Electroplating Bismuth onto ferrous and non-ferrous metals
Q. What factors and precautions are involved in electroplating a surface finish of pure Bismuth onto ferrous and nonferrous metals? Are there any job shops that have the ability or experience with this task? Your assistance is appreciated.Edward T. Reininger
Systems R&D; - Long Beach, California
A. You might want a copy of Dingley, et al, Plating and Surface Finishing 63(4), 26, 1978 for a review of bismuth plating, as bismuth plating is not a commercial process. Lowenheim ("Electroplating" [linked by editor to product info at Amazon]) mentions that Bi plating might have "some minor uses in the electronics and nuclear energy fields".
Falls Township, Pennsylvania
(2002) -- this entry appended to this thread by editor in lieu of spawning a duplicative thread
Q. Is it possible to electroplate a finish of Bismuth metal as a substitute for lead? What would be the procedure and/or does anyone know a company that plates with Bi?Carlton Reininger
- LaCrescenta, California, USA
A. Bismuth is used as a substitute for lead in some solders and can be electrodeposited. It is, however, not a common process.
Lowenheim in Modern Electroplating suggested a bath of 40 g/l Bi2O3 with 104 g/l HClO4 and glue and cresol as additives. This is rather nasty as perchloric acid is prone to cause explosions. There is also a recommendation for NaBiCl4 with excess hydrochloric acid, but he concludes the perchloric acid bath is better for electroplating.
More recently a patent was granted for the use of bismuth chloride with various chelating agents; one such bath is 200 g/l potassium pyrophosphate, 35 g/l bismuth chloride and 10 g/l dextrin. The pH is adjusted with either HCl or NaOH, as required. Variations on this include the use of EDTA, with or without pyrophosphate, and gluconic acid as chelators. These baths can be: 1) EDTA 100-250 g/l; NiCl2.H2O 10-100 g/l; dextrin 1-50 g/l; pH 9-11; 2) 50% gluconic acid 100-300 g/l; NiCl2.H2O 10-140 g/l; EDTA 50-250 g/l;' dextrin 1-50 g/l; pH ~10, adjusted with HCl; 3) Potassium pyrophosphate 200 g/l; EDTA 150 g/l; NiCl2.H2O 48 g/l; dextrin 10 g/l pH 9-10. All these baths can be used either hot or at room temperature; if hot the ccd can be at least 50 ASF, but the colder bath prefers 25 ASF.
Bismuth can also be deposited by an electroless route. One prescription is: Bi salt 5-20 g/l; HCl 50-500 ml/l; Iodide 0-4 g/l; wetter <1 g/l; pH<1 temp 150±10 F. This uses an immersion time of 30 secs to 5 mins. Alternatively, dissolve 5g of Bi2O3 in 200 ml of HCl (conc.) and stir for 1 hour at 100 C. Add 100 g of 70% glycolic acid, with 100 g of N methyl pyralidone and 100 g monoethanolamaine. This is followed by 1 g potassium iodide. Dilute to 1 liter.
R&D practical scientist
Chesham, Bucks, UK
A. Hello Carlton,
Bismuth can also be brush electroplated. We currently have a bismuth brush plating solution that was originally designed to plate onto magnesium alloys. The bismuth solution, like most brush plating solutions, has a different chemistry than conventional tank plating solutions. This includes the solutions previously described.Chris Helwig
- Valencia, California
(2003) -- this entry appended to this thread by editor in lieu of spawning a duplicative thread
I am trying to carry out an experiment that involves the electroplating of Bismuth on a layer of metal. The Bi electrolyte is prepared by mixing bismuth nitrate with DMSO (Dimethyl Sulfoxide). The electrodeposition of bismuth onto gold surface is quite successful but when I replace gold with titanium, there is little to no deposition. I have seen many posts concerning the difficulties with electroplating on Ti. Ti is chosen as the seed layer because it can be etched away easily so are there any other metals that can be better substitute for Ti (must be able to be etched away easily) in the electroplating of bismuth? Therefore, my question is how can I electroplate Bismuth onto Titanium? Are there any good references for the electroplating of bismuth? Furthermore, if bismuth were to electroplated into extremely narrow grooves, what are the approaches you would suggest?
Thanks for all the help.Sean, Chen
McGill University - Montreal, Quebec, Canada
A. First of all, at what potentials are you trying to deposit bismuth onto titanium? What else does your solution consist of other than DMSO and bismuth nitrate? Titanium has a negative Redox potential, so it could be that you are oxidizing the titanium. I would guess though that you need to go to higher reduction potentials because there may be a large overpotential for the reduction of bismuth on titanium. Also, bismuth is very chemically sensitive so any etches that remove titanium are likely to remove bismuth as well.Akram Boukai
- Pasadena, California, USA
Q. I need to coat aluminum with bismuth. I followed the non-electric method above with "5g of Bi2O3 in 200 ml of HCl (conc.) and stir for 1 hour at 100 C. Add 100 g of 70% glycolic acid, with 100 g of N methyl pyralidone and 100 g monoethanolamaine. This is followed by 1 g potassium iodide. Dilute to 1 liter."
This seemed to work quite well, although not entirely knowing what to expect I think it is not right. I was expecting a shiny metal like finish. It plates very black and then dries gray with a grainy finish. I tested continuity and there is none. Is there a special pretreatment, should I plate the Al with another metal first, etc?
Thanks for all the help in advance!Jason Sanders
- Clarkston, Michigan, USA
Hi Jason. Yes, aluminum instantly forms a passive oxide layer, so it requires a special preparation cycle which usually involves immersion zincating followed by cyanide copper electroplating or electroless nickel plating before your final plating layer(s). Good luck.
Ted Mooney, P.E.
Pine Beach, New Jersey
November 21, 2010
Q. I had been looking for a method to plate with Bi, but it sounds like I need a different approach, as I am interested in a Bi or Bi - oxide(s) layer(s).
But I am also looking for a way to etch Bi and plate over Bi with other metals.
product designer - Menomonie, Wisconsin, USA
Want to avoid plating out bismuth in electrorecovery of precious metals
April 29, 2014
We're firing the plate residue in a furnace, using a silver inquart and picking up the bismuth of course in the silver. Been dissolving it in Sulfuric Acid filtering off the precious metals and precipitating the silver back. A long way around to get rid of the bismuth.Chuck Chase
mining and minerals - Baker City, Oregon, USA
A. Hi Chuck. I found a galvanic series that included Bismuth, and it was slightly less noble than copper. So your voltage sounds high since you want to keep bismuth from depositing. Can you possibly use a high surface area (sponge) copper cathode with tight anode-cathode spacing so you can reduce the voltage and make the conditions less favorable to the deposition of bismuth?
Is there any practicality to going through an ion-exchanger first, and then doing the electrorecovery from a regeneration/backwash that is more concentrated?
Ted Mooney, P.E.
Pine Beach, New Jersey
May 23, 2014
A. Hi Chuck
October 23, 2017
I'm a university student and I need to deposit thick layer Bismuth (>20 µm) through electroplating on Au (or Cu) sputtered substrate. What are best recipes and operative conditions for this process?
Thank you for your collaboration.
My best regards,
- Palermo, Italy
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