Hi Peter,
Significant Nickel oxide is formed within minutes after plating and it keeps
growing. It is not an adequate substrate for electroplating and you need to
remove it prior to plating with Au. You could try with HCl (HCl(30%): water,
1: 1, at room temperature). As you have 10 microns of Ni you can keep it
while stirring for 1 minute (if your sample was left for long time exposed
to airand humidity it may take longer). Shortly upon oxide removal and DI
water rinse (all at room temperature) you should start plating gold,
otherwise you will have the oxide formed again.

Igor Kadija
ECSI FIBRotools
www.fibrotools.com
201-670-83977

----- Original Message -----
From: "P.E.M. Kuijpers" 
To: 
Sent: Monday, March 12, 2007 9:27 AM
Subject: [mems-talk] Plating Au to a Ni seed layer


> Hi all,
>
> I want to electroplate a 3µm thick Au layer onto a 10µm thick Ni
layer.
> This Ni layer was also electroplated.
> What kind of pre-treatment should I use, to obtain a good adhesion between
> the Au and Ni layer??
>