Electrodeposition Behavior of Zn-Co Alloy from Alkaline Zincate Solution Containing Triethanolamine

被引：4

作者：

Nakano, Hiroaki ^{[1
]}

Shibata, Shitoku ^{[2
]}

Arakawa, Shingo ^{[2
]}

Oue, Satoshi ^{[1
]}

Kobayashi, Shigeo ^{[3
]}

机构：

[1] Kyushu Univ, Fac Engn, Nishi Ku, Fukuoka 8190395, Japan

[2] Kyushu Univ, Fac Engn, Fukuoka 8190395, Japan

[3] Kyushu Sangyo Univ, Fac Engn, Fukuoka, Japan

来源：

TETSU TO HAGANE-JOURNAL OF THE IRON AND STEEL INSTITUTE OF JAPAN | 2013年 / 99卷 / 05期

关键词：

zincate; zinc-cobalt alloys; electrodeposition; underpotential deposition; anomalous codeposition; nomal codeposition; NI ALLOY; SULFATE;

D O I：

10.2355/tetsutohagane.99.346

中图分类号：

TF [冶金工业];

学科分类号：

0806 ;

摘要：

Electrodeposition behavior of Zn-Co alloys was investigated at current densities of 2-500 A.m(-2) and a charge of 5 x 10(4) C.m(-2) in an unagitated zincate solution containing triethanolamine, which forms a stable complex with Co2+ ions at 308 K. At low current densities below 5 A.m(-2), the Zn-Co alloy exhibited normal codeposition, wherein electrochemically more noble Co deposited preferentially, while at high current densities above 6 A.m(-2), it exhibited anomalous codeposition, wherein less noble Zn deposited preferentially. The current efficiency for Zn-Co alloy deposition was low to be about 20% in the region of nomal codeposition at low current densities, while it was 95% in the region of anomalous codeposition at high current densities. In the region of anomalous codeposition at high current densities, the partial polarization curves for Co deposition and H-2 evolution were significantly shifted to less noble direction by coexisting of Zn2+ ions, showing the formation of an inhibitor for deposition, which results from Zn2+ ions in the cathode layer. In contrast, in the region of normal codeposition at low current densities below 5 A.m(-2), the underpotential deposition of Zn apparently occurred with Co. Because Zn-Co alloys are composed of the stable intermetallic compounds of CoZn13 and Co5Zn21, the activity coefficient of Zn in the deposit appears to decrease remarkably.

引用

页码：346 / 351

页数：6