Corresponding Author

Jian-Wei Zhao(jwzhao@zjxu.edu.cn)


As a new development direction of integrated circuit chip carrier, etched lead frame has been gradually applied in microelectronics industry in recent years. Since the preparation of the etched lead frame requires the use of multiple layers of non-alkali-resistant photoresist films with specific patterns, and the traditional cyanide silver plating is unable to meet this requirement, making that the development of weakly alkaline cyanide free silver plating process has great significance. In this paper, a weak alkaline silver plating process based on 5,5-dimethylhydantoin (DMH) cyanide-free silver plating system was studied. The electrodeposition behavior of the system and the nucleation mechanism of silver crystallization were investigated by cyclic voltammetry (CV) and chronoamperometry (CA); By changing a series of conditions, the effective working range of the process was determined, and the properties of the coating and the bath were characterized under the optimized process conditions. The results showed that the crystals of the silver plating layer were fine, and the average particle size was 16.7 ± 3.6 nm. From the XRD test results, the effective grain size was 43.6 ± 3 nm, and the (200) crystal surface was the preferred orientation crystal plane. Coating performance tests included whiteness, brightness and hardness, which were 7.2%, 117 Gs and 74 ± 4 Hv, respectively. In addition, the performance test of the bath showed that the current efficiency of the bath reached 99.2% with the temperature was 30 oC and the current density was 0.6 ASD, and the throwing power was about 83% at 30 oC. The results of the above tests and the actual etched lead frame samples have demonstrated that this process is of great value in practical application.

Graphical Abstract


cyanide-free silver plating, lead frame, nucleation mechanism, bath properties, coating properties

Publication Date


Online Available Date


Revised Date


Received Date



[1] Sun L J(孙丽君), Yan T(闫涛), Ma J F(马景富). Design of cyanide silver electroplating wastewater synthesizing treatment platform[J]. Plating & Finishing(电镀与精饰), 2018, 40(11): 32-36.

[2] Liu M X(刘明星), Ou Z W(欧忠文), Hu G H(胡国辉), Nie Y L(聂亚林), Miao J F(缪建峰). Investigation of a new cyanide-free silver electroplating process[J]. Plating & Finishing(电镀与精饰), 2017, 39(3): 13-18.

[3] Liu A M, Ren X F, Zhang J, Yuan G H, Yang P X, Zhang J Q, An M Z. A composite additive used for an excellent new cyanide-free silver plating bath[J]. New J. Chem., 2015, 39(4): 2409-2412.
doi: 10.1039/C4NJ02060J URL

[4] Wei L A(魏立安). Cleaner production technology of noncyanide silver plating[J]. Electroplating & Finishing(电镀与涂饰), 2004, 23(5): 27-29+57.

[5] Wang S C(王思醇). Safeguard of solution and influence of impurities For non-cyaniding silver electroplating[J]. Painting & Electroplating (涂装与电镀), 2009, (2): 3.

[6] Luo G(罗龚), Li D Y(黎德育), Yuan G H(袁国辉), Li N(李宁). Applications of hydantoin compounds in cyanide-free electroplating[J]. Electroplating & Finishing(电镀与涂饰), 2016, 35(5): 268-273.

[7] Xu J(徐晶), Guo Y(郭永), Hu S Q(胡双启), Zhao L(赵璐), Li J(李江), Zhao J G(赵建国). Pulse reverse electroplating of sliver in a nicotinic acid bath[J]. Materials Protection(材料保护), 2010, 43(3): 44-46+80.

[8] Chen Y L(陈永亮). New technology for cyanide-free silver plating[J]. Plating & Finishing(电镀与精饰), 2010, 32(4): 14-17.

[9] Sun Z(孙志), Cheng N(程娜), Zhao J W(赵健伟). Application of ZHL non-cyanide silver plating solution in brush plating[J]. Plating & Finishing(电镀与精饰), 2019, 41(3): 22-27.

[10] Sun Z(孙志), Cheng N(程娜), Chen F(陈峰), Zhao J W(赵健伟). Resistance to disturbance of metallic impurities during silver electroplating in ZHL-02 alkaline cyanide-free bath[J]. Electroplating & Finishing(电镀与涂饰), 2020, 39(5): 249-254.

