電析Ni-P合金電極の水電解用アノードとしての in situ 耐食性評価

概要

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To develop a highly corrosion-resistant anode electrode for use in alkaline water electrolysis, we evaluated three plated electrode samples: nickel-plated (Ni, used generally for water electrolysis), Ni-P1 (9.64 wt%P content nickel), and Ni-P2 (17.50 wt%P content nickel). The Ni-P alloy was expected to show high corrosion-resistance because Ni-P alloy containing over 8 wt%P has an amorphous structure. We compared their surface structures using XRD, compared their morphologies using SEM, and investigated their growth in situ using a quartz crystal microbalance (QCM). We also characterized their electrochemistry using CV.Because its smooth surface and distinct amorphous structure protect it against corrosion by the oxide film, Ni-P2 exhibited excellent resistance. Grain boundaries on the Ni surface caused partial corrosion, although the Ni surface was covered with a great amount of oxide film. Furthermore, Ni-P1 tends to corrode easily because it is considered to be in a transition state to an amorphous structure and has few grain boundaries on its surface. All samples exhibited almost identical oxygen overvoltage.Results show that Ni-P alloy (high P content), which had a fine amorphous structure and showed high corrosion-resistance, is a suitable anode electrode material for use in alkaline water electrolysis.
2009-02-01