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Plating problem

In spite of zinc plating of cup components in a barrel for 45 mins I am still facing problem of components getting rusted. Rust is visible within a week after plating.

SITCO
- Gangtok, Sikkim, India
2003

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Your question is broad, Mr. Sitco. You would need to hire a consultant, call in your chemical supplier, or at the least provide a lot more info. The parts probably do not have zinc coverage either because of inadequate cleaning and preparation or because of a deep recess and a plating solution that doesn't have much covering power.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
2003

HELLO SIR,

I have a plating shop in my unit and in spite of all the care, like proper cleaning, acid pickling in hydrochloric acid, maintaining the proper voltage and obtaining the specified current, the solution in the plating tanks tested and found okay. The components even after they are zinc plated are failing salt test within 24 hours. Storing the same plated yellow passivated components, tiny spots of rust appear within a month which later spreads into huge spots. Kindly suggest some solution to this problem. I even tried to increase the plating time from 45 minutes to one and half hour still it is failing the salt test. PLEASE HELP!

Regards,

SITCO
- GANGTOK, SIKKIM, INDIA
2003

Dear Sitco,

Check posttreatment after plating proper rinsing and drying of your parts . Go for thickness test I think if your pretreatment is perfect then you are not getting desired thickness from your chemistry. Optimize your chemistry and check your anode its working properly or not. If it is passive check your all electrical contact and if you can put lab analysis of solution here so it may be of great help. I hope you are using acid chloride bath.

Regards,

Qutub Saify
- Ajman, UAE
2003