Well, the ENIG is much thinner than HASL solder, AND it has a higher thermal conductivity (40.9 W/m-K for Sn63 vs. 90.7 w/m-K for Ni and 317 for Au), both of which make it better for heat transfer.
If the contact between the surfaces is equally good (it will be easier to get better contact with soft solder) ENIG wins hands down. But it may require more pressure to give equally good contact area with ENIG.



Timothy Reeves
Technical Service Engineer - Matsushita Electronic Materials, Inc.


-----Original Message-----
From: d. terstegge [mailto:[log in to unmask]]
Sent: Monday, March 17, 2003 2:33 AM
Subject: Heat transfer from ENIG board to aluminium casing


Hi Technet,

We are in the process of converting some of our boarddesigns from HASL
to ENIG conductor finishing. Now one of our designers is worried about
the effect that this change may have on heat transfer from the plated
board-edges to the aluminium casing on which the board is mounted. He
feels that the heattransfer from leadtin to aluminium is better that for
nickel/gold to aluminium, possibly resulting in heat problems in the end
product.

Any ideas on this ?

Daan Terstegge
Thales Communications
Unclassified mail
Personal Website: http://www.smtinfo.net

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