Where the
world gathers for metal finishing
Q&As since 1989


-----

Electrodeposition of NiCrAlY Powder

I am doing some test on electrodeposition of NiCrAlY on Hastelloy from Watts bath, but I observed that NiCrAlY powder is not imbedded in the nickel coating and it just sticks to coated nickel on the surface of the substrate.

Hatim Dafalla
- Dhahran, Kingdom of Saudi Arabia
January 18, 2011

---

January 19, 2011

How thick a layer of nickel are you putting on?
Have you done a metallurgical cross section of it?
It requires a fair amount of wetting agent and the NiCrAlY needs to be clean. Acid and peroxide is what I used on chromium carbide. Also, particle size is critical.

James Watts
- Navarre, Florida

---

January 22, 2011

Thanks for your answer; I am using AMDRY 962 (NiCrAlY).do you suggest a certain wetting agent that I have to try.

Hatim Dafalla
- Dhahran, Kingdom of Saudi Arabia

---

January 24, 2011

That is a material developed for thermal spray, typically plasma and not designed for co-deposition, but it may work.
Particle size was important in the carbide work that I did, 2-5 micron with 3-4 being the best. Too small did not work for that application and too big did not deposit well!
Whatever wetting agent (anti pit) you use will work.
Agitation is very important. On ours, the part rotated, it had a pumper plate and air agitation. The reason is that the solids sink out.
I had worked on a design that had an inclined bottom - like an inverted hip roof- with a welded on fitting for piping that would lead to a diaphragm pump which would disperse the material uniformly on all 4 sides of the top of the tank.
I was not allowed to build it for several internal / political reasons.
Like I said in the earlier post, we cleaned the powder with a dilute acid and peroxide mixture and we periodically had to reclean it as it picked up a slime. You have to watch the peroxide additions or it will heat up and put foam all over the place. We used 70% inhibited peroxide and that is not nice to work with.

So what is the end use of the part that you need the co deposition that you would not use a commercially available synthetic diamond process. I think that you used to be able to buy nickel plated diamond powder which should work very well.
Your process should be easier than the EN/ teflon co deposition which is available from several vendors.

James Watts
- Navarre, Florida

---

February 20, 2011

Dear James Watts,

Thanks a lot for your suggestions, I did it successfully.

regards

Hatim Dafalla
- Dhahran, Eastern, Kingdom of Saudi Arabia