[11] Cheng N(程娜), Sun Z(孙志), Zhao J W(赵健伟). XRD study on cyanide-free silver plating coating[J]. Plating & Finishing(电镀与精饰), 2018, 40(12): 41-46.

[12] Jiao S(焦莎), Liu Y(刘燕), Wang B H(万冰华), Wang C(王川), Yu J Z(于建政), Zhang X L(张晓玲). Effect of bath composition and cathodic current density on current efficiency of cyanide-free alkaline zinc plating and appearance of zinc coating[J]. Electroplating & Finishing(电镀与涂饰), 2015, 34(24): 1395-1399.

[13] Bi S F(毕四富), Gong C(龚超), Tu Z M(屠振密), Li N(李宁). Effect of complexing agent on chromium plating with low chromium sulfate concentration[J]. Plating & Finishing(电镀与精饰), 2011, 33(9): 1-4.

[14] Christophe J, Guilbert G, Rayee Q, Poelman M, Olivier M G, Buess-Herman C. Cyanide-free silver electrochemical deposition on copper and nickel[J]. J. Electrochem. Soc., 2018, 165(14): D676-D680.
doi: 10.1149/2.1011813jes URL

[15] Huang S S(黄帅帅), Liu C(刘诚), Jin L(金磊), Yang F Z(杨防祖), Tian Z Q(田中群), Zhou S M(周绍民). Complex coordination silver electrocrystallization mechanism on glassy carbon electrode surface[J]. J. Electrochem.(电化学), 2018, 24(4): 344-350.
doi: 10.13208/j.electrochem.180105

[16] Liu A M, Ren X F, An M Z. A composite additive used for a new cyanide-free silver plating bath (II): An insight by electrochemical measurements and quantum chemical calculation[J]. New J. Chem., 2017, 41(19): 11104-11112.
doi: 10.1039/C7NJ02638B URL

[17] Márquez K, Staikov G, Schultze J W. Silver deposition on silicon and glassy carbon. A comparative study in cyanide medium[J]. Electrochim. Acta, 2003, 48(7): 875-882.
doi: 10.1016/S0013-4686(02)00781-8 URL

[18] Alvarez A E, Salinas D R. Nucleation and growth of Zn on HOPG in the presence of gelatine as additive[J]. J. Electroanal. Chem., 2004, 566(2): 393-400.
doi: 10.1016/j.jelechem.2003.11.051 URL

[19] Wang C(王超), Chen Y L(陈亚龙), Chen M M(陈明明), Wang Y F(王一夫). Application of pressure plate type high-speed silver plating to leadframe[J]. Electroplating & Finishing(电镀与涂饰), 2016, 35(9): 475-480.

[20] Guan H L(管华良). Experience of silver electroplating on leadframe[J]. Electroplating & Finishing(电镀与涂饰), 2017, 36(13): 701-706.

[21] Liu A M, Ren X F, Wang B, Zhang J, Yang P X, Zhang J Q, An M Z. Complexing agent study via computational chemistry for environmentally friendly silver electrodeposition and the application of a silver deposit[J]. RSC Adv., 2014, 4(77): 40930-40940.
doi: 10.1039/C4RA05869K URL

[22] Zhang J(张杰), Yu P X(俞培祥), Zhou H F(周海飞), Tao L B(陶礼兵), Shen X M(沈晓明), Chen J W(陈建伟). Performance comparison of Ag coatings on switch contact between cyanide plating and non-cyanide brush plating[J]. Corrosion and Protection(腐蚀与防护), 2014, 35(11): 1131-1134

[23] Langford J I, Wilson A J C. Scherrer after sixty years: A survey and some new results in the determination of crystallite size[J]. J. Appl. Crystallogr., 1978, 11(2): 102-113.
doi: 10.1107/S0021889878012844 URL



To view the content in your browser, please download Adobe Reader or, alternately,
you may Download the file to your hard drive.

NOTE: The latest versions of Adobe Reader do not support viewing PDF files within Firefox on Mac OS and if you are using a modern (Intel) Mac, there is no official plugin for viewing PDF files within the browser window.