Home /
T.O.C.
FAQs
 
Good
Books
Ref.
Libr.
Advertise
Here
Help
Wanted
Current
Q&A's
Search 🔍
the Site

World's #1 finishing resource since 1989
No login needed: Chime right in

topic 1877

Plating on Stainless help



1998

Dear Helper,

We are doing small plating shop especially in gold plating. We are production company but also received recondition plating work.

Until now we got no problem in plating various metal except plating on stainless steel. We have tried some formula from several books, but until now was no satisfaction. We got problem of peeling after bubble present especially on the moisture contact area. Is that call the hydrogen embrittlement? We have tried to bake immediately after plating, but the happened come again.

Our procedure :

1. Soaking in 30 gr/lt NaOH + 30 gr/lt sodium carbonate (washing soda) [affil. link to info/product on Amazon] for 1-2 mnt. Wash.

2. acid dip 5 % H2SO4. Wash.

3. Activating Cathodically in 250 ml/ltr H2SO4^HCl, 5 A/ft€, 5 mnt.

4. Direct without washing to 0.4 g/ltr Copper Sulfate strike 750 ml/ltr H2SO4. 50 A/ft€ for 3 mnt. (We tried woods nickel strike, but it seem copper strike is better).Wash 2x.

** Direct go to step 7 or next:

5. Cyanide copper plating to 2 micron thickness (optional). Wash.

6. Bright watts Nickel Plating.Wash.

7. Acid Gold Strike (Citric acid base). Wash

8. Cyanide Gold Plating until 10 micron. Wash.

9. Immediately bake 300 °C for 2 hour.

The finish seem good and bonding well, but after 1 month bubble start come out at the moisture contact area.

Please help, Your advice is greatly appreciate.

Anton Bijosono
Ujung Pandang - Indonesia


1998

Wood's nickel strike should be used in step 4.

tom & pooky toms signature
Tom Pullizzi
Falls Township, Pennsylvania

1998

Definitely a Wood's strike, rinse rapidly but well and move with all due haste to the next plating tank. It takes very little time to passivate in air, especially if allowed to dry even a tiny bit. Works great. Use the lower limit of nickel and the middle limit of HCl and do not use sulfur depolarized nickel and carbon treat about once a month.

James Watts
- Navarre, Florida


1998

Thanks Tom & James,

I wrote a bit mistake about step 4, It should 0.4 gr/ltr CuSO4 + 750 ml/ltr HCl ( not H2SO4).

As I wrote, I tried use the wood's strike and the bubble still come. I wonder something wrong with my procedure.

Frankly, I didn't use deionized water for rinse. Is this the source of problem ?

Can you tell me if this problem is caused by Hydrogen Embrittlement or porosity ? The bubble & delay peeling only come out at the moisture contact area.

Anton Bijosono
Ujung Pandang - Indonesia


--

I do not know what you mean by "moisture contact area". Is this an area of the finished part which is immersed in water or a chemical in the field?

tom pullizzi animated   tomPullizziSignature
Tom Pullizzi
Falls Township, Pennsylvania

 


1998

Hydrogen embrittlement causes a weakening of the metal, normally along grain boundaries. Bubbles or blistering is caused by the part not being clean enough or active enough. You have not said what kind of SS it is. Very high nickel or very corrosion resistant SS like 316 or 321 may require a more aggressive etch.

If your part is a poor casting, you may be trapping gas in the pores and it is slowly causing the bubbles. A better surface finish may help. Grit blasting with Aluminum Oxide grit may improve the surface enough as well as give you an active surface to start with.

James Watts
- Navarre, Florida


1998

Thank's Tom.. The finish parts are Watch case, and the problem happened at the side that contact with skin.

Anton Bijosono
Ujung Pandang - Indonesia


1998

Hi,

Tom and Jim are right, step # 4 has to be a nickel strike. It is imperative.

You also need an electrocleaner. As you already have cyanide in your premises , a cyanide electrocleaner should be used. Make it up with sodium cyanide, sodium hydroxide and carbonate. Two electrocleaners, one cathodic and one anodic electrocleaners will be perfect.

I also noticed that you have no wetters in your soak. Try to add some.

Step # 3 and the copper plating can be omitted.

By the way, when do you notice the peeling, right after plating, after a thermal shock test or after usage?

sara michaeli
Sara Michaeli sara michaeli signature
chemical process supplier
Tel-Aviv, Israel



September 9, 2009

Hi, Anton. Let me make the score 4 to 0 that you must switch to Wood's nickel strike :-)

Please see Jack Dini's "Electrodeposition" for proper operating procedure and adhesion test results. Good luck.

Regards,

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

none
finishing.com is made possible by ...
this text gets replaced with bannerText
spacer gets replaced with bannerImages

Q, A, or Comment on THIS thread SEARCH for Threads about ... My Topic Not Found: Start NEW Thread

Disclaimer: It's not possible to fully diagnose a finishing problem or the hazards of an operation via these pages. All information presented is for general reference and does not represent a professional opinion nor the policy of an author's employer. The internet is largely anonymous & unvetted; some names may be fictitious and some recommendations might be harmful.

If you are seeking a product or service related to metal finishing, please check these Directories:

 
Jobshops
Capital
Equipment
Chemicals &
Consumables
Consult'g, Train'g
& Software


About/Contact    -    Privacy Policy    -    ©1995-2021 finishing.com, Pine Beach, New Jersey, USA