Nickel Plating Turning Blue

[Vindicit]

Hi all, I have parts being Nickel plated to AMS 2424 about 0.002-0.004 thick and being shipped over seas from the UK to the US. They have a post plating heat treatment thats at something like 900F (500C) for an hour. Typically theres a good amount of my parts that have a blue blotchy stain on them. What can turn Nickel blue? Is it a tarnish? Is it from acids or oils? People handling parts with their bare hands? Is it the heat treatment?

 

[btrueblood]

Pictures would probably help quite a bit. Funny how in an age when cameras are literally within arms reach of 95% of us, so few pictures get taken.

900F is awfully high temperature for a post-plating hydrogen bakeout. But I would expect an oxide tint to be pretty uniform over the whole part, not blotchy. Does the color wipe off with water, alcohol, ammonia water, or vinegar?

 

[Vindicit]

Id love to freely just get you guys pictures but because these are aerospace parts theres rules about which parts can be shown and which cant so until I can get that information we'll just have to make due.

 

[WKTaylor]

Vindicit...

AMS2424 does NOT specify a post-plating bake anywhere close to 900F. WHY are You doing the post-plating bake?

I assume that the base metal is tolerant of the 900F bake, such as 9-Ni-4Co-.3C [etc], A286, etc?

Regards, Wil Taylor

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[EdStainless]

250-300C is the aging temp for Ni-P.
Are you sure that it isn't 500F and not 500C?
There are plenty of Ni compounds that are blue, I am guessing residue from cleaning or plating.
Does it wipe off? Is it on the surface, any loss of adhesion?

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