What causes blistering of nickel plated parts?

A. Nickel blistering can be caused by numerous things. It can be caused by hydrogen entrapment and subsequent release, especially during any heat treatment. It can also be caused by stress in the deposit and poor cleaning/rinsing. If you have a blistering problem, perhaps more information about your process may be beneficial.

? What is the substrate and what nickel bath are you using? It may be a good idea to give your whole process details.

A. Sounds like an accumulating problem, so it is probably contamination from somewhere entering your tanks. Look for liquids or oils dropping in from the plant or the ceiling. Also check your rinses are working as well as they should.

A. You should not use a drag out after semi bright nickel. You should enter the bright nickel directly after the semi nickel. No rinse between them. The rinse between them and the time it takes, can passivate the semi bright nickel layer. The PH of the semi bright nickel has to be lower than the PH of the bright nickel.

A. As far I know, most of blistering problems come from pretreatment. Maybe there is problem with etching/cleaner before plating so plate materials were not clean enough before running in plating bath. Some etching/cleaner chemicals have limited life time, so it must frequently changed, especially if there are lot product.

A. Mr Mumtaz Ali.

The reasons for Bright nickel peel off from Semi bright Nickel on a continuous line are shown below...

- Very Hot parts exiting SB Nickel drying on transfer leading to passivation of the SB nickel and consequent passivation. This causes peel off between layers.
- Parts becoming Anodic on exit and Anodic on entry, which leads to passivated Nickel and subsequent de-lamination due to poor adhesion caused by the un active SB Nickel.
- Sometimes Excess Brightener, or excessive Organic breakdown products will cause passive deposits.

The solution for the first situation to lower temp in SB Nickel or reduce transfer time. Or a bit of both and ensure parts enter the Bright bath wet.

A drafty plating plant is prone to this problem in Windy weather causing dry parts on Transfer and consequent de-lamination.

The solution for the second situation is to ensure live current exit and Live current entry. Parts must be cathodic on exit and cathodic on entry with a low PD of 1 to 2 volts from an auxilliary source. This will shut off before the Flight bar sits on the V blocks or flat blocks ..or the Bus bar. Live current entry is the best solution to anodic passivation of SB Ni plated parts on an automatic line.

The solution to the third problem is to reduce brightener levels and adds to recommended levels. To remove organics, run carbon very regularly and maintain adds per data sheet levels.

Bath pH in SB is important. Maintain pH within recommended levels and ensure solutions are well protected from organic overloads.

Lastly, don't hesitate to treat the solution with Peroxide if the organics get too rowdy.

I hope the suggestions help.
Regards

A. Hi Marco. You must first determine in what layer the blistering is occurring. When a blister is popped, do you see zinc or copper or nickel on the part and on the underside of the blister?

Are you barrel plating or rack plating?

How do you know that your nickel plating rectifier has not gone bad?

If you have no confidence in your nickel plating bath supplier, you must find another one.

Regards,

A. Hi Klaudia. Your question is very welcome, but it's a consumer question posted against a fairly technical discussion by hands-on electroplaters, so we hope we haven't lost you :-)

You have 5 blisters in the last six weeks, and the unit is only two months old if I understood correctly. Blistering is virtually always a manufacturing defect, and there is nothing you can do to slow it -- so I think you should try to get your money back. Good luck.

Regards,

A. Hi Mr. Monshoe. The fact that you discovered contamination in your copper plating rinse tank and a defective R.O. system and fixed those problems is good! But discovering problems there is not proof that those problems were the cause of the blisters :-)

You apparently, unless I am misunderstanding, now have a copper activation tank which you are confident of, but still have the nickel adhesion issue. Have you carefully examined the underside of a good number of blisters and found them to be nickel with no copper at all, and have you carefully examined the 'raw skin' under a good number of blisters and found them to be copper, with no nickel? One good thing about blisters is they often tell you which step is problematical.

Re. your second question, apologies but please search the site for "plating on plastic" or "PCABS", and if you don't see the answers you seek, post your questions on a related thread. Sorry, but if our threads wander too much, the site won't help readers because it'll become a rat's nest of 60,000 threads, each about everything, where no one can find anything :-)

Luck & Regards,

A. Hi, blistering of nickel on any substrate is often due to poor surface conditioning and/or contamination. I suggest that you check that all your pretreatment solutions are in specification and are working properly. Secondly check for contamination in your rinse tanks -- even if your pretreatment tanks are OK, if your final rinse tank before nickel plating is contaminated with something such as oil or grease, all your pretreatment has been a waste of time because you are taking contaminated parts into your nickel tank. Make sure all your rinse tanks are working properly and that the rinse water is free of contamination (oil; grease etc). Also check that your workpiece is wetting properly - do a surface wetting test on it.
Check your nickel tank is working properly - do a Hull cell test on it. Also check that the solution is in specification -- remember that nickel electroplating is only 97% efficient, with the remaining 3% being hydrogen discharge, which could help cause the blistering; this can be further manifested if the pH is too low.
Remember - in society, cleanliness is next to Godliness, but in electroplating - Cleanliness is Godliness!