Ask the Expert Question-and-Answer Archive
(Hard Chrome Plating)

by Larry Zitko, ChromeTech, Inc.
September, 2002

Plating/Stripping Chromium on Tungsten

Q. We have some tungsten parts which have been plated with chromium plating. The plating needs to be removed and replaced.

First - What stripping solution/method would be less likely to etch the base material of the tungsten part?

Second - What is the best activation to use for chrome plating on tungsten?

I have no experience with plating chrome on tungsten, and could not find any reference of it in my library or on-line.

However, I did find a reference to plating nickel on tungsten. In the "Shop Problems" section of the March 1987 issue of Metal Finishing Magazine, a reader asked how to plate nickel on needles made of tungsten alloy. The author provided the following sequence:

1. Anodically etch in 4 oz/gal potassium hydroxide solution, 120-140 deg F. for 2-3 minutes.
2. Rinse
3. Neutralize in 10% sulfuric acid solution.
4. Strike immediately in 33 oz/gal chromium plating bath with 100:1 chrome-to-sulfate ratio.
5. Immerse in 20% hydrochloric acid for 2-5 sec.
6. Rinse
7. Nickel sulfate strike.
8. Nickel plate.

If you consider the first 4 steps and ignore the remaining steps, it looks similar to your application, except that your thickness of chromium would undoubtedly be greater than the chromium strike.

I hope this research and reference will be of assistance.