The authoritative public forum
  for Metal Finishing since 1989
-----

Want formula for acid copper flash on stainless

Hi everybody

I need an acid copper flash recipe to plate copper over 316L. I have a depassivation treatment with sulfuric acid and cathodic current. After flash I plate copper with fluoborate.

Thanks

HECTOR LONGUEIRA
- ANTOFAGASTA, II REGION, CHILE
2005

---

Hopefully another reader will prove me wrong, Hector, but I don't believe that such a process exists.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
2005

---

THANKS TED, I BELIEVE YOU. MY REAL PROBLEM IS RINSING THE STAINLESS ENOUGH FOR AN ALKALINE FLASH WITOUT PASSIVATE IT AGAIN. I NEED PLATING COPPER ON SS WITH MAXIMUN CONDUCTIVITY.

THANKS AGAIN

HECTOR LONGUEIRA
- ANTOFAGASTA, CHILE
2005

In this case the clue is to rinse QUICKLY (slightly acidic water) and assure a COMPLETE and FAST coverage of the strike (cyanide). This is more easily said than done. Now, why wouldn't you prefer a Wood's nickel strike? From an electrical point of view, copper, indeed, has the high conductivity that you are looking for, but if the current has to travel through the interface into the SS substrate, the overall resistance of the path will be determined by the extremely poor conductivity of SS. The effect of an intermediate microlayer of nickel will be neglectible. More so if the current will only travel through the copper.

Guillermo Marrufo
Monterrey, NL, Mexico
2005