Cyanide-based baths are generally used industrially to produce silver and gold coatings via electroplating. Baths containing ([Au(CN)2]−) and ([Ag(CN)2]−) are used for the deposition of gold and silver coatings, respectively. However, due to the severe toxicity, the technical personnel involved in work are at risk. Additionally, the disposal of cyanide-containing wastes poses a significant threat to the environment as they pollute various natural resources. The coatings produced from alkaline cyanide-based baths cause embrittlement of electronic circuit patterns. Due to these reasons, many cyanide-free baths have started to replace the existing cyanide-based baths. In the cyanide-free baths, the primary cyanide complexing agent is replaced with eco-friendly alternative compounds like sulphite, thiosulphate, thiourea, DMH, EDTA, and ionic liquids (ILs). This review article provides an overview of the various cyanide-free electroplating baths available for electroplating silver and gold that are either used for commercial practice or are developed for laboratory-scale use.
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References
1.
ElkingtonG, ElkingtonH. Improvements in coating, covering, or plating certain metals. British patent. 1840.
2.
LangbeinG, BranntW.Electroplating of metal. Philadelphia (PA): Henry Carey Baird; 1902.
3.
SmithPT. Gold plating bath and process. United States patent US 3666640A. 1962.
4.
FritzV. Electrolytic deposition of gold and gold alloys. United States patent US 2812299A. 1957.
5.
RinkerEC, RobertD. Electroplating bright gold. Google patents. 1959.
6.
KohlPA. Electrolytic plating. Google patents. 1982.
7.
NobelFI, BraschW. Silver plating. Google patents. 1981.
8.
Seegmiller R, GoreJK.A Cyanide Bath. Proceedings of the Annual Convention. 1960;47:74.
9.
SchlesingerM., PaunovicM.Modern electroplating. 5th EditionWiley; 2010. p. 131–138.
SánchezH, ChainetE, NguyenB, et al.J Electrochem Soc. 1996;143(9):2799–2804.
52.
DiBariG.Metal finishing 61st guidebook and directory issue. New York (NY): Elsevier Science; 1993.
53.
GrebeKR, PowersJV. Non-cyanide silver plating bath. United States patent US 3406107A. 1968.
54.
CuljkovicJ. Cyanide free bath for electrodeposition of silver. United States patent US 3984292A. 1976.
55.
LeahyEP, KarustisGA. Non-cyanide acidic silver electroplating bath and additive therefore. United States patent US 4067784A. 1978.
56.
HradilE, HradilH, WeisbergAM. Non-cyanide bright silver electroplating bath therefor, silver compounds and method of making silver compounds. United States patent US 4246077A. 1981.
57.
NovevTV, OvcharovSD, YordanovNS, et al. Combined brightener in sulfamate silver electroplating baths. United States patent US 4279708A. 1981.
58.
TsujiK, NishikawaT, TakeuchiT, et al. Silver and silver alloy plating bath. United States patent US 7628903B1. 2009.
59.
YauYH, RichardsonTB, AbysJA, et al. Silver plating in electronics manufacture. China patent CN101031367B. 2013.
60.
YoshimotoM, KitamuraS, OmoriS, et al. Method for silver plating. United States patent US 20070284258A1. 2007.
61.
JinJ. Non-cyanide silver plating solution and method for forming plating using it. South Korea patent.
62.
AsakawaT. Non-cyanide silver plating bath and its silver plating method. Japan patent JP3224454B2. 1993.
63.
KazutomoG. Non-cyanide silver plating method and non-cyanide solution used therefor. Patent JP3299370B2; 1993.
64.
TanakaS, YoshimotoM. Tin-silver alloy plating bath of non-cyanide system. Japan patent JP2006265572A. 2005.
65.
TakeuchiT, ObataK, MasakiS, et al. Non-cyanide displacement silver plating bath. Japan patent JPH10130855A. 1996.
JianghuaH, ChunlinZ, MinY, et al. Method for improving bonding force of non-cyanide silver plating layer on nickel layer. China patent CN102181892B. 2011.
73.
HengboY, ChaoqunG, YonghaiF, et al. Non-cyanide silver coating stable electrical plating solution, preparation method and silver-plated method thereof. China patent CN102560571B. 2012.
74.
ZhongxiaoS, LiuchengH, QinL, et al. A kind of electroplate liquid of non-cyanide silver electroplating and electro-plating method. China patent CN103046091B. 2013.
75.
QingdongZ, TongM, ShuaishuaiG, et al. Method for non-cyanide silver plating. China patent. 2013.
76.
QingdongZ, TongM, XiawenL, et al. A kind of alkaline non-cyanide is electroplated the method for Ag-Ni alloy. China patent CN103540978B. 2013.
77.
JingZ, XiuchunW, XibinY, et al. A kind of method of pulse non-cyanide silver electroplating. China patent CN103668358B. 2013.
78.
