Crystallization and microstructure changes in rapidly solidified Nb20Ti40Ni40 hydrogen permeation alloy

Hydrogen permeability and microstructure of rapidly quenched Nb–TiNi alloys

“…The volume fraction of the (Nb, Ti) phase is determined to be 0.44 ± 0.04 and its average diameter is 0.70-0.75 m in the annealed Nb 40 Ti 30 Ni 30 alloy. We have already reported that the amorphous Nb 20 Ti 40 Ni 40 alloy crystallized into the (Nb, Ti) + TiNi two-phase microstructure by crystallization [6][7][8]. This microstructure is very similar to that of the annealed crystalline Nb 30 Ti 35 Ni 35 alloy.…”

“…˚6 73 K of the amorphous Nb 20 Ti 40 Ni 40 alloy is almost same as the corresponding crystalline alloy [6][7][8]. The crystalline Nb 20 Ti 40 Ni 40 alloy obtained by crystallization of the amorphous alloy, consisted of the TiNi and the (Nb, Ti) phases, is ductile, but its ˚ is too low in comparison to that of pure Pd [6][7][8]. We have reported that ˚ of the arc melted Nb-TiNi alloys is improved in Nb-rich alloys, which is caused by the increase of the volume fraction of the (Nb, Ti) phase showing high ˚ [9].…”

“…The present authors have prepared the amorphous alloy ribbon by the rapid quenching of the eutectic crystalline Nb 20 Ti 40 Ni 40 alloy, and hydrogen permeability at 673 K, i.e. ˚6 73 K of the amorphous Nb 20 Ti 40 Ni 40 alloy is almost same as the corresponding crystalline alloy [6][7][8]. The crystalline Nb 20 Ti 40 Ni 40 alloy obtained by crystallization of the amorphous alloy, consisted of the TiNi and the (Nb, Ti) phases, is ductile, but its ˚ is too low in comparison to that of pure Pd [6][7][8].…”

Effect of Hf/Ni ratio on microstructure and hydrogen permeation of Nb–Hf–Ni ternary alloys

“…As we all know, palladium is expensive and not suitable for large-scale industrial application as hydrogen permeation alloy for separation and purification of hydrogen gas; therefore, palladiumbased alloys are not currently preferred for hydrogen purification [1][2][3][4], but niobium-based hydrogen permeation alloys are of the optimal choice [5]. Nb-Ti-Ni and Nb-Zr-Ni alloys have already been investigated [1,5] and Nb-Hf-Ni alloys are also studied [6].…”

“…Nb-Ti-Ni and Nb-Zr-Ni alloys have already been investigated [1,5] and Nb-Hf-Ni alloys are also studied [6]. Niobium plays an important role on the hydrogen permeability of Nb-Ti-Ni, Nb-Zr-Ni and Nb-Hf-Ni alloys [4][5][6]; however, the effect of Hf/Ni ratio on the microstructure and hydrogen permeation properties of the Nb-Hf-Ni ternary alloys was not studied. In this letter, Nb-Hf-Ni ternary alloys are particularly studied to analyze the influence of Hf/Ni ratio on the microstructures and hydrogen permeabilities of these new hydrogen permeation alloys as a progress report of the results in the other paper [6].…”