Required solution temperatures for electroplating and electroless plating

A. Hi Barbara. Yes, but what that temperature should be depends on a lot of factors including the general chemistry, whether you seek a bright or matte deposit, etc. In general, suggested plating temperatures for various plating solutions could be anywhere from 60 °F (some organic brighteners decompose at higher temperatures) to about 160 °F. The vendor of the plating solution should be able to give you the optimum operating temperature.

Typical cyanide silver plating solution temperatures are 75-90 °F. Non-cyanide proprietary silver plating solutions (which would be safer and far preferable in a non-industrial setting) must be per the vendor suggestion. Gold plating solutions are highly variable, being of alkaline, neutral, or acid types with suggested temperatures running the full 60 °F to 160 °F gamut. Good luck.

A. Hi Don. For the Electroless Nickel, a great reference would be "Electroless Plating" by Mallory & Hajdu.

For alkaline baths it offers the following graph --

Obviously, the higher the temperature the better, except that spontaneous plateout can result from over-temperature.

Electroplating is very different though. For electroplating, the deposition is directly proportional to amp-hours applied (per Faraday's Law), and nothing else (including temperature) matters in that theory. But, in reality, higher temperatures offer greater ion transport rates in the bulk of the solution as well as across the boundary layer. And the reason ion transport rate matters is that the electrons on the cathode will reduce something . . . if insufficient metal ions are present, the electrons will be wasted liberating hydrogen from the water in the solution. How much metal is actually deposited compared to Faraday's prediction is called the "efficiency" of the plating bath, and for some plating solutions it will approach 100% at low plating rates and high temperatures, but will drop off at higher plating rates and lower temperatures.

Regards,

Ted:
You have been quite helpful. The reference, and especially the graph, tell me much of what I need to know. Your text helps a bunch, too.Thank you for the time and interest you have given to my problem.

Cheers

Sorry, Don, that's not within my area of expertise. But if no one else answers, and you don't find the answers in Mallory & Hajdu, another good reference is Gawrilov's "Chemical (Electroless) Nickel Plating."

Regards,

Ted:
Thanks, again, for your much needed help and the good references. I will read up a bit better and then run the problem through the analog computer. That is, do the experiment and see if I can solve the problem the cut and try way. This is, of course, the final arbiter of these things.

Cheers,