Hello there, Thanks a lot for Igor and Peter's reply to my previous
question. May I also repeat my story here?

A gold finish is required to my nickel part (electroplated nickel). The
problem is that electroless gold won't stick well to the nickel
surface(lift problem). I tried the acid dip from Igor's advice with
various time scale, but it improved very little in term of adhesion. I
also tried woods nickel strike to put on a fresh nickel on the 'old'
nickel surface. The fresh nickel stick very well on the 'old' surface.
However, the electroless gold can still be easily peeled off from the
woods nickel. I am wondering whether electroless gold can only be used
together with electroless nickel (with crucial role of phosphorous).
Would you please help me if you can.

Many thanks!

James

-----Original Message-----
From: mems-talk-bounces@memsnet.org
[mailto:mems-talk-bounces@memsnet.org] On Behalf Of IGOR KADIJA
Sent: 24 May 2007 00:56
To: General MEMS discussion
Subject: Re: [mems-talk] Activation of 'old' nickel surface

The 5% HCl is rather week for the purpose. I would expose "old" Ni at
least
1 min to 15% HCl (50/50, H2O/conc HCl) and then proceed with longer time
on
a trial and error basis if needed. However, you should have at least
several
hundred nanometers of Ni under the Ni oxide/old Ni, to maintain Ni
continuity.  Remember, after removing oxide you need to transfer for
plating
immdiately. Typically, significant Ni oxide grows back within few
minutes.
Igor Kadija
www.fibrotools.com