Q&As on Nickel Plating of Aluminum

I can't comment on the adhesion values and other characteristics of the nickel plating achieved with Ahmad's method, but I can confirm that he is not the only person to achieve electroless nickel plating on aluminum with this general method.

Luck & Regards,

A. Hi,

How about this way? First, You have to anodize Aluminium which you would like to use. And then do Electroless Ni Plating. I'm not sure of Adhesion Power of Nickel layer plated on Anodized surface.

Good Luck

A. How about just anodizing to look like nickel? Anodizing hardens the surface of aluminum and prevents oxide look. Also you can anodize any color you want.

A. Hi. Aluminum can be electroplated onto, and in fact the overwhelming majority of chrome plated auto wheels today are cast aluminum. The aluminum must be zincated first, then either cyanide copper plated or electroless nickel plated before going on to the final decorative finish. Although not every jobshop is set up to plate aluminum, or experienced in it, it is not a rarity either.

Still, I tend to agree with Ronald that anodizing and dyeing would be more straightforward than plating.

A. Hi Gunter. There is probably no plating operation (or any process) that "is not a problem at all" :-)

As for those who say it is difficult, yes, somewhat: Surely, if your question were, "is brass or steel or zinc diecast easier to plate than aluminum", the answer would be yes. If the question were "which substrate is easiest to plate", the answer would probably be brass.

On the other hand, aluminum is certainly successfully plated. For example, most fancy nickel-chrome plated wheels are aluminum (and pressure castings, no less -- much more difficult than pure aluminum).

Aluminum instantly oxidizes after pretreatment so that an immersion plating process with zincate is necessary before plating, and while this is certainly widely done, yes, it is more problematic and somewhat less reliable than plating onto other metals which do not require an immersion plating layer. Good luck.

A. Most experienced platers get to be good at it or they get out of the business. Can a beginner do good work? Not many, as it has a big learning curve. The zincating step is the hard one as there is virtually no visual indication of a bad zincate step vs. a good one. It is very subtle.

A. Aluminium is quite easy to electroplate as long as it is the right grade. The process follows a zincate route and this should be supplied by a reputable supply house. This supply house should be able to provide all the necessary chemistry for the zincating process and any subsequent metal deposition. Details of the correct grade of aluminium can be quite long and laborious, so it is best to consult a suitable book on the subject, or talk to one of the aluminium trade development associations.

A. If the process cycle is set up right, I feel it is easier to teach a beginner to plate on aluminum then it is to "unlearn" some old timer that thinks he knows it all and takes liberal short cuts to the finish line. I have far less trouble and much higher quality yield servicing clients who have the correct process cycle than I do trying to service a shop that has built in reasons to fail. And, Oh, I first set up an aluminum plating line at age 17, now I am 71, that is one year experience 54 times ! Set it up right - it is easy !

A. Yes almost all alloys of aluminum can be nickel electroplated. You need a good pre-cleaning process sequence that includes non-silicate base alkaline cleaner, nitric+hydrofloric acid & zincating solution. There are many zincating solutions available in the market for this.

A. Hi, Andy. The zincate film is very very thin (it's only an immersion deposit) and very subject to dissolution. My personal understanding has been that nickel plating baths will dissolve it.

This is just an explanation of the difficulty; it is not meant to discourage experimentation or to imply that other approaches are impossible -- in fact, in letter 27627, "Copper-nickel plating peels off aluminum" Trevor Crichton and Jonathan Timms claim that nickel electroplating is better than copper electroplating. Good luck.

Regards,

A. To plate over Aluminum is much different from other material, especially at the cleaning step of whole process, need to take care what kind of cleaner, how long the Aluminum should be cleaned, etc.

We've been successful on this and our plated Aluminum is in commercial run; it can save a lot of material cost over Zinc, and strength is stronger on some parts .

A. Well, Sirs,

We will kindly recommend to please check the silicon percentage before determining any of composition/ process, as the cleaners will change according to the silicon percentage (in particular aluminium die castings).

In some cases you can visually check the job and get it okay, but certain time period after plating it piles up, or blisters occur.

Hope it will work well, otherwise feel free to revert back, and it's our pleasure to share technical aspects.

Regards,

A. Hi, Sammy.

Anodizing is an insulator whereas electroplating is an electrolytic process which must be applied on a conductive surface, so you must have the anodizing stripped first. But yes, the aluminum can then be nickel-chrome plated. Not every shop can plate on aluminum because it requires a process called zincating, and then an alkaline electroless nickel strike before the nickel and chrome plating though. Good luck.

Regards,

A. Hi, Al. Clean, etch, desmut, zincate, nitric strip, zincate (with rinses in between). We already had threads where your question was answered -- but please expand upon it if you feel that it wasn't fully answered yet. I'd suggest that you talk to your nickel sulphamate plating process supplier about setting up the pretreatment steps. Good luck.

Regards,

Q. Hi Ted,

Thank you for the reply. I have spoken to our current supplier. The recommendation he made was similar to yours, a pre-treatment line. However with a stand alone activation line I might be in trouble with floor plan. We have an existing Ni line now, mainly plating Cu (pure), and it would be much easier if there was a new single or maybe tanks that can be added to the existing line to activate aluminum for Ni plating. How many tanks the pre-treatment normally consist for the application of zincate film, thank you

A. You will need a cleaning tank for aluminum. You probably need an alkaline etch. You probably need a desmut tank, then the zincate tank, and an HNO3 tank to strip the zincate before reapplying it. You'll need rinse tanks after each of those steps. Good luck.

