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Small blisters on a new product only on the edge after annealing a nickel plated product

2006

I have a interesting question for you all after reading lots of articles on finishing.com,

We are a company which is plating for 50 years as a s small part of our total process. We use electrolytic nickel plating.

For a new product we have a blistering problem. But only on the edges.

As pre treatment we use:

1. Hot degreaser (1 hour)
2. Rinsing
3. sulfuric acid etching (5 min)
4. Rinsing
5. Hot degreaser (15 min)
6. Rinsing
7. Degreaser (20 min)
8. Rinsing
9. Electrolytical sulfuric acid etching (35%) 45 seconds
10. Rinsing
11. Hydrochloric acid (4 min)
12. (it is possible to use a nickel strike)
13. Electrolytical nickel plating 16V 300 A/h 900 A

We renewed all rinsing baths, made a new Nickel bath to be sure that there are no metal contaminations inside. We tried anodic degreasing all without success. We lengthened our etching time. We think it is not a pre-treatment problem anymore.

It's a round part of steel which from the inside to the outside has a layer thickness of 5 - 8 - 15 and on the outside like a coin 30 µm.

We tried starting with a low current to prevent burning the piece. We also had our product during 5 hours in a degreaser.

We tried a moisturizer to get a better spreading of the nickel layer. Not much effect. We use barrels.

It is probably a hydrogen entrapment but how is that possible and why only on the outside and what can we do to prevent this and what is cause.

Thanks in Advance.

Chris van Oene
Plating company - Amsterdam, The Netherlands

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Come back and give more information. What kind of steel? Leaded? Nickel bearing? What kind of nickel plating solution, metal concentration, temperature, pH, what kind of anodes, etc This sounds easy, just get us some more information.

Robert H Probert
Robert H Probert Technical Services

Garner, North Carolina

2006

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2006

Hi Chris van Oene,
All the efforts on ensuring good rinsing prior to plating is appreciated. This addresses a major issue. But then what after plating. How about the deposits after Nickel plating. What is the type of plating.
The problem clearly indicates that some acids or chemical substrates are left on the edges which are more prone to this defect after plating. Post rinsing and drying is also very critical.
Good Luck

Sanjeeva
Supply Chain - Bangalore, India