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Blisters in Nickel Plating with temperature

Q. We have a problem that we hope someone can help us, we are a job shop plater and we are Nickel plating Zamac (Zinc Die Casts) parts that have a good die condition. Parts are processed in racks and mainly they are a plate 1/8" Thick approx.

The problem is our client welds in a reflux oven the parts and they go up to 225 °C (437 °F) for 4 minutes. The initial samples 160 pieces where perfect, the we sent 1400 and 5.7% had problems with blisters, then we sent another 3800 parts, and out of 100 samples, 24% had blisters after the reflux welding.

our Process is:
Degreaser in process for Zamac, 60 gr/lt and 60 °C Rinses
Activate with Acid Salt 30 grms/lt temp. ambient
Rinse
Alkaline Copper 10 minutes 60 °C
Rinses
Activate in Sulfuric Acid 5% amb temp
Nickel Watts
Rinses

Please any feed back will be very good. We haven't received the parts to examine them for the blistering, to see if it comes from the base metal or the copper.

Thanks for your help

Sergio Hernandez
Plating job shop - Guadalajara, Jalisco, México
2005

A. 10 minutes copper plating sounds too little. I would try a heavier copper plate first. The acids may be attacking the Zamac, and causing poor adhesion which results in blisters later. Jeffrey Holmes, CEF Spartanburg, South Carolina A. The problem is probably one of two things 1. Porosity in the casting entrapping solution/dirt before nickel plating 2. Lead in the casting requiring a fluoboric acid dip in addition to the acid salt. These would be the most common if the blister is copper from the die cast. It would be necessary to look at the back of the blister to determine what exactly is blistering. Gene Packman process supplier - Great Neck, New York A. Looks like liquids got entrapped under the plate. Subsequent exposure to high temperature made them expand or boil. So, my suggestion would be to inspect for pores or cracks before processing. Also, it may be beneficial to add an electrocleaning step after the degreaser. Guillermo Marrufo Monterrey, NL, Mexico

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A. Sergio, Are the blisters peeling off down to the substrate (zinc) or is the nickel peeling and leaving copper? Other than the heat, my process is very similar to your (I use a copper cyanide bath...is this what you mean by alkaline copper?). I've never experienced this problem if the line specs are OK unless I had some very porous castings. Trent Kaufman electroplater - Galva, Illinois A. Guadalejara ! Blister problem after copper plate, 1) peel the blister then check the on die cast if it is black spot, make sure activation good ,check the concentration of your acid salt tank and dumping and make up new schedule. check the copper strike for any other contamination like chrome ,analyze the copper strike for detail contamination. Popatbhai B. Patel electroplating consultant - Roseville, Michigan

  Thank you for all your responses.

I did what was suggested and peeled the blister, we found a grey-ish color in both parts of the blister. Photo included. There is no Copper in sight and the color is grey, as the die cast. Not black as if with smut.

Gene, if the problem is not copper from the die cast, what should we do?

Guillermo, in reality the bubbles only appear after the high temperature. There are no pores visible in the die cast.

Trent, the blisters are peeling off down from the substrate, see photo. what can we do?

Yes our alkaline Copper is a copper cyanide bath, (it's not a strike)

Can you help me with the lone specs for his work?

Thanks again to all for your time and help.

Sergio Hernandez [returning]
- Guadalajara, Jalisco, Mexico

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A. Hello Sergio, Please check that the casting is not laminated. If it is cast in the Hot Chamber process the castings should be allowed to cool naturally in air. Water quenching is entirely avoidable. Recheck for Porosity by taking a light cut with a 120 grit polish belt or wheel. If pores show up below the skin you need speak to your casting department. Lastly do add a cathodic and an inhibited alkaline anodic cleaner in sequence after the soak cleaning stage. After the acid activation the zinc should appear clean whitish signifying good activation. Two rinses are required thereafter. Add an acid copper step after the cyanide copper stage and plate at least seven and up to 20 microns leveling acid copper for a really excellent finish. Good luck. Asif Nurie [deceased] [deceased] - New Delhi, India With deep sadness we acknowledge the passing of Asif on Jan 24, 2016 A. Sergio, I run into delamination problems on my die cast parts once and awhile. Depends on the porosity (not always visually apparent-the casting sometimes seem to have a very thin "skin" on them that covers the voids) of the part. We have had some moderate success buffing the parts before processing. I would go to the root of the problem and try to work with the caster to improve the part quality if possible. If this isn't possible, you may try pre-baking a batch of parts before plating. You are stuck between that old rock and a hard place. Good Luck Trent Kaufman electroplater - Galva, Illinois

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Q. Please tell me the lead in diecasting, which comes off with the dip in fluoboric acid with the acid dip?

