Evaluation of a new Cr-free alloy as interconnect material for hydrogen production by high temperature water vapour electrolysis: Study in cathode atmosphere

For economic and ecological reasons, hydrogen is considered as a major energetic vector for the future. Hydrogen production via high temperature water vapour electrolysis (HTE) is a promising technology. A major technical difficulty related to high temperature water vapour electrolysis is the development of interconnects working efficiently for a long period. Working temperature of 800 °C enables the use of metallic materials as interconnects. High temperature corrosion behaviour and electrical conductivity of a new Cr-free Fe–Ni–Co alloy were tested in cathode atmosphere (H2/H2O) at 800 °C. The alloy exhibits a poor oxidation resistance but an excellent ASR parameter, as a result of the formation of a highly-conductive Cr-free surface spinel layer. Moreover, the role of water vapour and hydrogen was discussed and a diffusion mechanism in cathode atmosphere could be suggested.

► A new Cr-free Fe–Ni–Co alloy as interconnect material for water steam electrolysis. ► Corrosion and conductivity tests in cathode atmosphere (H2/H2O) at 800°°C. ► Poor oxidation resistance, but excellent ASR parameter. ► The role of water vapour and hydrogen is discussed. ► A diffusion mechanism is suggested.