, изложенных в работах [8,11,13]. Так, для гидрированного бинарного сплава…”

“…В работе [8] исследованы механические характеристики металлов V группы и их сплавов методом скачкообразной подачей давления водорода на входную сторону мембраны при высокой температуре. В целях предотвращения охрупчивания, концентрация водорода должна быть T -температура), -область пороговых температурных состояний -с интерметаллидными переходами и развитием хрупкости [12][13]. Для устойчивости процессов газового разделения и производительности по выходу водорода рекомендуется [8], во-первых, наращивать разницу концентраций водорода на входе и выходе, а во вторых -ускорить процессы сорбции/десорбции водорода и его поглощаемость и, в третьих, -контролировать уровень концентрации и наклон рассчитываемой кривой дифференциальной зависимости…”

Hydrogen and Deuterium Solubility, Diffusivity and Permeability from Sorption Measurements in the Ni33Ti39Nb28 Alloy

“…Although Pd–Ag reactors are an industrial reality, in the past years, there have been many attempts to find different materials with similar permeation properties but comprising less noble, less critical and less expensive metals [ 1 , 2 , 3 ]. Many materials have been proposed, mainly derived from V [ 7 ], Ta [ 8 ] and Nb [ 9 ], which, as single elements, exhibit permeation properties higher than those of pure Pd [ 10 ]. Due to the high solubility of hydrogen in the pure metals and the consequent embrittlement, all metals were used in alloyed forms to improve their mechanical stability.…”