Three-dimensional nucleation with diffusion controlled growth

Mostany, Jorge; Mozota, J.; Scharifker, B.R.

doi:10.1016/0022-0728(84)80208-9

Cited by 154 publications

(98 citation statements)

References 17 publications

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“…(5) In addition, it is possible to calculate the Gibbs free energy of nucleation using Eq. (8): [40][41][42] (8) Here ΔG is the Gibbs free energy of nucleation (Jnucleus −1 ); k 3 = N 0 w n +c G, where w n +c is the frequency of attachment of single atoms to the critical nucleus and G is the nonequilibrium Zeldovich factor that exponentially depends on overpotential. 43 On the other hand, k 4 = -(16pg 3 M 2 f(q)/3r 2 z 2 F 2 kT), where g is the interfacial tension between the nucleus and its mother phase and f(q) is a function of the contact angle q between the nucleus and substrate.…”

Section: Analysis Of the Kinetic Parametersmentioning

confidence: 99%

Kinetical study about the cobalt electrodeposition onto polycrystalline platinum

Ríos-Reyes¹,

Mendoza-Huízar²,

Reyes-Cruz³

et al. 2013

Quím. Nova

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Recebido em 2/10/12; aceito em 25/2/13; publicado na web em 24/5/13An electrochemical study of Co electrodeposition onto polycrystalline Pt from an aqueous solution containing 10 −2 M CoCl 2 + 1 M NH 4 CI (pH = 9.3) was conducted at overpotential conditions. The current density transients showed two maxima that corresponded to two nucleation and growth processes. The entire transient behavior was adequately predicted considering the contribution to the total current of four different processes: a Langmuir-type adsorption process, a diffusion-controlled twodimensional instantaneous nucleation, and two three-dimensional nucleation and growth processes.

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Section: Analysis Of the Kinetic Parametersmentioning

confidence: 99%

Kinetical study about the cobalt electrodeposition onto polycrystalline platinum

Ríos-Reyes¹,

Mendoza-Huízar²,

Reyes-Cruz³

et al. 2013

Quím. Nova

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“…21) It is considered that in the potential range from −0.55 V to −0.75 V, In 3+ is reduced according to the reaction (25) and/or a sequential reaction of reactions (26) and (27):…”

Section: Resultsmentioning

confidence: 99%

“…(21) and (22), I max 2 · t max must be constant under the condition of constant concentration and constant diffusion coefficient. 8,25) If we know whether the nucleation process is instantaneous or progressive we can find the diffusion coefficient from the values of I max 2 · t max . The value of I max 2 · t max obtained from potentiostatic current transients in Fig.…”

Section: 24)mentioning

confidence: 99%

“…While the nucleation of Pb on vitreous carbon showed various nucleation processes with overpotential and the nucleation of Au on glassy carbon exhibited instantaneous and progressive process before and after overlapping of particles, respectively. 29) As was discussed earlier, the deposition of indium is done by successive reaction of reactions (26) and (27) as well as reaction (25). Besides In :…”

Section: )mentioning

confidence: 99%

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Nucleation Process of Indium on a Copper Electrode

Chung¹,

Lee²

2013

Journal of Electrochemical Science and Technology

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:The electrodeposition of indium onto a copper electrode from an aqueous sulfate solution containing In 3+ was studied by means of cyclic voltammetry and chronoamperometry. Reduction and oxidation of indium on copper were investigated by using cyclic voltammograms at different negative limiting potentials and at different scan rates in cumulative cycles. Cyclic voltammograms indicated that reduction and oxidation processes of indium could involve various reactions. Chronoamperometry was carried out to analyze the nucleation mechanism of indium in the early stage of indium electrodeposition. The non-dimensional plot of the current transients at different potentials showed that the shape of the plot depended on the applied potential. The nucleation of indium at potential step of −0.6~−0.8 V was close to progressive nucleation limited by diffusion. However the nondimensional plot of current transients for the indium nucleation showed different behaviors from theoretical curves at the potential step lower than −0.8 V.