A. Hi Neelanjana.

You usually cannot electroplate directly onto aluminum because it instantly forms an oxidized skin; instead you must first do an immersion plating of zinc onto the aluminum from a highly alkaline tank containing a high concentration of zincate (Zn(OH)₄^-2. It is good practice to then strip this deposit away in nitric acid and re-apply it before commencing electroplating or electroless nickel plating. Complete details are available in The Surface Treatment and Finishing of Aluminum and its Alloys.

Regards,

A. My guess is that the oxides and corrosion products on the bars are not uniform. Since you cannot plate thru most oxides, I would try a better prep cycle or even mechanical cleaning before chemical.

Another possible problem is the bars might be extruded. It is not uncommon to have lubricant spots on or burned into the aluminum leaving spots that are unplatable.
These are nasty to get around. You can frequently spot this with a careful incoming inspection.

A. It may be that you have set up a localized electrochemical cell between the tack and the aluminum being plated.

What is the tack material? If the aluminum is anodic to the tack material then there will be no zincate coating near the tack. A different tack material may solve the problem. Another possible fix is to put a low, cathodic voltage on the part, a sort of cathodic protection. If the tank is unlined steel, then the tank can be the anode.

A. Hi Manoj. Virtually every step in the process is debatable or has alternative approaches, but I'd say that a rather typical step-by-step is: Soak Clean - Etch - Desmut - Zincate - Strip in HNO3 - Re-zincate - Alkaline Electroless Nickel Strike - Nickel Plate. Good rinsing is required between each step. Good luck.

Public forums, with their short & to-the-point answers are excellent for highly specific problems; but plating books, with their chapters of information and explanation, are far more appropriate to general introductions to technologies; the idea that anyone can compress a broad technology and decades of experience into a two-paragraph answer is a bit silly. Please describe your situation and tell us why you ask. Thanks!

Regards,

A. Hi cousin Safwan. It is certainly possible to do nickel plating on many metals, probably most metals. Please explain why you want to know the answer to this question and what you are actually trying to do though. Otherwise, readers would have dozens of reservations and ifs-ands-&-buts that would take 20 pages to enunciate. For example, surely you don't want a treatise about why you can't do traditional aqueous plating onto sodium? Thanks :-)

Regards,

Q. Respected Sir,
It's my assignment to find out that can we do nickel plating on Au, W, Ag, Al, Cu, alkali and alkaline earth metals.

A. Hi again. You can do nickel plating on Au, W, Ag, Al, Cu and a number of other metals. Not always following the same sequence, and not with equal ease ... but you can nickel plate them.

Which of the alkali and alkaline earth metals do you feel that you can form into metal pieces, and which would not be so reactive as to be impossible to place them into a water-based bath for nickel electroplating? You can probably nickel electroplate those.

It may also be possible to apply a nickel coating by other means than aqueous electroplating from a nickel salt -- so your answer may depend on exactly what you mean by "nickel plating". In one context "nickel plating" may be an abbreviation or slang for "conventional nickel electroplating from an aqueous bath" whereas in another context it may mean getting a nickel surface onto an object regardless of application method, and might include methods such as chemical vapor deposition, physical vapor deposition, or cladding. Good luck.

Regards,

Q. Can you please explain chemical vapour deposition for Na and K.

A. Hi again cousin. Can you point to a sodium or potassium object that has been CVD nickel plated, or give us the evidence of why you think it should be possible?

Although you say that the reason you want to know is because it is your "assignment", that still leaves things so completely abstract that your question has garnered zero reader interest despite your 3 postings. And between all three postings, you haven't yet invested even a total of 50 words on your own behalf :-(

Readers enjoy participating in problem solving, but no one is attracted to doing research for people on vague topics with no hypothesis, and no way of achieving any sense of accomplishment. Charles Darwin himself said that such efforts are like wasting your life going down into a gravel pit every day and sorting the pebbles by color and size with no greater objective :-)

So what are you trying to do? What is your hypothesis or intent? Why? Thanks!

I'm not trying to give you a hard time cousin, I'm just relating 25 years of experience here in why some questions draw enthusiastic responses and start a lively dialog, while others like yours draw utterly no interest from anybody anywhere despite being viewed by thousands of people :-(

Regards,

A. Hi T.K.,

Nickel oxide

A thin coating could probably be achieved by nickel electroplating followed by exposure to heated oxygen. Any particular thickness, purity, characterization, or specific purpose for the coating?

Regards,

A. Hi Andy. High strength aluminum 2xxx and 7xxx is generally more difficult to reliably anodize or electroplate than 6xxx alloys. Not all plating shops can electroplate onto aluminum; it's best to ask the shop if they do so. As you see on this thread, you need a cleaning cycle specific to aluminum, and then your zincate and nitric strip tanks.

Regards,

A. Hello Andy,
6063 alloy is really beautiful to work for anodising. It has properties which can give good finish. for better machining strength or hardness you can go for 6061, but my experience is that it does not give good aesthetics compared to 6063.
Hope it helps.

Regards,