MaozhongA, AnminL, XuefengR, et al. Non-cyanide bright electroplated silver composite additive and application method thereof in non-cyanide silver electroplating system. China patent CN104018193A. 2014.
79.
GuohuiH, JunL, HaishengB, et al. High-performance cyanide-free silver pre-plating liquid. China patent CN104152952A. 2014.
80.
RongguoX. Cyanide-free silver plating solution and electroplating method. China patent CN104746113A. 2015.
81.
GuohuiH, ZhongwenO, JieM, et al. Novel cyanide-free silver plating electroplating liquid and electroplating technology. China patent CN105088293A. 2015.
82.
ChangchunT. A kind of alkaline non-cyanide plate silver plating solution and silver-coating method. China patent CN107313084B. 2017.
83.
GarichH, TaylorEJ, LiuD, et al.50th International Conference on Environmental Systems. 2021.
84.
TaylorEJ, GarichHM, InmanME. Electrochemical mirror system and method. United States patent US 10684522B2. 2020.
ValiūnienėA, BaltrūnasG, ValiūnasR, et al.J Hazard Mater. 2010;180(1-3):259–263.
91.
LukinskasP, SavickajaI, ŠukienĖV, et al.J Coord Chem. 2008;61(16):2528–2535.
92.
SatpathyB, KayalN, JenaS, et al.Mater Charact. 2022;189:112011.
93.
AzzaroniO, SchilardiPL, SalvarezzaRC, et al.Langmuir. 1999;15(4):1508–1514.
94.
AsakawaT. Silver plating baths and silver plating method using the same. United States patent US 5601696A. 1997.
95.
ClaussM, Zhang-BeglingerW. Cyanide-free silver electroplating solutions. United States patent US 8608932B2. 2013.
96.
MorrisseyR. Non-cyanide silver plating bath composition. United States patent US 20070151863A1. 2007.
97.
PizzettiF, SalviettiE, GiurlaniW, et al.J Electroanal Chem. 2022;911:116196.
98.
LiuA, RenX, ZhangJ, et al.RSC Adv. 2016;6(9):7348–7355.
99.
LiuA, RenX, YangQ, et al.Ionics. 2019;25(2):849–857.
100.
HradilE, HradilH, WeisbergAM. Silver complex, method of making said complex and method and electrolyte containing said complex for electroplating silver and silver alloys. United States patent US 4126524A. 1978.
101.
GanH, LiuG, HuangC, et al.Surf Interfaces. 2021;27:101487.
Palomar-Pardavé,M, Ramírez,MT, González,I, et al.J Electrochem Soc. 1996;143(5):1551–1558.
130.
PolkBJ, BernardM, KasianowiczJJ, et al.J Electrochem Soc. 2004;151(9):C559.
131.
SanigarEB.Trans The Electrochem Soc. 1931;59(1):307.
132.
FletcherA, MoriartyWL. Gold electroplating bath and method of making the same. United States patent US 4168214A. 1978.
133.
OstrowBD. Bright gold and gold alloy plating baths. United States patent US 2660554A. 1950.
134.
OstrowBD, NobelFI. Electroplating baths for hard bright gold deposits. United States patent US 2967135A. 1961.
135.
StevensP. Electrodeposition of gold-palladium alloys. United States patent US 4048023A. 1977.
136.
WilkinsonP. Electrodeposition of gold alloys. United States patent US 4366035A. 1982.
137.
ShemyakinaEV, DyatlovaNM, FormenovAI, et al. Gold-plating electrolyte and process for preparing same. United States patent US 4497696A. 1985.
138.
NakazawaM, NishiyamaY, WakabayashiS. Electrolytic gold plating solution. United States patent US 4717459A. 1988.
139.
MorrisseyRJ. Non-cyanide electroplating solution for gold or alloys thereof. United States patent US 5277790A. 1994.
140.
KuhnW, ZilskeW. Cyanide-free electroplating bath for the deposition of gold and gold alloys. United States patent US 6165342A. 2000.
141.
ShindoY. Gold plating solution and gold plating method using thereof. United States patent US 6511589B1. 2003.
142.
UchidaE, OkadaT. Non-cyanide-type gold-tin alloy plating bath. South Korea patent KR100806697B1. 2003.
143.
KitadaK, ShindoY. Gold plating solution and plating process. United States patent US 6511589B1. 2003.
144.
HayashiK, HiroseY. Displacement gold plating solution. United States patent US 6767392B2. 2001.
145.
SanadaM, NakazawaM, ImafujiK. Non-cyanide electroless gold plating solution and process for electroless gold plating. United States patent US 7384458B2. 2007.
146.
SanadaM. Non-cyanide electroless gold plating solution and process for electroless gold plating. United States patent US 7264848B2. 2005.
147.
HinoE, KumagaiM. Electroless gold plating liquid. United States patent US 7300501B2. 2005.
CordonierC, HonmaH. Non-cyanide gold plating bath and method for preparing non-cyanide gold plating bath. United States patent US 9719183B2. 2013.