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“…Este valor já foi obtido para a nucleação de Ni sobre carbono, 9 chumbo sobre carbono vítreo, 26 cobre em paládio 27 e platina sobre tungstênio. 28 Em termos da teoria atomística dentro do intervalo de potencial investigado, zero átomos no núcleo crítico quer dizer que um simples átomo adsorvido em um sítio ativo do substrato forma um cluster estável de um átomo que pode crescer irreversivelmente nesse potencial.…”

Section: Teoria Atomísticaunclassified

Estudo da eletrocristalização de Ni e Ni-P sobre ultramicroeletrodo de platina

2008

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Recebido em 6/8/07; aceito em 26/10/07; publicado na web em 27/6/08 STUDY OF ELECTROCRYSTALLIZATION OF Ni AND Ni-P ON PLATINUM ULTRAMICROELECTRODE. This work describes a comparative study of the electrocrystallization of Ni and Ni-P on Pt ultramicroelectrodes using chronoamperometric measurements. It was possible to confirm that in all cases a progressive nucleation was the predominant mechanism. Moreover, the application of the Atomistic Theory to the experimental rate of nuclei formation showed that the number of atoms in the critical nucleus was zero, except for Ni-P on Pt at low overpotentials were a value of one was observed. Furthermore, the physical characterisation of the different deposits on Pt by atomic force microscopy allowed observing the coalescence of the hemispherical nuclei of Ni and Ni-P at t max thus confirming the results obtained from the current-time analysis.Keywords: electrocrystallization; nickel-phosphorous; Pt ultramicroelectrode. INTRODUÇÃOO estudo da eletrocristalização de níquel em diferentes substratos é de grande interesse devido sua aplicação tecnológica. 1As ligas metálicas amorfas (LMA) de Ni-P e Ni-B possuem características diferenciadas, como dureza, resistência a ataques quími-cos, aderência, soldabilidade, etc., que as tornam muito adequadas para recobrimentos protetores contra a corrosão, recobrimentos com fins ornamentais, aplicações em dispositivos eletrônicos, entre outros.Nas últimas décadas, as LMA têm atraído o interesse de muitos pesquisadores, devido as suas propriedades mecânicas, 2 magnéticas, 3 elétricas 4 e, em algumas situações por sua grande resistência contra a corrosão.5 As LMA são normalmente soluções sóli-das supersaturadas contendo um metalóide como P e/ou B.As LMA, ao contrário das ligas cristalinas, caracterizam-se por apresentarem estrutura homogênea, com arranjo desordenado dos átomos que compõem a liga. Esta é a característica fundamental deste material, pois se podem estudar as LMA em uma ampla faixa de composição sem que o material sofra transição de fase.Em ligas obtidas por deposição autocatalítica ou por eletrodeposição, o metalóide age como um agente redutor do metal, além de servir como agente causador da amorfia, já que a rede de cristalização do metal é diferente da do metalóide e esta situação pode permitir a predominância de uma estrutura amorfa no depósito. Se por um lado o metalóide estabiliza a fase amorfa, em contrapartida, a presença deste altera as propriedades magnéticas, elétricas e mecânicas por doação de elétrons aos orbitais d dos metais.As propriedades químicas também são alteradas, pois a adição do metalóide pode permitir que a liga adquira um caráter químico mais inerte, uma vez que as LMA não possuem defeitos cristalinos ou interfases nas vizinhanças dos grãos, dificultando a ocorrência de ataques localizados, como acontece com as ligas convencionais cristalinas.Um aspecto fundamental na eletrodeposição é o estudo dos estágios iniciais na formação de uma nova fase, chamada de eletrocristalização. A formação dos núcleos é, ...

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Three-dimensional nucleation with diffusion controlled growth

Cited by 154 publications

References 17 publications

Kinetical study about the cobalt electrodeposition onto polycrystalline platinum

Kinetical study about the cobalt electrodeposition onto polycrystalline platinum

Nucleation Process of Indium on a Copper Electrode

Estudo da eletrocristalização de Ni e Ni-P sobre ultramicroeletrodo de platina

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