Peter Fairbrother wrote:
siliconmike wrote:
I'd like to learn how to do electrolytic nickel and gold plating on
copper sheets. Any web resources/links etc. ? I tried to search on
google but almost all results were commercial companies.
My exact application is to
1. edm wire cut copper foil (100 microns) - about 10mm x 10mm piece
2. clean off the corrosion on the edges due to wire cut process
3. nickel plate and make total thickness 130 microns
4. gold plate about 2 microns.
(I'm not sure whether I need to do step 2).
You do, but it's just part of the process and nothing special. You'll
probably have to polish and you definitely have to clean the copper
before
nickel plating anyway.
Nickel plating is not too difficult, but good gold plating requires
using
cyanide - could you send off for the gold plating? Unless you are
doing a
lot, it will be easier. Much easier.
My volume is 2000 Nos. of 100 micron (10mm x 10mm) square article per
month.
Mind, the gold plating shop will usually also do better polishing and
nickel
plating than you can, as they have the experience and the large
volume tanks
(volume makes a difference, maybe it shouldn't but it definitely
does).
I tried to get it done locally (Ahmedabad, India), but somehow I could
not get professional quality plating here. The article is so delicate
(100 micron) that the plating people would bend/deform it due to bad
handling.
No, I need to know more about what you want to do. First impression,
for a
gold plated copper foil square, get it done rather than do it
yourself. You
can probably buy gold plated copper foil anyway. But I expect it's a
bit
more complex than that ...
This article is used as a leaf-spring with a mild spring action (nickel
induced) to make a weak electrical contact with a moving gold plated
part
What is the final finish required? Rough, dull, matt, satin, bright,
mirror?
'Cos that's where you decide where to start. Ooops, I forgot the very
first
question, how many?
Whatever finish is good for a good electrical contact. Or maybe finish
is not too important ? I've never thought of the finish part. Qty=2000
per mo.
I can do (and have done) nickel, NiCo, NiCu, NiFe, NiCoFe*,
NiCrCoFe*,
copper, copper/tin and copper/nickel electroforming, and all those
[1] plus
iron [2], tin and some [3] silver plating, but not gold - this may be
partly
because it's almost impossible to get cyanide here in the UK. However
if I
really wanted to I probably could get cyanide, so it may also be
partly
because I simply don't want to work with cyanide, and I'm just using
the
difficulty as an excuse ... I don't know how hard it is to get
cyanide in
the US (where I presume you are located).
maybe If I can do nickel myself, then the piece would become hard
enough, so that I can get gold done in a shop. That way even if they
slightly mis-handle the article, it won't get damaged easily.
here we go -
clean, etch in 30% room temperature sulphuric acid for 3 minutes at
3
A/Dm^2 for 2-3 minutes anodic followed by 6 minutes cathodic. It is
advisable to use two tanks, one for the anodic and one for the
cathodic
cleaning, to prevent Cr and Fe buildup.
Can you please explain this in detail. I cant understand most terms
like "anodic cleaning" etc.. I'm more of an electronics guy than a
chemical guy. But I guess it shouldn't be too hard to home plate
nickel.
Plate in:
250 g/l nickel sulphate
commercial sulphuric acid 25 ml/l
- weight equivalent 50 g/l
16-22 A/dm^2, 30-40 C, for 5-10 minutes. sg 1.160. One nickel anode,
remaining anodes chemical lead.
It that the kind of advice you are looking for?
Sure, but in English. (Just kidding). Can you explain it in simple
steps without figures. Like: "Take a beaker and mix nickel sulphate and
whatever..". I'll find out what the above figures mean from a chemistry
hand book.
Thanks a lot
Mike
--
Peter Fairbrother
|