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topic 15914

Problems Electroplating on polycarbonate and PC-ABS

A discussion started in 1999 but continuing through 2020


RFQ: I am currently looking for a plater for nickel plating on polycarbonate, Lexan 143R, would prefer someone in the Southeast if possible. Please contact me if someone is available.

Tommy C [last name deleted for privacy by Editor]
- plastics - Dublin, Georgia
^- Sorry, this RFQ is outdated
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Etching and pre-etching


Q. I am an amateur researcher in the field of electroplating. Would be grateful if you could give me information on the following: What chemicals/other methods can I use for pre etch and etch of --

1. Lexan 143/123 (polycarbonate)
2. Cycoloy C1200 HF (PC-ABS ALLOY)
3. Xenoy1731 (PC-PBT ALLOY)
4. Xenoy1102
5. Lexan 943

Please give me information on the chemicals involved and process chemistry of the electroless plating of metals on the above mentioned engineering thermoplastics


Shobhit Mehrotra
- New Delhi, Delhi, India

2001 2nd Request

Q. Hi,

What is the chemical action of chemicals like NMP or CAS in the pre-etch of PC-ABS? Any chemical equations at hand? What are the other economical methods of plating PC-ABS (CYCOLOY 1200HF)?

Shobhit Mehrotra [returning]
plastics - Gurgaon, Haryana, India


Q. I would like to plate on a plastic containing ABS + polycarbonate (40:60). Please suggest a suitable etchant. Will chromic acid + sulphuric acid work?

Vijaykumar S. Ijeri
- India


A. Dear KUMAR,

Chromic/sulphuric acids etchant will work for ABS/poly carbonate but to increase the adhesion it is better to use pre-etch solution. For polycarbonate it has the following composition:
tri ethanol amine 100 gm/l
ethylene glycol di ethyl ether 80 gm/l
sodium hydroxide 150 gm/l.

Best regards



A. That mixture should do the job. I suggest you run it at about 50 °C and etch for between 15-20 minutes. Make sure you destroy all the hexavalent chromium before going into the plating tanks or it will blister, peel, skip plate and generally fail. I suggest you reduce the chromium to trivalent chromium by washing in sodium metabisulphite for about 10-15 minutes, followed by thorough washing in counterflowed clean water.

trevor crichton
Trevor Crichton
R&D practical scientist
Chesham, Bucks, UK


Q. Can I use some organic based Chrome reducer like Hydroxylamine HCl, Hydrazine Sulphate, Oxalic acid instead of sodium metabisulphite? In your opinion, which is better?

Vijaykumar S. Ijeri [returning]
- India

Swellers for PC

March 8, 2009

Q. We tried several commercial swellers for PC, and adhesion is bad. Can anyone suggest any solvent or mixture of solvents suitable to swell PC ?

We are doing plating on plastics, commonly ABS. We have a new project plating with 100% Polycarbonate. With modified chromosulfuric etch (CrO3 450 g/L + H2SO4 450 g/L), it does not etch/attack the PC. Subsequently, no electroless nickel adhesion. We tried to increase the palladium concentration in the activator, but in vain. We learned that there is some kind of sweller (water soluble solvent) that might dissolve the PC and then makes the PC to be etched by this modified chromosulfuric etch. That's why we need the sweller for pre-treatment on polycarbonate. Thank you for your attention. Thanks.

Simon Lam
plating engineer - Hong Kong, China

Over-etching of PC material

July 17, 2013 -- this entry appended to this thread by editor in lieu of spawning a duplicative thread

Q. We have tried cutting the etch bath after the concentration went to high and we are still seeing over etching in our plastic. The bath is in range on everything. Is there something else I could try to fix over etching.

Josh Dorris
Plating Process Engineer - Farmington, Missouri, USA

July 26, 2013

A. It could be temperature, what with the warm summer weather. Maybe try running the parts in the morning. You can also use less bath time but I suppose you've tried that. What you might be seeing is varying base material. That's pretty common for the type of material you are working with. You may need to write an ECO or allow a temporary deviation and try a less concentrated solution (below approved range) but that would need to be tested. Good luck, you can do it. We're all behind you.

blake kneedler
Blake Kneedler
Feather Hollow Eng. - Stockton, California

Brittleness after plating of PC/ABS

April 23, 2015

Q. I have an application of a chrome plated latch handle for a console. They have designed snap fit features on this part that snap into the pawl. The issue is the parts are cracking and breaking in the field at the snap fits. THere is also a painted version of this that has no issues. I do notice a difference in the brittleness/stiffness of the snap fit areas on the chromed parts. Under a microscope I can see cracking occurring when the snap fit features are flexed that looks to be deeper than the just the chrome thickness. I understand that the etchant attacks the Butadiene, but does it also attack the PC? If so, is that the reason for the brittleness?

Kris Cabanilla
Automotive engineer - Troy, Michigan - USA

Spotty speckles on PC+ABS chromed parts

February 4, 2020

Q. Hello everyone!
We have a PC+ABS moulded part which is electroplated at one of our suppliers. They have the standard electroplating process including copper, nickel and chrome layers.
Recently, we had a very poor yield due to spotty speckles. It might not be the technical term, but this is the the fault name used between ourselves and the supplier. The supplier is saying that the root cause is down to the moulding process and we are saying that the root cause is the plating process.
The speckles are less than 0.1-0.2 mm in size and they are usually in a cluster formation.

Ana Matyas
- Buckingham, UK

February 11, 2020

A. Dear Ana,

If the plater says it must be the moulding and the moulder says it must be the plating, you don't have a root cause, you have an argument.

So some questions for you:

What are "spotty speckles", exactly? From your description it's hard to tell if they're little pits, blisters, discolouration...

Do these problems always appear at the same stage in the plating process or the same region of the parts? Are they genuinely all the same type of defect or have people gotten into the habit of labelling all small defects under the one category?

Has anything in the moulding process changed? Can you document this?

Has anything in the plating process changed? Can your supplier document this?

How are parts packaged and handled as they're moved between you and your supplier?

Jenna Tong
- Gloucestershire, UK

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