Alumina Substrate bonding to gold fingers of a connector

[marshell]

Hello,

We are using a card edge type of connector, with ni\au on the contact surfaces. We are plugging a ceramic board with gold fingers into it. When we remove the ceramic board the pins of the connector are coming out with it. Is there some sort of chemical bond that can take place between these to materials? We have tried normal FR boards, and have not had the problem, only with the ceramic.

Your thoughts and help on this are appreciated.

Thank you.

 

[Compositepro]

I seems you may be right (from what you say in the title) that the problem is bonding to the Alumina. So your next step would be to test the bond strength of the contact to alumina compared to FR(4?).

 

[unclesyd]

I would search the NASA Data Bases as I recall seeing a paper on you problem.

 

[tomwalz]

You can braze them. It is called brazing because of the bond formed but there are many temperature options. Maybe more accurately soldering with a better bond.

Actually, if anyone knows of a definition that describes the difference between brazing and soldering while encompassing 'active braze alloys', I would appreciate seeing it.

tom


Thomas J. Walz
Carbide Processors, Inc.

http://www.carbideprocessors.com

Good engineering starts with a Grainger Catalog.

 

[unclesyd]

tomwalz.
Look for 450C as the demarcation line. I've seen this number in several papers. After reading the AZOM article you might want to get the original article in Materials World.

Here is the Azom paper.

http://www.azom.com/Details.asp?ArticleID=1079

Here is the original paper.
Source: Materials World, Vol. 7, no. 11, pp. 686-88 November 1999.
Primary author: Dr. John A Fernie and Dr. Kane I Ironside

You can get it here for very reasonable price.

http://www.lindahall.org/

 

[TVP]

ASM HANDBOOK Volume 6 Welding, Brazing, and Soldering uses the same threshold (450 C) to differentiate brazing from soldering.