Letter 37569

Can sulfuric acid be used to remove nickel plating from aluminum?  

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Hi,
I am an engineering student from Malaysia. I am conducting a research on: can sulfuric acid be use in etching to remove a nickel plated aluminum disk? I would like to remove the nickel but not the aluminum from the disk.
1. what is the concentration of the sulfuric acid for etching? ( is it 30% )
2. do I need to mix the acid with water?
3. is the method the same as anode and cathode?
4. how to calculate the time for the etching process?
5. what is the suitable container to use for etching?

can anyone have the procedure or idea to conduct the experiment above?

hope to get some help..
thanks in advance.

Lee Chee Hun
student - Malaysia

Nickel can be stripped from aluminium using the Laybere solution; this a mixture of 3 parts of conc sulphuric acid to 2 parts of water. It is used at room temperature with an applied anodic current of about 40A/ft**2. Your container will depend on the size of your parts, but I see nothing wrong with a glass beaker if it is of the correct size. If you need something bigger, use a PVC, polypropylene or rubber lined steel tank. As far as the processing time is concerned - it all depends on how much nickel you have to remove and what the temperature is. Now that you have been told what to do for your project, go and do some experiments for yourself, but don't forget to give due reference to the sources of your information as it would be most unethical to claim the credit yourself.....

Trevor Crichton R&D practical scientist - UK

I doubt if it will work. It will also depend on what the aluminum alloy is.
Look at concentrated nitric acid. One notch below red fuming. Regular nitric that most people would use commercially has too much water in it. The part has to be absolutely dry when you put it into the acid. Note that it will slowly absorb water from the air and you will at some point have etched parts.

James Watts
- Navarre, Florida

Hi,

Pls do help me out with my experiment, as the dateline is next week. I have no idea whether sulfuric acid can be use to etch ( remove ) the nickel plated aluminum disk. I only want to remove the nickel not aluminum. Currently, I am using aluminum potassium sulphate to etch ( remove ) the nickel.

thank you.

Lee Chee Hun
- Malaysia

Thank you Trevor Crichton & James Watts.

Dear Trevor Crichton,
I will definitely acknowledge the ideas given by you in my project. will sulfuric acid perform better that aluminium potassium sulphate to etch the nickel plated aluminium disk?the area that I would like to remove is about 1 cm x 1 cm only. i can use the Laybere solution as a guideline?

Mr James Watts,
Based on your respond, do you mean that sulfuric acid will not be able to etch (remove)the nickel plated aluminium disk? and nitric acid will be a better solution?
'One notch below red fuming' I don't understand this statement. can you explained further.

hope to hear from both of you soon.thanks,

Lee Chee Hun
- Malaysia

Laybere solution has been well known for many years, so there is no reason why it cant be used as a benchmark. I think you will find the sulphuric acid bath will react faster than aluminium potassium sulphate. Be careful of the sulphuric acid as it is very corrosive.

Trevor Crichton R&D practical scientist - UK

My company regularly uses a 50% (vol) solution of Nitric acid, and DI water to remove nickel from aluminum. This solution will hardly attack the AL substrate, and works quite well.

Marc Green anodizer - Boise, Idaho

OK, my head was somewhere other than firmly attached to the neck. The procedure that I talked about was for removing EN from steel. My bad.

In another letter, an author talked about using 12% sulfuric acid with peroxide for removal of EN. Do not remember the substrate.

James Watts
- Navarre, Florida

Hi,

thanks so much for the positive responds.

As the dateline had been extended, I hope to try out the two experiments using sulphuric acid and nitric acid.

I am trying to source for a ampere meter. ( Do I need it? )
this is how i plan to conduct the experiment:
1. i will conduct it in a fume cupboard.
2. pour 150 mL of H2SO4 to 100 mL of DI water in a bicker.
3. after mixing it,will place a dummy disk in the bicker.
4. the Al disk ( 95 mm diameter ) will be placed inside the bicker.
5. the current is about 9 V. Anode will be clip to the Al disk, while Cathode will be connected to the dummy disk.
6. etching time still unknown... ( can it be calculated/ measure ? )

Pls do correct me if my procedure is wrong.
how will the ampere meter come to good use? how will it function?
any other better suggestions?

thanking all of you in advance.

