Current-potential relationships for the half-reactions in two electroless nickel plating baths using the quartz crystal microbalance electrode

Gafin, A. H.; Orchard, S. W.

doi:10.1007/bf01023726

Cited by 24 publications

(13 citation statements)

References 14 publications

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“…25 A dehydrogenation step is essential for this ion to function as a powerful reductant and this is usually achieved by adding a catalyst and heating the solution to a high temperature. [26][27][28] This is consistent with the high activation energy ͑17.7 kcal mol −1 ͒ found for the Ni-P electroless deposition process due to the fact that the P-H chemical bond must be broken. 7,29 Due to the irradiation by high flux of energetic x-ray photons ͑energy Ͼ10 keV͒ of hypophosphite ions, bonds such as H-P, P-O, and P v O might undergo broken to various extents depending on the x-ray absorption by the involved elements.…”

Section: E Mechanismssupporting

confidence: 82%

Photosynthesis and structure of electroless Ni–P films by synchrotron x-ray irradiation

Hsu

Wang

Yang

et al. 2007

Journal of Vacuum Science &Amp; Technology A: Vacuum, Surfaces, and Films

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The authors describe an electroless deposition method for thin films, based on the irradiation by an x-ray beam emitted by a synchrotron source. Specifically, Ni-P films were deposited at room temperature. This synthesis is a unique combination of photochemical and electrochemical processes. The influence of the pH value on the formation and structural properties of the films was examined by various characterization tools including scanning electron microscopy, x-ray diffraction, and x-ray absorption spectroscopy. Real time monitoring of the deposition process by coherent x-ray microscopy reveals that the formation of hydrogen bubbles leads to a self-catalysis effect without a preexisting catalyst. The mechanisms underlying the deposition process are discussed in details.

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Section: E Mechanismssupporting

confidence: 82%

Photosynthesis and structure of electroless Ni–P films by synchrotron x-ray irradiation

Hsu

Wang

Yang

et al. 2007

Journal of Vacuum Science &Amp; Technology A: Vacuum, Surfaces, and Films

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“…[23][24][25][26][27] The adsorption/dehydrogenation reactions would be catalyzed by the presence of nickel species. Electroless deposition accompanies hydrogen radical evolution and it can reduce other reactants such as Ni 2+ , H 3 PO 2 , and itself 28…”

Section: Resultsmentioning

confidence: 99%

Ab Initio MO Study on the Reaction Mechanism of Reduction of Hypophosphorous Acid

Cui

Zhao

et al. 2005

J. Electrochem. Soc.

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The reduction mechanism of hypophosphorous acid has been investigated by ab initio calculations at the MP2/6-311G͑d,p͒ and CBS-QB3 levels. Two mechanisms with three possible pathways have been proposed for the process. The first mechanism that can be viewed as a direct mechanism contains two possible pathways, giving H 3 PO 2 + H → P + 2H 2 O. The other, as an indirect mechanism, is H 3 PO 2 + 2H → PH 3 + 2OH − . Theoretical calculations predict four transition states with the highest barrier height of 37.7 kcal/mol in the indirect mechanism, which is the most likely pathway compared to others.To form the nickel phosphorus alloy film by electroless plating or electroplating, hypophosphite can be used as a reactant to supply the phosphorus atom. 1 The performance of the alloy film is, usually, predominated by the content of phosphorus in the coatings. [2][3][4][5] In order to control the content, it is necessary to know the details of the reduction process of hypophosphorous acid, although it is not fairly understood.The mechanism of the reduction of hypophosphorous acid has been a subject of intense debate in electrochemistry. At least two mechanisms have been proposed. One of them, referred to as a direct mechanism, considered the direct reduction of hypophosphite to phosphorus element. On the contrary, the other follows an indirect mechanism via phosphine formation, which transfers to phosphorous element. 6-10 Both cases contain the bond breakage and formation of phosphorus species.Many researches have been reported on the reactions that H and OH species react with phosphorous oxides and acids, theoretically. Homma and his co-workers 11,12 applied ab initio molecular orbital method to study oxidation of hypophosphite ion via different intermediates at the level of MP2/6-311G͑d,p͒. Mackie et al. 13,14 and Twarowski 15,16 have reported the results of quantum chemistry calculations on the recombination of H and OH catalyzed by the phosphorous oxides and acids, such as PO 2 , HOPO, and HOPO 2 . They thought phosphorous oxides and acids should be capable of undergoing reactions of addition with OH or H and subsequent decomposition of recombination products. 14 In this study, we performed theoretical investigations on the reduction of hypophosphorous acid from three possible pathways. Our purpose is to clarify the indirect mechanism in this process. To our knowledge, no experimental data regarding the details of the reaction mechanism and the possible intermediates are available so far. We attempt to give insight into the mechanism details by increasing our calculation accuracy. This work may, then, pave the way for further considering the real surroundings, including the solvent effect, electrode effect, and electric field effect. Computational MethodsTheoretical calculations were carried out with a Gaussian 03 program package. 17 The geometries of the reactants, products, intermediates, and transition states were optimized at the MP2/6-311͑d,p͒ level. Harmonic vibrational frequency calculations for zero-point ener...