150.
NakazawaM, MasakiS, ImahujiG. Non-cyanide electroless gold plating solution and process for electroless gold plateing. South Korea patent KR20060051327A. 2005.
151.
NakamuraH. Non-cyanide gold plating bath for bump and wiring. South Korea patent KR101344018B1. 2006.
152.
YukiN, KoichiroI. Non cyanide gold plating bath for bump. Taiwan patent TWI477660B. 2008.
153.
LeeCG, MinjungK, BudukL. Non cyanide gold plating bath for bump and preparation method of bump. South Korea patent KR20090026075A. 2013.
154.
FurukawaM, MatsumotoT, KazuhikoS, et al. Non-cyanide electroless gold plating solution and plating method of conductor pattern. Japan patent US7264848B2. 2009.
155.
NiyuuhaheiR. New method for producing non-cyanide gold salt for gold plating. Japan patent JP2016094380A. 2014.
156.
MiyanagaS, OsakaT, KatoK, et al. Non-cyanide gold plating electrolytic solution. Japan patent JP2019214747A. 2018.
NeliasC, PommierN, DupratJJ. Alkaline, cyanide-free solution for electroplating of gold alloys, a method for electroplating and a substrate comprising a bright, corrosion-free deposit of a gold alloy. Patent EP2730682B1. 2012.
159.
JirongL, ZhenhuaD. Non-cyanide electroless gold plating solution and non-cyanide electroless gold plating method. South Korea patent KR101266901B1. 2010.
160.
XingqiaoH, HaoboC. The electroplate liquid and its electro-plating method of a kind of hard gold of non-cyanide plating. Patent. 2016.
InoueT, OkudairaH, TakeharaY.Super Stable Non-cyanide Electroless Gold Plating Bath Which Has Been Applied To Advanced Wiring Board Manufacture. 1st Joint International Electronic Manufacturing Symposium and the International Microelectronics Conference]1997.
169.
KosakiK, MatsuokaM, SeiwaY, et al.Stabilization of gold sulfite bath for microscale plating in Ga-As ICsFirst Symposium on Electrochemical Microfabrication1992.
170.
SmalbruggeE, JacobsB, FalconeS, et al.Electroplating of gold using a sulfite-based electrolyte.5th Annual Symposium of the IEEE/LEOS Benelux Chapter2000.
OsakaT, KoderaA, MisatoT, et al.J Electrochem Soc. 1997;144(10):3462.
183.
HiratsukaM, KurashinaT, NawafuneH.J Jpn Inst Electron Packag. 2002;5(1):72–74.
184.
PaunovicM, SambucettiC.Some environmentally conscious processes in electronic applications. Proceedings of the Symposium on Environmental Aspects of Electrochemical Technology: Applications in Electronics. 1997.
185.
RoyS.ECS Trans. 2009;16(36):67.
186.
RichterF, GesemannR, GierthL, et al. Cyanide-free bath for the elastic separation of hard gold layers. Germany patent. 1989.
187.
KatoM, NiikuraK, HoshinoS, et al.J Surf Finish Soc Jpn. 1991;42(7):729–735.
188.
InoueT, AndoS, UshioJ, et al.J Surf Finish Soc Jpn. 1998;49(12):6.
RenX, SongY, LiuA, et al.Electrochim Acta. 2015;176:10–17.
201.
RenX, SongY, LiuA, et al.RSC Adv. 2015;5(79):64806–64813.
202.
PearsonRG.J Chem Educ. 1987;64(7):561.
203.
JinL, LiuC, YangF-Z, et al.Electrochim Acta. 2019;304:168–174.
204.
YangY, HuW, YeX, et al.Adv Synth Catal. 2016;358(16):2583–2588.
205.
Colacio-RodriguezE, Salas-PeregrinJ, CarreteroMM.Monatshefte für Chemie/Chemical Monthly. 1986;117(8–9):941–947.
206.
ChenJS, FangYM, QiuQY, et al.Green Chem. 2011;13(9):2339–2343.
207.
HuD, LiuY, LaiYT, et al.Angew Chem, Int Ed. 2016;55(4):1387–1391.
208.
DimitrijevicS, Rajčić-VujasinovićM, AlagićS, et al.Formulation and characterization of electrolyte for decorative gold plating based on mercaptotriazole. Electrochimica Acta. 2013;104:330–336.
209.
DimitrijevicS, Rajčić-VujasinovićM, Jančić-HajnemanRM,
et al. Temperature effect on decorative gold coatings obtained from electrolyte based on mercaptotriazole – comparison with cyanide. International Journal of Materials Research. 2014;105(3):272–281.
210.
OhtaniY, SugawaraK, NemotoK, et al.J Surf Finish Soc Jpn. 2004;55(12):933–936.
211.
JinL, YangJ-Q, YangF-Z, et al.ACS Sustainable Chem Eng. 2020;8(38):14274–14279.
