Non-cyanide silver plating baths?

A. Hi, folks. EPI / Electrochemical Products Inc. [a finishing.com supporting advertiser], Technic, Zinex, and possibly others, offer cyanide-free silver plating baths. Usually these have been restricted to electronics applications rather than decorative use as the color is a bit "off" -- but we may need to start accepting it even if the color is slightly different.

Regards,

A. Technic is one company that sells that product. They call it cyless silver. I think that they were the first major company to market a cyanide free silver.

A. Ebrite 50/50 an alkaline non-cyanide silver is being marketed by EPI / Electrochemical Products Inc. [a finishing.com supporting advertiser]

A. Pyrophosphate silver bath:

potassium pyrophosphate.......100-350 gm
ammonium carbonate...........20-145 gm
silver pyrophosphate..........15-90 gm
water.........................1 lit
SS anode

A. You can try with potassium ferrocyanide silver plating bath:
40 gm silver chloride
200 gm potassium ferrocyanide [affil links] 2
0 gm potassium carbonate
stainless steel anode
0,5 A/dm2-3V-20° C (temp.)

A. Hi, Ido. There are commercial non-cyanide silver plating baths available from such suppliers as EPI / Electrochemical Products Inc. [a finishing.com supporting advertiser], Technic, and Zinex.

However, these have usually been reserved for electronic applications as even the vendors acknowledge that the color isn't quite right to match conventional cyanide silver plating. But things are always getting better and you can certainly try them. Good luck.

Regards,

A. Some cyanide free silver plating baths:

Ferrocyanide bath:
10 gms silver chloride
20 gms potassium ferrocyanide [affil links]
20 gms potassium carbonate
1 lit water,SS anodes

Pyrophosphate bath:
15 gm silver(in nitrate or phosphate salt)
100 gm potassium pyrophosphate
25 gm ammonium carbonate
1 lit water

Ferrocyanide-sulphite bath:
add 40 gm sodium sulphite to previously described ferrocyanide bath

A. I'm in a similar situation, except mine is with silver sputtered copper masks. I've been researching this problem and have found a lot of valuable information online at Dicks Encyclopedia from the year 1875 this was an unpublished book. I also found information from The Household Cyclopedia-Metallurgy. Just a little information; Nitric Acid with a specific gravity of 1.5 acts on silver but not copper; it renders copper more electro-negative than before, less oxidizable and deprives it of the property of decomposing the acid and precipitating the silver. Silver nitrate is nothing more than silver suspended in solvent (a solvent made of acid which can be very exothermic and nitrous). According to these documents. The silver can precipitated out by using NaCL (purified table salt) which throws it down into the bottom of the pot as silver chloride. The chunks of silver chloride when removed must be rinsed by distilled water and placed in a zinc cup and continually rinsed to remove the chloride leaving almost pure silver. To purify it more it must be boiled in Potash (potassium sulphate) to remove the rest of the chlorides along with a dash of sugar. There is already equipment manufactured in USA to help remove the silver from silver nitrate called Hallmark Refining they have piece of equipment called the Mark7.

A. Maybe you can use sodium thiosulphate [on eBay or Amazon] ?! According to title of your question you can use potassium ferrocyanide [affil links](less than 1% of potassium cyanide toxicity), thiourea [on eBay or Amazon], pyrophosphate, iodide, sulphite or thiocyanate solution (rhodanide). Good luck and hope it helps!

A. Pure silver is manufactured with electrolysis out of an silver nitrate solution. The only thing you have to look at is , that silver, which is deposited out of a silver nitrate solution won't form a homogenous layer, there will be a crystalline growth. This crystals have to be removed from the cathode before they reach the anode .

You should be able to find more information like voltage to use , concentration and working conditions if you look for purification of silver, every better chemistry book should be able to give you some help.

A. The simple way is to throw in 00 steel wool [on eBay or Amazon] and filter the silver off or add sodium chloride and precipitate silver chloride. Dissolve the chloride in sodium thiosulphate [on eBay or Amazon] and electrolyse. This is how the photographic industry gets silver out of used fixer and commercial equipment is available.I can think of no way that cyanide would help.

Note; DO NOT electrolyse the nitrate solution. When most of the silver has been removed, the nitrate is electrolysed to ammonia [on eBay or Amazon] which can react with the silver to produce a variety of highly explosive silver/nitrogen compounds.

adv.
EPI / Electrochemical Products Inc. [a finishing.com supporting advertiser] offers cyanide-free silver plating processes.

A. When you talk to them, get a complete process for plating silver on copper. I think that you will need a silver strike and probably a nickel strike. I am not aware of any non cyanide silver strikes. They may have work around methods.

Their web site says that their 50-50 solution will plate directly to copper. Ask them if the copper does not migrate thru the silver over time.

A. Monovalent silver metal which is complexed by a thiosulphate ion is developed as a cyanide-free silver plating process. Such electrolyte is operating at acidic pH with a stabilizer of an organic sulfinate compound. Suitable compounds include those having the formula R-SO2-X wherein R is an alkyl or aryl moiety and X is a monovalent cation. The stabilizer is present in an amount sufficient to stabilize the thiosulphate ion when the solution is operated at an acidic pH.