Letter 15006

Why does gold plating tarnish? 

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I have observed that the gold plating has some darkening areas over the nickel plated copper base material.

What causes this effect? We all know that gold is a very inert metal & does not corrode or rust. In this case, it should not tarnish. Under what circumstances or condition does this problem arises?

Your advice is greatly appreciated.

Thank you

Maung San Zaw
- Singapore

Hi,

Gold as such will not tarnish. It is inert. The tarnish like appearance is due to underlying surface getting corroded or oxidized. If the thickness of gold is not adequate and if the coating is porous, the corrosion taking place in the underlying surface may seem like tarnish. Ensure that you have adequate thickness build up of gold, to put an end to your problem.

Good luck ...

Karthik
- Singapore

Hi,

If you have nickel plating as a finish to plate gold onto it will normally not tarnishing even if you only deposit 0,1 micron of gold. This could mean that the gold plating solution has contamination, which tarnished. If you have nickel-free plating and plate gold onto copper or bronze the tarnish would come from the base if the gold plating is too thin to form a uniform layer without pores.

Good luck and all the best,

Trudy Kastner   electroplating service Durban, KZN, South Africa

Need to know about colouring gold (pink, green, red etc.) Would anyone mind answering this? Need information about the process of colouring gold.

Thank You,

Jayalakshmi. S.
- Banglaore, Karnataka, India

In general, gold coloring is done by alloying other metals into the plating. You will find some general info about this subject in the Metal Finishing Guidebook. But at this point you will find the subject to be within the domain of art rather than science, as the exact formulas are closely held, and I know of no articles in the literature exactly quantifying the coloration as a function of the alloying.

Ted Mooney, P.E.  finishing.com Brick, New Jersey

 

Why does pink gold plating tarnish? Now I have a problem about plating. Silver ring plated with pink gold. It is beautiful. but when I show it only 2 weeks, it is tarnishing. I think that because of my sweat or pink gold plating process or chemical of pink gold plating.
Please! anyone help me solve this problem.

Jane
Samuthprakran - Thailand

HI
I have the same problem listed above. My rose gold plating tarnishes very quickly and in some polluted urban areas it tarnishes a green and black color. Does anyone know why my gold plate would tarnish green and black? Its terrible!

Perhaps the solution does not have enough gold in it --too much copper alloy?
How can I check the solution that my plater uses?

Thanks for the input.

Vanessa
California

vanessa zeena
Artisté - California

Can anyone tell me if pure gold (such as a necklace) tarnishes in a swimming pool water that has chlorine?

Minou Sadeghi
- San Diego, CA, USA

Hi, Minou. 24 karat gold would nor tarnish, but jewelry is always made of a lower karat which contains copper or nickel or silver or other metals, and gold jewelry will tarnish in chlorine. However, the tarnish layer is probably thin and a jeweler can probably restore the shine with some polishing.

Regards,

Ted Mooney finishing.com Brick, New Jersey