Sound technical content, curated with aloha by
Ted Mooney, P.E. RET
Pine Beach, NJ

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Electrolytic zinc plating and raw material relation

Hi,
We are a coating factory, and we coat fasteners. My question is about electrolytic zinc coating and the fastener's raw material. What could be the maximum Silisium, Phosphorus and Manganese content in metal raw material? Thanks for your help.

Fatma Babacan
plating shop employee - Izmir, Turkey
October 6, 2010

Hi, Fatma. Best of luck but I don't think your question will draw a response because I don't think technical papers or charts are written in that fashion. If you can tell us what you do (rack or barrel plating; acid, cyanide, or alkaline plating), what problems you experience, and why you suspect these 3 materials as the culprits, I think you will get some good replies.

Regards,

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
October 6, 2010

Hi Ted,
We have acidic barrel zinc electroplating process. We seen from our experiments that; in raw materials which has greater than 0,08 Silisium content, there is a coating heave. and the coating in bolts are flaked off. Could you please tell us is there any Si content limit in bolts' raw material? Thanks for your help.

Fatma Babacan
plating factory - Izmir, Turkey
December 17, 2010

Hi, Fatma. I am not familiar with this being a problem, although someone more knowledgeable than me may be. What I would suspect is that the fasteners with a higher silicon content underwent different manufacturing processes and their dirt and smut are not as easily removed in your pretreatment cycle. As a test, try to scrub a few of the silicon fasteners with pumice before sending them through the plating cycle, and see if this relieves the blistering. Good luck.

Regards,

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
December 20, 2010

January 2, 2011

I would like to suggest to add flash Zinc plating.

Process Sequence:-
Cleaning
Rinse
Rinse
Pickling
Rinse
Flash Zinc Plating (for 10 min.)
Rinse
Stripping
Rinse
Rinse
Then regular Plating

You can try it you will get better results.
Regards,

Parashar S R

Sanjeev Raman Parashar
- PUNE, Maharashtra, India

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