Can electroless process or electroplating deposit Inconel 625?

A. There are no electroless processes for depositing alloys like Inconel.

A. Sorry, Arun. Inconel and other nickel-chrome alloys (including stainless steels) cannot be produced by electroplating from a hard chrome plating bath or any other plating bath. Dr. David Lashmore, then of N.I.S.T., did produce an experimental multilayer plating with dozens of alternating microlayers of nickel and chrome, as an attempt to simulate stainless steel, but that's the closest anyone has come.

Regards,

A. Hi Rohit. No, there is no known way to do this. The operating conditions and solution concentrations required for reducing and depositing chrome are so radically different than the conditions for depositing nickel and iron that it just doesn't work at all :-(

Regards,

Could you please elaborate it a bit?

A. Hello again Rohit. Very few alloys are electrodepositable: the electrochemical deposition potential of the two or more metals may differ by too much, or the conditions necessary to get an electrodeposit of one may preclude the simultaneous deposition of the other.

Brass, which is an alloy of copper and zinc, is an alloy that is electrodepositable; and it's remarkable that it is -- so let's use it as an example to explain why alloy electroplating is difficult yet brass plating is possible. Children make "lemon batteries" by inserting a copper electrode (such as a coin) and a zinc electrode (such as a galvanized nail) into the fruit. The copper is so noble and the zinc is so active that this battery will generate about 1.1 volts (look up their electrochemical potentials).

What happens with the copper-zinc battery is that some of the copper atoms on the surface of the copper electrode ionize into positively charged copper cations and migrate toward the zinc electrode. When they get there, they steal electrons from the zinc, and they turn back into copper metal as a deposit on the surface of the zinc. This results in an excess of electrons on the copper electrode and a deficit of electrons on the zinc electrode, but the electrons (current) can flow through external wires to correct the imbalance of charge and provide power.

So copper will deposit onto zinc without any external power applied. If you want to electrodeposit zinc onto copper, you need to apply in excess of 1.1 volts to make the current run the other direction, so zinc atoms are ionized into zinc cations, migrate through the solution to the copper electrode and meet up with an excess of electrons so they convert back to atoms.

Now, imagine you want to electrodeposit brass onto a steel part. Although you apply current, you can't control individual atoms, so the steel becomes covered with copper, not brass (anytime a zinc ion tries to deposit, there is a 1.1 volt difference causing a copper ion to deposit instead). Thus it is not possible to plate brass onto steel using lemon juice as the electrolyte. But if you move on to "the Nernst equation", you will see that if the concentration of zinc ions in a solution is tens of thousands of times higher than the concentration of of copper ions, this 1.1 volt potential difference can be reduced to zero. It happens to be possible to "complex" copper ions with cyanide in order to reduce the number of "free" copper ions so dramatically that brass plating is possible.

No such complexing is possible to render chromium, nickel, and iron of equal potential to allow alloy plating. Plus the required deposition conditions are radically different. Chromium will not electrodeposit at all except under very special conditions; those conditions include no nickel or iron in the solution. Good luck.

Regards,

Thank you so much Mr. Ted Mooney for your descriptive explanation. Now, I understood your point. Thanks again.

A. Just to add to this thread whilst doing some of my own research that while you can't electro-plate Inconel it can be 'metal sprayed'.

There are coating powders which match the attributes of 625 and 718 and are applied through High Velocity Oxygen Fuel. This may be another route where you require additional wear and corrosion resistance but will come at a significantly higher cost (just had this quoted in fact)

For many applications I have always found High Phosphorus Electroless Nickel and Heat Treatment to be a good combination depending on your material etc.