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


-----

Surface Rust on Nickel Chrome Plating

We are having some of our products plated with a Duplex nickel chrome trivalent chemistry. Within 24 hours after plating there is evidence of small rust spots showing through the chrome layer. What factors could be causing this rusting condition?

Dennis Bayle
Quality Manger - Grand Haven, Michigan, USA
August 21, 2009

---

Hi, Dennnis. Unless the shipping or storage situation is outrageous, there is something seriously wrong with parts that rust in a day! If your plater cannot immediately address this problem with you, you need another plater. Duplex nickel-chrome is used on truck bumpers and auto brighwork to last a decade and more in the worst possible outdoor exposure.

Regards,

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
August 25, 2009

---

First of three simultaneous responses --

My guess is that there are rust pits in the material before the chemical processes. They can be extremely difficult to chemically remove.
Combine this with very thin layers of nickel and chrome, and the rust will rapidly come thru as the pits will trap liquid.

James Watts
- Navarre, Florida
August 25, 2009

---

Second of three simultaneous responses --

Another possible answer is that the trivalent chrome is seriously contaminated with iron. The deposit make look fine and the bath have very good throwing power. But the iron in the deposit may rust giving the effect that you describe.

Harry Parkes
- Birmingham, UK
August 26, 2009

---

Third of three simultaneous responses --

The chrome process used is a trivalent one.
This is a whole new story.
It is a much more complicated processs to run.

It need constant supervision and most of it, it needs a post dip.

Sara Michaeli
Tel-Aviv-Yafo, Israel
August 26, 2009