Rudy:
Electrons will move from Cathode to Anode. The "holes"
(atoms missing electrons) move in the opposite direction. The solution
has positive ion charge metal atoms that are attracted to the cathode
and turn into solid metal by absorbing electrons from the cathode.and
thus plating the base metal attached to the cathode. See
http://www.finishing.com/faqs/howworks.html for a longer electrical
descriptive account.
Regards,
Ramon
________________________________
From: R Sedlak [mailto:[log in to unmask]]
Sent: Thursday, May 25, 2006 12:55 PM
To: TechNet E-Mail Forum; Dehoyos, Ramon
Subject: Re: [TN] electroless gold thickness'
Ramon:
In the world I inhabit, the work being plated is nominally defined as
being the cathode....
At this site, the ions in solution, which are positively charged, are
converted to metal by adding electrons...
This may be in violation of other conventions, or not, I am not sure,
but in the world of electroplating, the cathode receives electrons
pumped from the anode, and feeds them to the positively charged ions, to
convert them...
I do not try to understand these things, I just report the news...
Have a good weekend.
Rudy Sedlak
"Dehoyos, Ramon" <[log in to unmask]> wrote:
The electron source is the cathode (negative polarity,
excess electrons) and the receiving end is the anode ( positive
polarity, missing electrons).
Ramon
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of R Sedlak
Sent: Wednesday, May 24, 2006 6:26 PM
To: [log in to unmask]
Subject: Re: [TN] electroless gold thickness'
Cheryl:
Plating from solutions involves transfering electrons to ions
floating
in solution, converting them to metals, hopefully on the surface
we
want.
There are three kinds of plating from solutions...
immersion plating
electroless plating
electrolytic plating
The three different methods differ in the source of the
electrons...
In immersion plating, some of the substrate dissolves, releasing
electrons, which cause the metal in solution to plate out. This
kind
of plating is self-limiting, when the substrate material gets
covered,
plating stops. This is why you cannot get gold over about 0.25
micron
in IMMERSION gold.
In electroless plating, another chemical in solution donates
electrons
to the metal ions in solution, causing them to plate out. There
is
theoretically no limit to the thickness you can achieve using
electroless plating... thus achieving 0.5 micron gold can be
done with
ELECTROLESS gold.
And for the record, the rectifier, also known as the "electron
pump",
pumps electrons from the anode to the cathode in electrolytic
plating.
Rudy Sedlak
RD Chemical Company
Cheryl Johnson wrote: I believe I have
seen this somewhere, and have tried searching the archives, but
am
having trouble finding it.
Does anyone know of any processes for electroless gold that can
obtain >
.5 micron thickness (without needing bus bars?) Or any way to
get > .5
micron gold on a flex without bus bars?
Thank you!
Sincerely,
-----------------------------------
Cheryl Johnson, C.I.D.+
Manager
ExcelStor US Office, Engineering Services
Email: [log in to unmask]
Tel: (303) 684-7291
Fax: (303) 684-7268
Mobile: (303) 809-5815
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