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“…So, in the absence of catalytic surfaces the hypophosphite species are quite stable in aqueous solutions while they can be oxidized in the presence of certain metals such as nickel (Ohno et al, 1985). According to the literature, the first step should be a non-Faradic step, followed by its reorientation and the hemolytic breakdown of P-H bond (Ohno, 1991;Gafin and Orchard, 1992;Abrantes and Correia, 1994;Marshall, 1983). In addition, an electron exchange between P and H atoms and the adsorption/dehydrogenation should be catalyzed by the presence of nickel species (Ohno, 1991;Abrantes and Correia, 1994).…”

Section: Effect Of Niso 4 Concentration On Deposition Ratementioning

confidence: 99%

“…Generally the autocatalytic depositions usually result from two reactions: anodic oxidation of the reducing agent (sodium hypophosphite) and the cathodic discharge of the metallic ions (Wiese and Weil, 1987;Gafin and Orchard, 1992). Cyclic voltammetry was carried out to characterize these equations processes.…”

Section: Electrochemical Studymentioning

confidence: 99%

Preparation and characterization of electroless Cu–P deposition protection for mild steel corrosion in molar hydrochloric solution

Belakhmima

Errahmany

Touhami

et al. 2017

Journal of the Association of Arab Universities for Basic and A

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A new basic formulation of electroless Cu-P plating using sodium hypophosphite as reducing agent was developed at different concentration of NiSO 4 . So, the effect of temperature solution, pH and immersion time on deposition rate was also investigated. It is found that the deposition rate increases with nickel sulphate concentration and temperature and decreases with immersion time. The cyclic voltammetry study showed that the electroless deposition was controlled by the anodic processes. In addition, the scanning electron microscopy (SEM) observations and energy dispersive X-ray (EDX) analysis were used to characterize Cu-P deposit. Thus, the micrograph showed that coating presents a nodular aspect and is relatively homogeneous. Finally, the corrosion protection of mild steel by this coating in 1.0 M HCl was studied using electrochemical measurements. It is found that the protection increases with NiSO 4 concentration and reaches 92% at 2 g L À1 .

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Current-potential relationships for the half-reactions in two electroless nickel plating baths using the quartz crystal microbalance electrode

Cited by 24 publications

References 14 publications

Photosynthesis and structure of electroless Ni–P films by synchrotron x-ray irradiation

Photosynthesis and structure of electroless Ni–P films by synchrotron x-ray irradiation

Ab Initio MO Study on the Reaction Mechanism of Reduction of Hypophosphorous Acid

Preparation and characterization of electroless Cu–P deposition protection for mild steel corrosion in molar hydrochloric solution

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