Multicomponent alloy V-15(Fe–Co–Cr–Ni) for hydrogen filters: Solubility and structure

Abstract

Vanadium is a promising base for the manufacture of highly permeable hydrogen diffusion filters. In this study, the multi-component alloy V-15 (Cr–Co–Fe–Ni) was investigated and compared with the previously investigated alloy V–15Ni. The V-15 (Cr–Co–Fe–Ni) alloy showed acceptable hydrogen solubility comparable to that of the V–15Ni alloy. Hydrogen solubility parameters were determined in the temperature range 100–600 °C and pressure 0.1–1000 Torr.

The microstructure of the alloy has a dendritic type. The vanadium content varies from 74 to 90 at.%. Nickel forms the largest microsegregations. The most uniformly distributed element is chromium, which dissolves indefinitely in vanadium.

Microcracks were detected in the sample after 92 cycles of hydrogen saturation. They mainly passed through areas of higher vanadium concentration and therefore with the highest equilibrium solubility of hydrogen. We believe that the cause of the cracks is local variations in the concentration of dissolved hydrogen resulting in mechanical stress.