Lee Chee Hun
- Malaysia

Ed. note: Ampere-hour meters are available from all suppliers of rectifiers and power supplies. Several are listed in our equipment directory.

James, the sulphuric acid/peroxide mix is pretty potent and will take off most metals - I have used a similar formulation for dissolving both nickel and copper, but it will chew up any metal substrates of you're not careful!

Trevor Crichton R&D practical scientist - UK

Hi,

Any suggestions / ideas regarding to the procedure that I am going to use? is the method correct? as I hope it is safe to conduct it.

pls let me know, thanks again.

Lee Chee Hun
- Malaysia

You can use electrolytic etching-this process is much safer than H2SO4.Slightly acidified nickel sulphate solution can be used as electrolyte,object =anode,platinized titanium or stainless steel=cathode.

Good luck!

Goran Budija
- Zagreb, Croatia

You will need an ammeter to tell you the amount of current being passed. You will also need an accurate clock to tell you the time spent; I suggest a stopwatch. Your process looks basically sound, but I suggest you check with your supervisor before doing it - he knows your abilities and the abilities of your classmates and the equipment. Furthermore, he is responsible for you!

Trevor Crichton R&D practical scientist - UK

Hi,

Thanks, I had tried out the experiment with sulphuric acid, its a bit dangerous as sulphur gas was released during the etching process. will nitric acid be the same as well?
additionally, I would like to add a system (timer) that can cut off the current once the etching process is finished.
can it be done? with this, I will try out on different surface size to etch, so i can set approximately the time needed to stop the current once the process is finished.
but I am concern that the aluminum potassium sulphate which I am currently still using will degrade after 2 rounds of etching. the time set for the 1st round should be faster compared to the 2nd round,right? will it be the same as well for sulphuric acid?

thanks again for replying.

Lee Chee Hun
- Malaysia

No, sulphuric acid is not the dangerous part! The dangerous part is conducting experiments other than under a lab hood, or other than while wearing the correct PPE experiment, or without proper training and/or supervision. Asking a stranger over the internet, who you don't know, and who doesn't know you or your facility or your training level, about the safety of a proposed experiment is dangerous. As Mr. Crichton noted, your supervisor is the one to ask.

Ted Mooney, P.E.  finishing.com Brick, New Jersey

 

If you want to remove the nickel from hard drive disks you cut the disks up into 1/4 inch strips and soak it in hlc or muriatic acid this will dissolve all the aluminum base metal and all you are left with is the nickel platinum cobalt alloy thin film. I do this all the time and sell the foil on ebay as a platinum alloy. there is a fast reaction at first it takes about a week for me to dissolve 60 disks at once I hope this helps.

William Thompson
- Watson Sask, Canada

you cold use household bleach, it works on the disk

theodorus schuurbiers
- curacao iland in the caribean

Hello all,

I am a Belgian collector of antique guns and currently trying to remove an old damaged nickel plating (could be nickel/chrome)from a steel gun frame.
I tried electrolysis with a solution of about 30% Sulfuric acid (I use battery acid)and distillated water. Temperature
about 20°Celsius, current is supplied by a car battery charger.

Well, it doesn't work at all. The acid attacks the steel and destructs my anode, but it has no effect at all on the nickel plating.
The gun is a Colt 1849 Pocket made in the late 1850's but I doubt the plating is original factory work.
I usually remove rust from steel parts using a solution of
abt 30% of Chlorhydric acid and water in the very same home-made electrolysis installation. The solution removes all the rust and does not affect the steel in any way.
Yet chlorhydric acid doesn't work on nickel plating either.

An US correspondent told me about a good and effective chemical produced by Brownells , but it seems like that company is not allowed to export the product.
So if anyone can provide a better solution, I'll be very pleased to read about it.

Thanks in advance,

Marcel Cansse
- Knokke, Belgium

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