Electrodeposition Mechanism and Process of a Novel Cyanide-Free Gold Sulfite Bath

Authors

Jia-Qiang Yang, College of Chemistry and Chemical Engineering, State Key Laboratory of Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen, 361005, China;
Lei Jin, College of Chemistry and Chemical Engineering, State Key Laboratory of Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen, 361005, China;
Wei-Qing Li, College of Chemistry and Chemical Engineering, State Key Laboratory of Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen, 361005, China;
Zhao-Yun Wang, College of Chemistry and Chemical Engineering, State Key Laboratory of Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen, 361005, China;
Fang-Zu Yang, College of Chemistry and Chemical Engineering, State Key Laboratory of Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen, 361005, China;Follow
Dong-Ping Zhan, College of Chemistry and Chemical Engineering, State Key Laboratory of Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen, 361005, China;Follow
Zhong-Qun Tian, College of Chemistry and Chemical Engineering, State Key Laboratory of Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen, 361005, China;

Corresponding Author

Fang-Zu Yang(fzyang@xmu.edu.cn);
Dong-Ping Zhan(dpzhan@xmu.edu.cn)

Abstract

A novel cyanide-free gold sulfite process is introduced in this paper. In the bath, chloauric acid was directly employed as the main salt, and hydroxyethylidene diphosphonic acid (HEDP) was used as the stabilizer and coating grain refiner. The bath stability, the gold coating morphology and the mechanism of gold electrodeposition were studied in detail. The results showed that HEDP could significantly improve the bath stability. Moreover, the grains of the gold coating obtained from the gold sulfite bath without HEDP was rod-like, which grew gradually with the increasing of the deposition time, resulting in that the appearance of the coating turned from a golden yellow to a hazy reddish brown by the increase of the coating thickness. As HEDP was introduced into the gold sulfite bath, the gold grains were transformed to pyramidal, and the grain growth rate accompanying the increase of the coating thickness was much slower than that in the gold sulfite bath without HEDP, observing the golden bright appearance within 1 μm thickness. Electrochemical curves indicated that gold electrodeposition did not undergo a nucleation stage.

Graphical Abstract

Keywords

cyanide-free gold plating, gold sulfite, hydroxyethylidene diphosphonic acid, electrodeposition, gold coating

DOI Link

https://doi.org/10.13208/j.electrochem.2213005

Publication Date

2022-07-28

Online Available Date

2022-03-17

Revised Date

2022-03-01

Received Date

2022-01-07

Recommended Citation

Jia-Qiang Yang, Lei Jin, Wei-Qing Li, Zhao-Yun Wang, Fang-Zu Yang, Dong-Ping Zhan, Zhong-Qun Tian. Electrodeposition Mechanism and Process of a Novel Cyanide-Free Gold Sulfite Bath[J]. Journal of Electrochemistry, 2022 , 28(7): 2213005.
DOI: 10.13208/j.electrochem.2213005
Available at: https://jelectrochem.xmu.edu.cn/journal/vol28/iss7/6