Characterization of the surface film growth during the electrochemical process: Part 2 (90 % copper-10 % nickel system)
In order to understand the resistance of passive films formed during corrosion processes, an analytical technique using x-ray diffraction was developed to examine the structure of metal in closest proximity to the metal/liquid interface. The in-situ structure at the metal liquid interface was examined for 90 % copper and 10 % nickel (90-10 Cu-Ni) in KOH solution at room temperature and at four different potentistatically controlled potentials ({minus}0.5 V, {minus}0.1 V, +0.5 V and +0.10 V versus Ni/NiO). The chemical changes at the metal interface were studied over a period of 48 hours. It was found that the integrity of the 90-10 Cu-Ni foil in KOH was lost after a continued application of the potential over 48 hours. The x-ray diffraction results indicated that the structure of both the inner and the outer passive layers, at {minus}0.5V and {minus}0.1 V (versus Ni/NiO), is comprised of Ni(OH){sub 2}, Cu(OH){sub 2}, NiOOH and Cu{sub 2}O NiO. Similarly the structure of the interfaces at +0.5 V and +0.10 V (versus Ni/NiO) contains NiO, Ni{sub 2}O{sub 3}, Cu{sub 2}O NiO and Ni{sub 2}CuO{sub 3}. XPS analysis of the surface structure (primarily of the outer passive layer) suggests that at {minus}0.50 V (versus Ni/NiO) the structure consists of Ni(OH){sub 2}, Cu(OH){sub 2} and CuO. The structure at +0.50 V (versus Ni/NiO) consists of NiO, Ni{sub 2}O{sub 3}, Ni(OH){sub 2}, Cu(OH){sub 2} and CuO. It is therefore possible that the structure of inner passive layer may be NiOOH at {minus}0.5 V and {minus}0.10 V and Ni(OH){sub 2} at +0.50 V and +0.1 V.
- Research Organization:
- Naval Surface Warfare Center, Carderock Div., Bethesda, MD (United States)
- OSTI ID:
- 350697
- Report Number(s):
- AD-A--360533/XAB; CARDIVNSWC-TR--61-98-21
- Country of Publication:
- United States
- Language:
- English
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