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


-----

PASSIVATION ON ZAMAK COMPONENTS

June 30, 2009

Dear Sirs,

We are the export arm of a manufacturing group in India. We have received orders from the US for the supply of Zamak 3 die cast components and sub-assemblies consisting of Zamak 3 die cast components and Zinc plated 4037steel, 090CRS steel, 090(13GA) CRS steel sheet metal components.

We are planning to pack each of these components in a plastic cover and place them in a small cardboard box separated by cardboard partitions. The small boxes would in turn be placed inside a large cardboard box and palletised.

Our manufacturer suggests that the components needs to be passivated to avoid formation of whitish layer during ocean transit.

Request your valuable suggestion if the above passivation would be necessary as well as adequate in preventing the formation of white layer / rust during and after the transportation of components , considering that they will be on sea for around 45 days.

Also kindly suggest if the packing with plastic covers will lead to any problems.

Thanking you in advance for your time.

Regards,
Giridaran

GIRIDARAN SUDARJANAN
Buyer - Chennai, Tamilnadu & India

---

Hi, Giridaran. Zinc plated parts are almost universally "passivated", i.e., chromate conversion coated. I would be shocked if yours weren't. Yes, the zamak components probably also require chromate conversion coating (or some other passivation treatment) to deter white rust.

Regards,

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