TY - JOUR
T1 - Electrodeposition behavior of a Zn-Ni alloy in an alkaline zincate solution
AU - Nakano, Hiroaki
AU - Arakawa, Shingo
AU - Takada, Yuya
AU - Oue, Satoshi
AU - Kobayashi, Shigeo
N1 - Copyright:
Copyright 2012 Elsevier B.V., All rights reserved.
PY - 2012
Y1 - 2012
N2 - Electrodeposition behavior of Zn-Ni alloys was investigated at current densities of 10-500 A·m -2 and a charge of 5 × 10 4C·m -2 in an unagitated zincate solution containing triethanolamine, which forms a stable complex with Ni 2+ ions at 308K. At low current densities, the Zn-Ni alloy exhibited normal codeposition, wherein electrochemically more noble Ni deposited preferentially, while at high current densities, it exhibited anomalous codeposition, wherein less noble Zn deposited preferentially. Ni deposition and H 2 evolution were significantly suppressed in the region of anomalous codeposition at higher current densities, showing the formation of an inhibitor for deposition, which results from Zn 2+ ions in the cathode layer. In contrast, in the region of normal codeposition at lower current densities, the underpotential deposition of Zn apparently occurred with Ni. Because Zn-Ni alloys are composed of a stable intermetallic compound of Ni 5Zn 21, the activity coefficient of Zn in the deposit appears to decrease remarkably.
AB - Electrodeposition behavior of Zn-Ni alloys was investigated at current densities of 10-500 A·m -2 and a charge of 5 × 10 4C·m -2 in an unagitated zincate solution containing triethanolamine, which forms a stable complex with Ni 2+ ions at 308K. At low current densities, the Zn-Ni alloy exhibited normal codeposition, wherein electrochemically more noble Ni deposited preferentially, while at high current densities, it exhibited anomalous codeposition, wherein less noble Zn deposited preferentially. Ni deposition and H 2 evolution were significantly suppressed in the region of anomalous codeposition at higher current densities, showing the formation of an inhibitor for deposition, which results from Zn 2+ ions in the cathode layer. In contrast, in the region of normal codeposition at lower current densities, the underpotential deposition of Zn apparently occurred with Ni. Because Zn-Ni alloys are composed of a stable intermetallic compound of Ni 5Zn 21, the activity coefficient of Zn in the deposit appears to decrease remarkably.
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U2 - 10.2320/matertrans.M2012241
DO - 10.2320/matertrans.M2012241
M3 - Article
AN - SCOPUS:84868149885
VL - 53
SP - 1946
EP - 1951
JO - Materials Transactions
JF - Materials Transactions
SN - 0916-1821
IS - 11
ER -