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What chemicals react with chrome plated aluminum

Does anyone know if there are specific chemicals that encourage chrome plating to crack or chip? I have some chrome plated aluminum pieces that look like they were sprayed with some type of chemical and now they are chipping... Any ideas? Your help is GREATLY appreciated...

Sam Sem
hobbyist - Norcross, GA, USA
August 7, 2009

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Hi, Sam. This is kind of broad. Can you send a photo of them?

Regards,

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

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Decorative chrome is only a few mils thick.

There are a few contributing factors which could have caused your chrome pieces to chip.

If the part-to-be-plated is not properly cleaned, the metal will not stick, and easily chips/flakes off.

Diffusion is another possibility. (Active) Metals can dissolve into other metals, just like salt dissolves in water... but at a much slower rate. These form various peritechtoids along the plating surface, which can lead to weak spots, depending on the metal ratios.

To decoratively plate aluminum, the part must be zincated (zinc plating), nickel plated, and finally chrome plated. This leaves room for error at each of these steps; moreover, the risk of a weak peritechoid over time.

Robert H Kinner
- Toledo, Ohio
October 1, 2009