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

Controlling parameters for Zinc plating process

Can anybody tell me what all parameters during plating and passivation we have to control to have good quality plating with SST of 120 hrs?

Sunil Patil
Mahindra - Mumbai, India
2005

---

2005

There's an old saying that "there's no harm in asking". And another one that goes "the only stupid question is the one you didn't ask". So we welcome your question, Mr. Patil. But on the other hand I have several books about zinc plating, each about 400 pages in length. Which of those 400 pages should I omit in my answer to you as irrelevant and unimportant to securing good quality plating?

The parts must be cleaned properly, they must be acid activated properly, they must be zinc plated properly, and they must be chromate conversion coated properly. For 120 hours you will need either a yellow or preferably an olive-drab R real hexavalent chromate conversion coating, or a proprietary trivalent replacement with suitable topcoat. Call in a process supplier and elicit their help in fine tuning the process control parameters for consistent quality. Good luck.

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

---

2005

Sunil,
You are not specific about your requirement.
What do you mean by 120 hrs SST? is it white rust or red Rust? This is a vast subject but as Ted said I will put it short.
As todays need is trivalent conversion coating,I will give you the following information.

Acid chloride Zinc + Tri blue+Top coat = 120WR/240 Red Rust
Acid Cobalt Zinc + Tri blue+Top coat =upto 400 hrs red rust
Alkalyne Non CN Zinc iron+tri black+ Top coat=500WR/1200RR

Your Company being one of the premier Automobile manufacturing co. in India,please ref.to GM specifications and there are proprietary chemicals available to cater your needs.
Good luck,

T.K. Mohan
plating process supplier - Mumbai, India