The authoritative public forum
  for Metal Finishing since 1989
  

  -----

Black Nickel Plating

1998

We are trying to quote an assembly to our customer which has a .008 thick stainless shell. The shell is shaped like an open ended box - .800 x .150 x .300 deep. It will be plated in a loose piece configuration. The specification received from our customer calls for 11.5 - 19 microinches Black Tin-Nickel over 38u" min Tin-Lead over 7 - 11.5u" Nickel.

I have not been able to find anybody who has ever heard of Black Tin-Nickel. Does such a plating exist?

If that plating does not exist, would anyone be interested in quoting Black Nickel over the specified underplatings? Quantities will be 5 - 10 million per year with 1 million piece releases.

Please let me know.

Mark N [last name deleted for privacy by Editor]
electronics - Landrum, South Carolina

Lowenheim, in 1978, "Electroplating", McGraw Hill ⇦[this on eBay , Amazon, AbeBooks affil links] describes a tin nickel bath, the deposit has interesting properties, he recommends a copper underplate for best corrosion protection, and ASTM Standard B 605 for more info. I don't know how to blacken this deposit. The finishing of that stainless box sounds like the outside would last forever. You would need a Woods nickel strike for good adhesion first thing, and that is going to drag out a lot of HCl which will be difficult to rinse (unless the box has a hole in closed end).

Maybe today, we should think about the new zinc alloys with a black post-treatment instead of tin nickel.They are very popular with the cable connector set. I am sure that several of the Suppliers in our directory can recommend the best one. There have been lots of letters about zinc alloys, maybe a search of our Hotline page would find something.

  
Tom Pullizzi
Falls Township, Pennsylvania

--
Ed. note: You may want to hear "The Lost Art of Tin-Nickel Plating".