Reply to lteyssed@altern.org, "Anodic bonding glass-titanium"

Hi "lteyssed",

Why some metals bond well and others does not to glass by electrostatic
bonding is an interesting question. I can only give you some thoughts and
references:

The first step in the bonding process is to create an electrostatic force
pulling the materials into intimate contact. If the metal is non-blocking
(providing metal ions to the glass), the charge build-up is too low and
thereby the electrostatic force is too low. This is clearly the case for Ag.
In the final step, anodic oxidation is thought to be necessary to get a
strong and permanent bond. It could be that the metal does not oxidize (like
Pt, but Ti will oxidize) or the properties of the oxide layer are not ideal
(i.e. brittle, poor adherence to one or both parent materials or it is
conductive).

As far as I know (if Im not correct please someone correct me), there are
only three reports about Ti anodic bonding. Two say possible (G. Wallis,
D.I. Pomerantz, J. Appl. Phys., 1969, 40, 3946 and G. Wallis,
Electrocomponent Sci.Techn., 1975, 2, 45.) and one says tried but does not
report successful bonding (W.Y. Lee, F. Sequeda, D. Chapman, J Salem, Appl.
Phys. Let., 1987, 50, 522.).

Good luck,

Ton van Helvoort
Cambridge, UK



>From: 
>Reply-To: mems-talk@memsnet.org
>To: mems-talk@memsnet.org
>Subject: [mems-talk] Anodic bonding glass-titanium
>Date: Fri, 1 Mar 2002 11:06:26 +0100 (CET)
>
>I tried to make anodic bonding between glass and titanium but it was
>unsuccessful.  Have you any idea about why it didn't succeed ?
>
>Thank you in advance.


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