Analysis of the initial stages of electrocrystallization of Fe, Co and Fe-Co alloys in chloride solutions

Abstract

A eletrodeposição de Fe, Co e ligas de Fe-Co foi investigada a partir de soluções de cloreto em pH 2.0. As ligas Fe-Co foram depositadas a partir de soluções com razão molar de 1:10, 1:1 e 10:1. O processo de eletrocristalização dos metais foi estudado através de saltos potenciostáticos. O modelo de Scharifker e Hills foi utilizado para analisar os transientes de corrente. Os resultados experimentais obtidos para Co e ligas de Fe-Co, depositadas a partir da solução de 1:10 ajustaramse ao de um mecanismo de nucleação progressiva. No caso de Fe puro e ligas de Fe-Co, depositadas a partir das soluções 1:1 e 10:1, o processo de nucleação ocorreu pelo mecanismo de nucleação instantânea. A densidade do número de núcleos calculados variou de 2.6 a 19.1 x 10 3 cm-2 para Fe e a taxa de formação de núcleos para Co de 0.10 a 15.8 x 10 6 cm-2 s-1. The electrodeposition of Fe, Co and Fe-Co alloys onto Pt has been investigated from chloride solutions at pH 2.0. The Fe-Co alloys were deposited from solutions with molar ratio of 1:10, 1:1 and 10:1. Electrocrystallization of metals was studied by potentiostatic steps. The Scharifker and Hills model was used to analyze current transients. A progressive nucleation mechanism was found to fit the experimental results for both Co and Fe-Co alloys deposited from 1:10 solution. In the case of pure Fe and Fe-Co alloy, deposited from 1:1 and 10:1 solutions, the nucleation process occurred by the instantaneous mechanism. The nuclei number densities and rate of nucleation were calculated and their values were 2.6 to 19.1 x 10 3 cm-2 for Fe and 0.10 to 15.8 x 10 6 cm-2 s-1 for Co deposition.

Preparation and characterization of electrodeposited iron + cobalt thin films from a chloride bath

“…Bento and Mascaro 16 verified that the iron deposition occurs at more negative potentials than cobalt deposition because cobalt is a nobler metal and established that FeCo alloys in 1:1 and 10:1 ratios exhibited an instantaneous nucleation mechanism.…”

“…13 Literature on the electrodeposition of alloys of the iron group metals (Ni, Fe, Co and Zn), is rather extensive, comprising several papers. [14][15][16][17][18] These alloys have many useful properties such as high internal strength, hardness, high corrosion resistance and unusual magnetic properties. Many magnetic alloys with different compositions are widely employed for various purposes.…”

“…Ferromagnetic alloys, e.g., Fe-Co and Fe-Ni have received considerable attention for their practical applicability in modern industries, such as rocketry, computers, space technology, etc. 6,[14][15][16][18][19][20][21][22][23] Myung and Nobe 18 detected that the corrosion resistance of Fe-Co alloys were an order of magnitude lower than Fe-Ni and Co-Ni. On the other hand, the same authors determined the substantial increase in corrosion resistance by addition of Ni to Fe-Co deposits and the slight effect on this parameter with addition of B. Lallemand et al 20 observed that the codeposition of cobalt and iron leads to a reduction of the reaction rate of the more noble component and an increase of the reaction rate of the less noble component even if organic additives are adsorbed on the electrode surface, and affecting the polarization curves of single metals.…”

“…Ferromagnetic alloys, e.g., Fe-Co and Fe-Ni have received considerable attention for their practical applicability in modern industries, such as rocketry, computers, space technology, etc. 6,[14][15][16][18][19][20][21][22][23] Myung and Nobe 18 detected that the corrosion resistance of Fe-Co 91 Preparation and Characterization of Electrodeposited Iron + Cobalt Vol. 17, No.…”

Kinetical study about the cobalt electrodeposition onto polycrystalline platinum

“…[1][2][3][4][5][6][7] Most CoL have been prepared employing molecular beam sputtering, 8 evaporation techniques, 9,10 and more recently, electrodeposition. [11][12][13][14][15][16][17][18][19][20][21] Although it is well known that electrodeposition contributes to achieving reliable and inexpensive methods to produce CoL on metallic substrates, [22][23][24][25] to the best of our knowledge, few studies have considered Co electrodeposition on Pt electrodes. [11][12][13][14][15][16][17][18][19][20][21] Most of these studies have been conducted from sulfate and chloride ammoniacal solutions.…”