The passivation of nickel in aqueous solutions—II. An in situ investigation of the passivation of nickel using optical and electrochemical techniques

Smith, R. Jeffrey; Hummel, Rolf E.; Ambrose, J. R.

doi:10.1016/0010-938x(87)90039-4

Cited by 45 publications

(27 citation statements)

References 31 publications

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“…7) reveal an increase in the slopes of the q ox vs. log t p plots as the temperature increases. Consequently, our data contradict what is expected on the basis of nucleation-and-growth theory and prove that this growth mechanism is not applicable to the formation of α-Ni(OH) 2 on a Ni(poly) electrode despite alternative claims being made elsewhere [15,17,32]. In conclusion, the point defect model, the electron tunneling, and the nucleation-and-growth model fail to explain the trends in the growth of α-Ni(OH) 2 on a Ni(poly) electrode that are reported above for the range of E p , t p , and T values.…”

Section: Mechanisms Of Ni Electro-oxidation In Basic Solutionscontrasting

confidence: 78%

“…This has been demonstrated by cyclic voltammetry (CV) experiments that show a well-defined anodic peak [13][14][15][16][17][18][19][20][21][22][23][24]. This process is reversible in the sense that α-Ni(OH) 2 can be electrochemically reduced to metallic Ni; the latter process gives rise to a cathodic peak in the range 0.1≤E≤−0.20 V vs. RHE.…”

Section: Introductionmentioning

confidence: 95%

“…Various reaction mechanisms were proposed for the electro-oxidation of Ni in basic aqueous electrolyte solutions and include the nucleation-and-growth model [15,17,22,32], the formation of O-containing species through electro-adsorption [32], and the dissolution and precipitation of Ni 2+ compounds [13,22,26,27,30]. Furthermore, the reported thickness of α-Ni(OH) 2 varies from one to seven monolayers (ML); thus, the existing data vary and are inconclusive [18,23,32].…”

Section: Introductionmentioning

confidence: 99%

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Electrochemical Growth of Surface Oxides on Nickel. Part 1: Formation of α-Ni(OH)2 in Relation to the Polarization Potential, Polarization Time, and Temperature

2011

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Electro-oxidation of Ni(poly) in 0.5 M aqueous KOH solution at various polarization potentials (E p ) up to 0.5 V vs. reversible hydrogen electrode, for polarization times (t p ) up to 2 h, and at 285≤T≤318 K leads to the formation of a thin layer of α-Ni(OH) 2 . Interfacial capacitance measurements show that the Ni(poly) electrode covered with a layer of α-Ni(OH) 2 can be completely reduced back to its metallic state by applying a negativegoing potential scan with a lower potential limit of −0.2 V. An increase of E p , t p , and/or T results in an increase of the thickness of the α-Ni(OH) 2 layer, which, however, never exceeds two monolayers. The electrochemical formation of α-Ni(OH) 2 follows a direct logarithmic growth kinetic law. The results reported in this contribution and their interpretation imply that other oxide growth theories, such as the Langmuir-type adsorption, the point defect model, the electron tunneling, or the nucleation-and-growth model, are not applicable to the growth of α-Ni(OH) 2 . The potentiostatic growth of α-Ni(OH) 2 on Ni(poly) is successfully treated by applying the interfacial place-exchange mechanism and the associated kinetic law.

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Section: Mechanisms Of Ni Electro-oxidation In Basic Solutionscontrasting

confidence: 78%

Section: Introductionmentioning

confidence: 95%

Section: Introductionmentioning

confidence: 99%

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Electrochemical Growth of Surface Oxides on Nickel. Part 1: Formation of α-Ni(OH)2 in Relation to the Polarization Potential, Polarization Time, and Temperature

2011

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“…According to the literature, however, prevailing product of Ni oxidation should be Ni(OH) 2 [3][4][5][6][7][8][9][10][11][12][13]86,87]. Thus, obtained small values of M a must be interpreted as an effect of the surface coverage of the electrode with the mixture of both compounds, i.e., NiO and Ni(OH) 2 , as it was also proposed in [10].…”