Please tell me if it is before copper plating or after copper plating?

Abhishek Bhati
- Ghaziabad, UP, India
March 25, 2012

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Blisters in Nickel plating on diecast parts

Q. I am looking for help: my supplier for all the sudden begun making "blisters" in QQ-N-290 over 0.007 mm copper on die cast part Zamak 5.
They were doing fine for over the year and now 60% parts are having blisters.
Blisters are developing on part in time: holding control sample @150 °C for a day will accelerate blister forming.
Supplier is in China, one part having problem, another does not, both plated on same line. We already went through usual suspects: cleaning parts prior to getting them into plating line, tank control etc.
Still one part is almost 100% yield, another 60% scrap, parts are barrel plated.
If anybody willing to share their experience or may suggest what else to look at.

Mark Berg
Product designer - Hudson, New Hampshire US
November 28, 2017

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Q. Dear sir.
I am Murali from Bangalore India. We made plating on ziplocks which is made from zamak3 fast from few day I absorbing heavy BLISTERING on ziplocks we tried ultrasonic cleaner with surfolin MZ82, surfolin U 25.
Clean with sulfuric acid 10 ml/lit.

(pictures of unplated parts)

Please give suggestion. Thanking you.

Murali M
NEW PLATER - Bangalore Karnataka India
December 1, 2017

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Q. Sir, I am arivalagan p from trichy india. After nickel chrome plating welded area bubbles problem came in exhaust pipe For last one year, but still now not reduced the problem. Here casting and mild steel join welding area. After nickel chrome plating plating bubbles in vehicle exhaust pipe.

ARIVALAGAN PALANIVEL
sun platers - TRICHY Tamil Nadu, India
October 9, 2019

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Q. We are facing nickel plating bubbles at weld joint area only after heating.and base metal mild steel and we are doing triple nickel layer plating.

Anbu arasu
- Chennai, tamilnadu, India
October 12, 2019

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Q. Thank you for your reply Mr.mark Baker

Problem -- Plating bubble at weld joint

Process -- Soak cleaning + Anodic cleaning + Pickling + anodic cleaning + Acid activation +Semi bright +tri nickel+ bright nickel +chrome activation +chrome

Please note, we have each 2 water rinses in the precleaning stages only.

Part name -- Exhaust pipe

Actually we are welding two part MS & cast iron (CA 40)
And welding material copper coated ms wire.

And we are facing plating bubble at weld joint where MS & CA cast iron weld bead after heating(around 200 °C) at vehicle pre testing.

Before plating we have checked CA 40 material having 12% chrome content and MS having 0% chrome and After welding process Welding bead found 2% chrome content .
And
1.We are facing plating bubble at Cast iron part after heating
2.We are facing plating bubble at MS and Cast iron joint weld bead after heating
3.We are not facing plating bubble at MS part after heating .
Is there any pre cleaning required to solve the plating bubble at weld bead & Cast iron part .

Why plating bubble observed in cast iron and weld bead join area?

Plating bubble observed due to chrome content in the part or poor pre cleaning?

Please suggest..

Anbu arasu [returning]
- Chennai, tamilnadu, India
October 17, 2019

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 Thank you very much ......for your reply

Anbu arasu [returning]
- Chennai , tamilnadu, India

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Effect of Lead Contamination on zamak electroplating

Q. Hi

How high can the lead content of zamak be and still be able to successfully electroplate the zamak?

Am I correct in thinking that lead will cause blistering?

Lead contamination is about 0.3 to 0.5%

Chris McKernan
- Auckland, New Zealand
May 19, 2020