Metal finishing Q&As since 1989

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Grinding of chrome plating resulting in peeling off on titanium parts

March 1, 2010

Hi,

we are doing chrome plating on titanium parts.Thickness of plating is around 100 microns which is ground to the final specifications.During grinding operation peeling of plating is observed.Feed rate for the operation is 10 microns and wheel used is made specifically for titanium parts.Please advice as to why the problem could be happening.

Regards

Anoop Sasi
plating shop employee - India

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First of two simultaneous responses -- March 2, 2010

You need a wheel specifically for grinding chrome and not titanium. The substrate does not make a great deal of difference if the plating has been properly done. Titanium is one of the most difficult metals there is to plate PROPERLY. What is your process?

How much of the 100u are you grinding off? Are you absolutely positively sure that the part has been indexed in in the exact same position as when it was ground prior to plate? If the chrome gets thin on one side, it increases the probability that it will peel. For one aerospace company, we had to have 70u remaining on all sides.

Are you using the correct wheel speed? Are you using lots and lots of cutting fluid to keep the wheel/part interface as cool as possible?

James Watts
- Navarre, Florida

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Second of two simultaneous responses --

Getting good plating adhesion over titanium is very difficult, so what you are experiencing is not surprising. Tell us what your steps are before the plating tank and we will be able to advise you further.

Jon Barrows, MSF, EHSSC
GOAD Company

Independence, Missouri

March 3, 2010

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Hi,

I'm also like to know the pretreatment steps, because that it very difficult to get a really good adhesion on titanium. It not sounds to me the grinding is too hard. I think that the adhesion between chrome an titanium is bad. Why did you plate so much as 100 µm if the part only should have 10µm when it finish. I'm also think the chrome deposit may have a better adhesion if the thickness will be thinner.

Regards

Anders Sundman
4th Generation Surface Engineering
Consultant - Arvika,
Sweden
March 6, 2010