TY - JOUR
T1 - Co-Ni alloy electrodeposition under different conditions of pH, current and composition
AU - Vazquez-Arenas, Jorge
AU - Altamirano-Garcia, Liliana
AU - Treeratanaphitak, Tanyakarn
AU - Pritzker, Mark
AU - Luna-Sánchez, Rosa
AU - Cabrera-Sierra, Roman
N1 - Funding Information:
The authors express gratitude to the Natural Sciences and Engineering Research Council of Canada (NSERC) and to the Mexican Council of Science and Technology (CONACyT) for their financial support to carry out this work.
PY - 2012/3/30
Y1 - 2012/3/30
N2 - Linear sweep voltammetry and cathodic polarization experiments were conducted to investigate the effects of electrolyte composition and current/overpotential on Co-Ni alloy co-deposition in sulphate solutions and its anomalous behavior whereby Co is preferentially deposited over Ni. Ni deposition was shown to be inhibited in the presence of CoSO 4 in solution, whereas the rate of Co deposition was not accelerated and, in fact, completely unaffected by the presence of NiSO 4. The extent of anomalous behavior was found to be affected strongly by the CoSO 4 concentration, but was less pronounced when Co(II) reduction became mass transfer-controlled or the NiSO 4 concentration exceeded the CoSO 4 concentration by at least one order of magnitude. Analysis of the linear scans and measurement of the deposition current efficiencies indicated that the onset of reactions occurred in the following order with increasing cathodic overpotential: H + reduction, Ni(II) reduction, Co(II) reduction and H 2O reduction. Boric acid was found to have little effect on alloy composition whenever deposition occurred to any significant extent. On the other hand, the presence of boric acid was required to attain acceptably high current efficiencies over a wide range of current densities. Moreover, effective Co-Ni deposition was not possible in the absence of boric acid.
AB - Linear sweep voltammetry and cathodic polarization experiments were conducted to investigate the effects of electrolyte composition and current/overpotential on Co-Ni alloy co-deposition in sulphate solutions and its anomalous behavior whereby Co is preferentially deposited over Ni. Ni deposition was shown to be inhibited in the presence of CoSO 4 in solution, whereas the rate of Co deposition was not accelerated and, in fact, completely unaffected by the presence of NiSO 4. The extent of anomalous behavior was found to be affected strongly by the CoSO 4 concentration, but was less pronounced when Co(II) reduction became mass transfer-controlled or the NiSO 4 concentration exceeded the CoSO 4 concentration by at least one order of magnitude. Analysis of the linear scans and measurement of the deposition current efficiencies indicated that the onset of reactions occurred in the following order with increasing cathodic overpotential: H + reduction, Ni(II) reduction, Co(II) reduction and H 2O reduction. Boric acid was found to have little effect on alloy composition whenever deposition occurred to any significant extent. On the other hand, the presence of boric acid was required to attain acceptably high current efficiencies over a wide range of current densities. Moreover, effective Co-Ni deposition was not possible in the absence of boric acid.
KW - Anomalous deposition
KW - Boric acid
KW - Co-Ni alloy
KW - pH
UR - http://www.scopus.com/inward/record.url?scp=84857358732&partnerID=8YFLogxK
U2 - 10.1016/j.electacta.2012.01.050
DO - 10.1016/j.electacta.2012.01.050
M3 - Artículo
SN - 0013-4686
VL - 65
SP - 234
EP - 243
JO - Electrochimica Acta
JF - Electrochimica Acta
ER -