Deposition of Zn–Co by constant and pulsed current
01 Jan 1998-Journal of Applied Electrochemistry (Kluwer Academic Publishers)-Vol. 28, Iss: 1, pp 89-95
TL;DR: In this article, the initial stages of both Zn-Co and Zn electrodeposition were investigated by electrochemical quartz crystal microgravimetry (EQCM), and the initial electrode mass growth, determined under both pulse and constant current conditions, was much higher than predicted by Faraday's law.
Abstract: The initial stages of both Zn–Co and Zn electrodeposition were investigated by electrochemical quartz crystal microgravimetry (EQCM). The initial electrode mass growth, determined under both pulse and constant current conditions, was much higher than predicted by Faraday's law. This was explained in terms of the precipitation of scarcely soluble compounds of zinc on an electrode surface. The EQCM data confirm that the hydroxide suppression mechanism explains the anomalous Zn and Co codeposition. A nonuniform adsorption of brightener (benzalaceton) on the profiled surface was concluded on the basis of plating distribution investigations. The additive adsorbs to a greater extent on the surface projections.
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TL;DR: A review on pulse and pulse reverse techniques for electrodeposition has been attempted as mentioned in this paper, where the effects of mass, transport, electrical double layer pulse parameters and current distribution on surface roughness and morphology are presented.
731 citations
TL;DR: In this article, an AFM, XRD, XPS and XPS analyses were performed to characterize Zn, Zn-Co and Zn−Ni electrodeposit topography, texture, lattice imperfections, as well as superficial corrosion product film composition and properties.
92 citations
TL;DR: In this article, the influence of cobalt on the electrodeposition of zinc onto AISI 1018 steel was studied in weakly alkaline glycine solutions, and experimental studies of electrochemical behavior and deposit properties were conducted.
68 citations
TL;DR: In this article, a heat treatment effect on the microstructure and corrosion properties of electrodeposited Zn, Zn-Co and ZnNi alloy coatings was studied.
Abstract: A heat treatment effect on the microstructure and corrosion properties of electrodeposited Zn, Zn-Co, Zn-Fe and Zn-Ni alloy coatings was studied. Surface morphology examinations were carried with AFM, while XRD was used to determine metal lattice parameters, texture and phase composition. Low-temperature annealing (at 225 °C) caused the formation of intermetallic Fe/Zn compounds, a transformation of amorphous oxide inclusions to the crystalline form and a decrease in the Zn lattice parameter for Zn-Co and Zn-Fe alloys. The mentioned structural modifications were not accompanied, however, by corrosion behavior changes of these coatings. On the Zn-Ni alloy, the annealing caused a significant reduction in the diffraction peak width and simultaneous considerable augmentation of the corrosion current. This effect is related to the formation of a less disordered lattice for this alloy.
68 citations
TL;DR: In this paper, the electroplating of ternary Zn-Ni-Co alloy, surface morphology and corrosion resistance were investigated and contrasted with the characteristics of Zn−Ni electrodeposits.
Abstract: The electroplating of ternary Zn–Ni–Co alloy, surface morphology and corrosion resistance were investigated and contrasted with the characteristics of Zn–Ni electrodeposits. The investigation of electrodeposition was carried out using cyclic voltammetry and galvanostatic techniques, while potentiodynamic polarization resistance and anodic linear sweeping voltammetry techniques were used for corrosion study. Under the examined conditions, the electrodeposition of the alloy was of anomalous type. It was found that the obtained Zn–Ni–Co alloy exhibited more preferred surface appearance and better corrosion resistance compared to Zn–Ni alloy that electrodeposited at similar conditions. During the cathodic scan of cyclic voltammetry, a cathodic peak at − 574 mV is appeared and correlated with the deposition of sulfur liberated from the reduction of sulphate group in the presence of H + . Up to four anodic peaks were obtained by cyclic voltammetry technique, two correlated with zinc oxidation from pure deposited Zn and γ-Ni 5 Zn 21 phases and two correlated with oxidation of cobalt and nickel, were observed. The phase structure, surface morphology and chemical composition of the deposits were characterized by means of X-ray diffraction analysis, scanning electron microscopy and atomic absorption spectroscopy, respectively.
63 citations
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TL;DR: In this paper, eigenfrequenz der Platte infolge Vergroserung der schwingenden Masse is vermessen, so das eine empirische Eichung bei der Schichtwagung mit Schwingquarzen entfallt.
Abstract: Wird eine Fremdschicht auf eine zu Dickenscherungsschwingungen angeregte Schwingquarzplatte aufgebracht, so andert sich die Eigenfrequenz der Platte infolge Vergroserung der schwingenden Masse. Da die Frequenzanderung eines Schwingquarzes sehr genau vermessen werden kann, ergibt sich daraus eine sehr empfindliche Methode zur Wagung dunner Schichten. Massenbelegung der Fremdschicht und Frequenzanderung sind einander proportional. Die Proportionalitatskonstante last sich aus der Eigenfrequenz des Schwingquarzes berechnen, so das eine empirische Eichung bei der Schichtwagung mit Schwingquarzen entfallt. Die Genauigkeit des Schichtwageverfahrens ist in erster Linie durch die Temperaturabhangigkeit der Quarzeigenfrequenz begrenzt und betragt bei 1° C zugelassener Temperaturschwankung etwa ±4 · 10−9 g · cm−2. Das entspricht einer mittleren Dicke von 0,4 A bei der Dichte ϱ=1 g · cm−3. Das Verfahren wurde auch zur direkten Wagung einer Masse ausgenutzt (Mikrowagung). Dabei lies sich eine Genauigkeit von 10−10g erreichen.
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