This is a common problem in the past in my youth and now also in a lead-free
world. Remember its not just capacitors that can have problems. In the case
of capacitors it can be seen in manual soldering and in wave soldering if
there is no barrier layer of nickel. 

Any parts without barrier layers may be affected. There are a few examples
of this and standard copper dissolution in the NPL Defect Database. Happy to
add your examples to the site if you like at
http://defectsdatabase.npl.co.uk it helps users to have a good reference
source to defects.

The issue of barrier layers is covered in the report and process guide
produced at NPL with good examples and suggestions on this issue, also
provides examples other parts that can be an issue without a barrier layer
or increasing the thickness of existing barrier layers in a lead-free world.

You can request a copy of the Copper Dissolution Guide and Industry Report
from [log in to unmask] 

The content was also covered in my monthly page in Global SMT magazine see 
http://content.yudu.com/Library/A18cr7/GlobalSMTPackaging96/resources/6.htm 

Bob Willis
2 Fourth Ave, Chelmsford, Essex, CM1 4HA England
Tel: (44) 1245 351502
Fax: (44) 1245 496123
Mobile: 07860 775858
www.ASKbobwillis.com
www.SolderingStandards.com 

PCB Design for Manufacture & Assembly Workshop 15th October
www.ASKbobwillis.com 
PCB Inspection & Quality Control Workshop 3rd November
www.ASKbobwillis.com/faworkshops.pdf
Book Bob's "Step by Step Failure Analysis Workshop" 4th November
www.ASKbobwillis.com/faworkshops.pdf

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Peter L
Sent: 20 July 2009 18:36
To: [log in to unmask]
Subject: [TN] Leadfree compatibility of Silver Palladium terminations?

Hi,

I am wondering if anyone has experienced issues with leadfree reflow
soldering 
small discrete chips (0805) with silver palladium terminations? According to
one 
particular manufacturer (EPCOS) they do not approve it and claim that the 
termination will be "damaged" under leadfree processing temperature. I am 
curious to know the reason behind. Thanks.


http://www.epcos.com/web/generator/Web/Sections/ProductCatalog/Protectio
nDevices/CeramicTransientVoltageSuppressors/PDF/CTVS__Soldering,property=
Data__en.pdf;/CTVS_Soldering.pdf

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