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

Black Cadmium help

 

I am currently acid cad plating then turning parts black in a moly based product. I am getting very poor adhesion of the black. I have tried many different activation steps with no success. I am looking for either someone who has done this process and can offer some advice or a suitable replacement for the black parts(not a chromate).

Thanks,

Steve Kingsley
- Urbana, Ohio, USA

---

It is very easy to get too much brightener in acid cad, which puts excessive organics in the cad which makes adhesion of even chromates difficult. You may have to strip all of the additives out and replace them doing a lot of hull cell testing to find the minimum that you can get by with. As the bath ages, it takes an ever increasing amount of brightener and carrier to maintain a smooth finish, thus the need for carbon stripping once in a while. James Watts
- Navarre, Florida