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Subject:
From:
Yuan-chia Joyce Koo <[log in to unmask]>
Reply To:
TechNet E-Mail Forum <[log in to unmask]>, Yuan-chia Joyce Koo <[log in to unmask]>
Date:
Wed, 6 Sep 2017 18:09:50 -0400
Content-Type:
text/plain
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text/plain (78 lines)
I see, RF frequency Ni is killer for skin effect... depend upon what  
the beast  is... 200 W RF?  scary stuff to start with if it is high  
frequency that need to consider eliminate  Ni...
jk
On Sep 6, 2017, at 5:59 PM, David Hillman wrote:

> Hi Joyce - the barrier layer can be either nickel or copper  
> depending on
> the component supplier. Obviously nickel is a better materials  
> choice for
> soldering process robustness but in terms of electrical  
> characteristics,
> some circuit designs work better with copper.
>
> Dave
>
> On Wed, Sep 6, 2017 at 4:58 PM, Yuan-chia Joyce Koo <[log in to unmask]>
> wrote:
>
>> http://www.electronicdesign.com/boards/rohs-implementation-challenges
>> see the cross section of Ceramic cap - metallization got Ni  
>> layer... not
>> seen on your image.  hopefully, it is not MFG missing a process  
>> (or cheap
>> stuff for low temp/ Ag adhesive potting type).
>> On Sep 6, 2017, at 3:01 PM, Yuan-chia Joyce Koo wrote:
>>
>> did it missing a Ni plating?  http://www.johansondielectrics
>>> .com/understanding-ceramic-capacitor-terminations
>>> best of luck.
>>> jk
>>> On Sep 6, 2017, at 12:25 PM, Giamis, Andy wrote:
>>>
>>> Hi TechNetters,
>>>>
>>>> Here’s something I have not seen before.
>>>> I have seven different ‘theories’ for what’s happening here.
>>>> Three of which do not involve mythical creatures, illegal  
>>>> substances or
>>>> the alignment of celestial bodies.
>>>>
>>>> This capacitor is on a path that sees a lot of RF power.
>>>> The unit went through 20 cycles of -70C to +115C while at nominal
>>>> power.  Temperature sensing suggests this device could be  
>>>> hitting 170C.
>>>> No, we normally don’t test to these extremes.
>>>> The PCB has ENiG finish and the solder is SAC.   This is normal  
>>>> SMT, no
>>>> rework.
>>>>
>>>> I think I know in general what happened, but I am surprised.
>>>> I don’t have an explanation for the formation of the big pocket  
>>>> on the
>>>> right.
>>>> Has anyone ever come across any solder joints like this?
>>>>
>>>> Thanks Steve for uploading the pictures (links below).
>>>>
>>>> http://stevezeva.homestead.com/pockets_25.jpg
>>>>
>>>> http://stevezeva.homestead.com/Pockets_CS.jpg
>>>>
>>>> http://stevezeva.homestead.com/Pocket-left.jpg
>>>>
>>>> http://stevezeva.homestead.com/Pockets-right.jpg
>>>>
>>>>
>>>> Best Regards,
>>>> Andy
>>>> Andrew C. Giamis
>>>> Senior Failure Analysis Engineer
>>>> CommScope
>>>> 2601 Telecom Pkwy
>>>> Richardson, TX, 75082, USA
>>>>
>>>>
>>>>

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