What kind of plating is this?

Just took this wheelnut off:

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You can see the original plating inside, but it's all rusted away on the outside. The plating looks yellow. I'm curious: does anyone know what kind of plating it is?

Best wishes,

Chris

Reply to
Christopher Tidy
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Yellow cad?

Reply to
Gerry

I wondered if it was cadmium myself. But I thought cadmium was poisonous. Is it still used? I've recently seen the same colour plating on brand new items.

Best wishes,

Chris

Reply to
Christopher Tidy

Think I just answered my own question. Here's a good article on the subject:

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Looks like it's probably zinc dichromate.

Best wishes,

Chris

Reply to
Christopher Tidy

The irridite finish can also be applied to zinc plating as I recall. Cadmium has fallen out of favor, although it is likely still used for defense purposes.

Harold

Reply to
Harold and Susan Vordos

Can somebody explain this bolt, which is from the above link about coatings?

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Reply to
Cydrome Leader

Those look *like* threads but I don't think they *are* threads.

Dave

Reply to
spamTHISbrp

I read a lot of requirements specifications these days and Cadmium is on the prohibited materials list. But you can get permission to use just about anything if you convince the procurement office it is in the best interest of the military.

Carl Boyd

Reply to
Carl Boyd

Phosphate coatings often are yellow, and they can be (and often are) applied on top of plating.

-- Ed Huntress

Reply to
Ed Huntress

Those look *like* threads but I don't think they *are* threads.

They are threads, but I'd guess they're not of any practical use. At a glance, I would say it's a cylinder head stretch bolt, and the 'threads' are possibly added to modify the stretch properties of the bolt.

Reply to
moray

Here are a couple more interesting links I found:

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Chris

Reply to
Christopher Tidy

Right. Zinc plating affords good rust protection, but it is very vulnerable to even mild acids like fingerprints and acid rain. A dunk in the chromate give the zinc better resistance to mild acids.

Reply to
Don Foreman

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