Reaction of ammonia solution in Nickel electroplating.
Hafel
used as the pH adjuster in the nickel electroplating. And the benefit
of using ammonia as pH adjuster compare with CaCO3.
Thanks for anyone who can give the response.
Salmon Egg
1181628901.9...@i38g2000prf.googlegroups.com, "Hafel"
<AnGh...@gmail.com> wrote:
I am not a professional chemist. Ammonia will complex with silver and
copper. Why would forming a complex with nickel, if that actually happens,
be a surprise?
--
Iraq: About three Virginia Techs a month
beav
it depends what kind of Ni solution you're talking about.
for instance, NH4(OH) in a Watt's bath is worsse than no help. if you
wanted to adjust pH in a Watt's bath, say after too generous a H2SO4
addtiion, one would add NICO3.
what kind of bath do you have?
number6
> On Mon, 11 Jun 2007 23:15:01 -0700, Hafel <AnGhf...@gmail.com> wrote:
> >Hi, I m interested to know about the reaction of ammonia (aq) which
> >used as the pH adjuster in the nickel electroplating. And the benefit
> >of using ammonia as pH adjuster compare with CaCO3.
> >Thanks for anyone who can give the response.
>
> it depends what kind of Ni solution you're talking about.
>
> wanted to adjust pH in a Watt's bath, say after too generous a H2SO4
> addtiion, one would add NICO3.
>
> what kind of bath do you have?
So true ... I spent hours back in my youth finding a chemical or
process to remove ammonia from a Nickel bath ... so as to pass the
brittleness spec ... btw ... kitty litter worked ...
Hafel
> it depends what kind of Ni solution you're talking about.
>
> for instance, NH4(OH) in a Watt's bath is worsse than no help. if you
> wanted to adjust pH in a Watt's bath, say after too generous a H2SO4
> addtiion, one would add NICO3.
>
> what kind of bath do you have?
i use the Nickel sulfate bath. To plate the Nickel out, i choose the
ammonia as the pH adjuster, and if i use the CaCO3/NiCO3 to adjust pH,
i have to filter the white solid out, it is very inconvenience for the
nickel electroplating as the process is sensitive to the change of
pH ,and only able to stand with small range change. So , i would like
to know if the ammonia was used,then what is its effect to the bath
except of ph change? i mean anyone knows about the reaction of ammonia
in the nickel electroplating?
Besides, Mr Beav, may i know why if i use Watt 's bath, the ammonia is
not suitable for use?
number6
If you read my post you would see the effect of ammonia on the
brittleness of the coating obtained ...
hanson
news:1181672155.3...@i38g2000prf.googlegroups.com...
Hafel <AnGhf...@gmail.com> wrote:
>> > I m interested to know about the reaction of ammonia
>> > (aq) which used as the pH adjuster in the nickel electroplating.
>> > And the benefit of using ammonia as pH adjuster
>> > compare with CaCO3.
>>
>> it depends what kind of Ni solution you're talking about. For
>> instance, NH4(OH) in a Watt's bath is worse than no help. if you
>> wanted to adjust pH in a Watt's bath, say after too generous a
>
"number6"
> So true ... I spent hours back in my youth finding a chemical or
> process to remove ammonia from a Nickel bath ... so as to pass
> the brittleness spec ... btw ... kitty litter worked ...
>
== True, in certain Ni-baths NH3/NH4+ or RCN or anything N
containing will increase the hardness of the Ni plate and make
it brittle (while it also increases the brightness of the Ni-plate).
http://groups.google.com/group/sci.chem/msg/6cb150ca7fd4bd04
>
== IIRC our in my Finishing Divison they added H2O2 or K2SO5
aka peroxides to oxidize the Ammonia into harmless N2 gas.
== "kitty litter worked"... = Vermiculite or Montmorillonite clays.
if true, then it is interesting to note that the clays do absorb NH4
compounds in the baths. The idea though is not too far fetched
and actually quite ingenious... if kitty litter absorbs the NH3 smell
from the cat piss the why shouldn't it work in the plating bath. \
Inconvenience may be that filtration is required, but then most
large tanks are filter anyway.
== AFA CaCO3 is concerned, all it does is to reduce the acidity
by dropping out a sparingly soluble Gypsum sludge, CaSO4 aq.
that has to be filtered out, but it will not affect the NH4 content.
NiCO3 types are the way to go, like BEAV said.
== ....all that aside here's a funny story of how sensitive a Nickle bath
can be to all sorts of contamination... See Vignette in:
http://groups.google.com/group/sci.chem/msg/1447cc78a718a0d5
where the dunker took a shit into a 150'00 gallon tank... ahahaha...
Have fun, guys... ahahaha.... ahahahanson
number6
> "number6" <snumb...@aol.com> wrote in message
> == "kitty litter worked"... = Vermiculite or Montmorillonite clays.
> if true, then it is interesting to note that the clays do absorb NH4
> compounds in the baths. The idea though is not too far fetched
> and actually quite ingenious... if kitty litter absorbs the NH3 smell
> from the cat piss the why shouldn't it work in the plating bath. \
> Inconvenience may be that filtration is required, but then most
> large tanks are filter anyway.
Actually the lead time to get a sample of the clay that I found in a
reference was a couple of weeks ... but another reference showed that
that company sold it to the kitty litter market ... so a dollar and a
ride to the supermarket cut the experimental wait down to nothing ...
chalked up another hero medal on my chest ... I repeat this a lot as
an example of how open eyes and common sense can go a long way in
solving a problem and get one recognition ...
beav
there is an Nickel ammonium sulfate plating bath, but its not
generally used, because the NiSO4 watts style bath is so simple, has a
wide acceptable current density range and produces a bright (or
semibright) tough plate..
presuming you are using a barrel plating method, the bath is pretty
tolerant of solids,too. i used to plate Ni over brass over Al. the
Al parts that would invariably fall into the tank would dissolve
eventually and form Al2(SO4)3 sludge. when i started working there
the sludge had nearly filled the tank, yet the parts plated fine.
when you add NiCO3, you just don't "throw it in." you make small
additions by putting a reasonable amount of NiCO3 in a pail, adding
some plating solution and mixing it IN THE PAIL. that mixture gets
added to the tank and then the tank is well mixed. then remeasure
your pH. repeat as necessary.
if you are getting white precipitate, you may have high Al levels,
too, or REALLY high H3BO3.
NH4(OH) is a bad choice. so is NaOH or KOH. you should adjust pH
with either NiCO3 or H2SO4 ONLY. that's it.
when's the last time you filtered the bath? rack plating needs
constant filtration, barrel plating could use constant C filtration,
not only to get out floating solids, but to sop up organic brightener
residue.
how long have you been using NH4(OH)? the only experience that i've
had with an ammonia contaminated (and yours is, if you been adding
NH3) is to throw out the solution.
i never tried kitty litter. that's a great idea. with Ni at $10.00/#
i'd try anything. i attempted to make the solution as basic as
possible with Ca(OH)2 then boiling the solution to drive off teh
ammonia, but NH3 is such a powerful ligand with Ni.... i never got an
acceptable plate with the solution after all that work.
basically your tank is screwed, if you used ammonia in a Watts sulfate
bath.
>