![pub](/gifs/pub.png)
Metal finishing Q&As since 1989
-----
Do Copper Braze Joints Present an Adhesion Problem for Alkaline Zinc?
2001
Do copper braze joints present an adhesion problem for an alkaline zinc line? The parts are processed as follows,
- Machined from low carbon steel tubing
- Brazed to an adapter (SAE 1015)
- Bent and packed for plater
- Plated Zinc with yellow chromate
- Powder Coated
After powder coat we are having blistering and poor adhesion only in the areas of braze flash or overrun. Our braze is 92% Cu and 8% Sn.
Any help, opinion, or feedback would be appreciated.
Kevin Davis- Versailles, Kentucky, USA
We plate parts that have copper braze with alkaline zinc all the time, so it can be done. Sloppy brazing will be a problem, however. We do not powdercoat after the zinc yellow, so I don't have specific knowledge about that. However, you should monitor your zinc bath and chromate bath for copper (and iron) contamination. You can do this with atomic adsorption (AA) equipment.
![tim neveau](../portraits/tim_neveau.jpg)
Tim Neveau
Rochester Hills, Michigan
2001
Q, A, or Comment on THIS thread -or- Start a NEW Thread