I'm searching for a recipe for making electroless nickel plating . So far googling shows that someone perhaps wrote an article on the subject for Live Steam Magazine in 1977 and supposedly it went into the FAQ but I cannot find it there. As I understand it the process is not new nor propietary. I'm aware that Caswell sells a reasonably priced kit, but cheapness is not my sole motivator. I really would like to try it DIY and hope its not imposible nor impractical.
To add to my other message, the Material Safety Data Sheet is required to be provided by US Law. So if you decide to buy some of the stuff from Caswell or Brownell's or any other chemical manufacturer, make sure to ask that they include the MSDS. Don't just ask, "What is in it?" because the usual answer is "It's proprietary". But if you ask for the MSDS they can't refuse.
Perhaps someone here who knows this subject well can chime in, but I believe that if they are classified as hazardous (hell, even sand is now classified as hazardous) , the manufacturer doesn't have a choice. I've never really understood the "proprietary" issue. If I really wanted to know what is in something I can take to a chem lab and have it analyzed. Something every one of their competitors is capable of doing.
There was a lot of research on this in the 1960's. If you have access to the Journal of Research of the National Bureau of Standards during that time period you will find recipes.
I have been there and done that but unfortunately it was back in the
60's and the elapsed time has taken its toll on the memory banks. But AFAIR we had a 2 liter beaker, NiSO4 dissolved in a basic tartrate solution, with hypophosphite near the boiling point. Dip the part in and let it plate. Now the plate is not pure nickel. It is a nickel- phosphorus compound about 93% nickel. We also did this with borate instead of phosphorus which yields a nickle-boron plate.
Can you do this at home? No problem if you can get the chemicals.
Tartrate is a bit unusual for electroless nickel with hypophosphite, citrate or acetate is more usual. Try (all ingredients are in grams per litre):
Nickel Sulphate NiSO4.6H2O - 25 g Sodium hypophosphite NaH2PO2.H20 - 23 g Sodium acetate NaC2H3O2 - 9 g a touch of lead helps (dip a small bit of lead in the solution for 60 seconds, that's plenty)
85 C
ITYM sodium borohydride.
Nickel sulphate 12 or nickel chloride 9 sodium potassium tartrate (rochelle salt) 65 sodium hydroxide 40 sodium borohydride 1 a bit of lead again.
92 C
Can all be bought online in the UK, except maybe the lead (I haven't tried). I don't know about elsewhere.
The pros "sensitise and catalyse" or "catalyze and activate" the surface first, which is a whole other story, usually involving palladium chloride. I don't know whether Caswell kits do, but I doubt it.
The Metals Handbook, Vol 2, 8th edition contains a number of recipes and devotes several pages to the process. The subject is complicated and no doubt expensive to experiment with provided you can find the rather unusual chemicals required.
That is a displacement method, the copper replaces some of the iron. You can do something similar with tin replacing copper, useful for electronic circuits.
Electroless nickel is not a displacement process however, it is an autocatalytic process - the solution wants to deposit the nickel, but it needs a catalyst (a catalyst is a substance that changes the rate of a reaction without itself being changed in the reaction) to do so at any reasonable rate.
The surface of a layer of freshly deposited nickel will act as a catalyst, which means a layer will grow thicker, hence the "auto" part of "autocatalytic" - but to start a layer growing requires some catalytic activity on the material to be plated.
Some material surfaces already have enough catalytic property, and some do not. That's why:
and you may have to address that issue to get reliably good results.
There are also additives that can improve the deposit, maintain the solution, and/or make the process work better, but that again is another story, and you'll need to read a book or two for that. And practice too, it's an art as well as a science.
"Modern Electroplating" 4th edition by M Schlesinger ISBN 0-471-16824-6 is a good place to start. See Chapter 18.
Use a glass or ceramic container. Use deionised water. Dissolve the hypophosphite seperately in a bit of water and add it last, after the other stuff has dissolved, shortly before use. The mixed solution does not have an indefinite life - it's life can be quite short, depending on the impurities in the chemicals, the surface of the container, etc.
Use gloves goggles respirator.
Nickel, especially nickel salts, is a bit toxic to humans as in drinking it or splashing it around, and some people are allergic to it. People can become sensitised to it too.
Nickel salts are also a known human carcinogen targetting mostly the lungs, especially the dust or fumes. Avoid. It's one reason smoking tobacco causes lung cancer BTW.
Nickel salts aren't too good for the environment either. In the US you have to report the disposal of more than one pound of nickel compounds per year. To dispose of small quantities of unwanted or used solution, add 10% sodium sulphide solution until no more black precipitate forms, filter or decant, put the precipitate in the bin for landfill, and pour the remaining liquid down the drain with a bit of bleach. A recycler may take larger quantities.
Sodium hypophosphite is a strong reducing agent and dangerous mostly for that reason - it "burns". Can also give off dangerous fumes when hot, and I'm told it can explode if heated and confined.
Sodium acetate is mildly irritating, but otherwise mostly harmless.
Don't mix any chemicals if you don't know what will happen.
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