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 >>>> >>>> >>>>