Section: Reagentsmentioning

confidence: 93%

“…Very often this scheme is also used for analysis of the processes taking place on metallic Ni electrodes. Although most of the authors accept that in alkaline solutions metallic Ni electrode is oxidised to Ni(OH) 2 [3][4][5][6][7][8][9][10][11][12][13] some reports suggest that also NiO could be generated during the processes at E < À500 mV vs. SCE [10,[14][15][16]. Also, the mechanism of the process is not clear: nickel oxidation could proceed according to 2D nucleation scheme [5,6], with formation of a 3D structures [12] or with participation of dissolution-redeposition mechanism [9,14,15].…”

Section: Introductionmentioning

confidence: 98%

EQCM studies on oxidation of metallic nickel electrode in basic solutions

Grdeń

Klimek

2005

Journal of Electroanalytical Chemistry

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Active Electrode Redox Reactions and Device Behavior in ECM Type Resistive Switching Memories

Lübben

Valov

2019

Adv Elect Materials

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atoms of the active metal, electrically connecting both electrodes through the solid electrolyte. [11] The formation of this filament is preceded by (partial) oxidation of the active electrode under positive bias. Because of field accelerated transport, the so-formed cations are migrating through the solid electrolyte thin film (e.g., Ta 2 O 5 , HfO 2 , or SiO 2 ) toward the counter electrode. The cations are reduced at the negatively charged counter electrode and form a nucleus facilitating further fast filament growth. Filament growth continues until short circuit conditions are reached and the driving forces for the electrochemical redox processes and ion migration are diminished. The transition from the high resistive state (HRS) into a low resistive state (LRS) is the SET process. When a negative bias is applied to the active electrode, the filament is disrupted and driven by same forces, but in opposite direction it is assumed to be completely dissolved. The device is switched from LRS to HRS that is the RESET.Since electrochemical electrode processes are spatially separated, SET event requires a counter electrode reaction at the CE to keep overall electroneutrality of the system. For most oxide-based solid electrolytes, this counter reaction involves a reduction of moisture, incorporated in the films from the ambient or during preparation steps (e.g., lithography, rinsing, atomic layer deposition (ALD) deposition, etc.). Reduction of water is kinetically favorable compared to reduction (and decomposition) of the oxide itself [12] and therefore the redox processes related to moisture can be a limiting factor for the switching kinetics. [13] Furthermore, incorporated moisture can also enhance the cation mobility. [14] In ECM devices, typically silver or copper electrodes are used. In addition, metals such as Ti [15] or alloys/compounds have been suggested as active electrodes. [16,17] The advantage of these alternative systems is considered to be the direct supply of mobile ions, avoiding the necessity of direct electrode oxidation and related energy consumption. However, in most of the cases the choice of active electrode materials is based mainly on empirical observations and the electrochemical properties of the materials toward oxidation and reduction have not been considered.In this work, we investigate the electrochemical redox behavior of several metals covering a range from noble to transition metals (Ag, Al, Au, Cu, Fe, Ni, Ta Ti, V, and Zr) as active electrode materials using Me/SiO 2 /Pt system. Cyclic voltammetry (CV) measurements are used to provide information on the redox processes occurring prior to the switching events. In addition, we performed I-V switching experiments with three different thicknesses of the solid electrolyte down to 5 nm Electrochemical metallization cells rely on oxidation, reduction, and migration of metal cations in nanoscale thin films. The cations are typically provided by the oxidation of the active electrode. Commonly, Cu, Ag, or their compounds are used as electro...

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The passivation of nickel in aqueous solutions—II. An in situ investigation of the passivation of nickel using optical and electrochemical techniques

Cited by 45 publications

References 31 publications

Electrochemical Growth of Surface Oxides on Nickel. Part 1: Formation of α-Ni(OH)2 in Relation to the Polarization Potential, Polarization Time, and Temperature

Electrochemical Growth of Surface Oxides on Nickel. Part 1: Formation of α-Ni(OH)2 in Relation to the Polarization Potential, Polarization Time, and Temperature

EQCM studies on oxidation of metallic nickel electrode in basic solutions

Active Electrode Redox Reactions and Device Behavior in ECM Type Resistive Switching Memories

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