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Tantalum caps “popcorn”

Views: 3408

#82436

Tantalum caps “popcorn” | 25 April, 2019

I am having fractures in my tantalum caps, I believe it is from out fading but I am having a hard time convincing others. Where they are not hermatically sealed are thes fractures a concern? Moisture is entering the body regardless of the fractures? Does any one have experience with this type of issues with tantalum caps?

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#82437

Tantalum caps “popcorn” | 25 April, 2019

Out gassing not out fading

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#82447

Tantalum caps “popcorn” | 25 April, 2019

Numerous technical papers on the web document the moisture sensitivity of tant caps. Here's one: https://nepp.nasa.gov/DocUploads/CE5125B5-E0EB-4CFA-8867BE3F3E342CA5/moisture%20effect%20Ta%202C%20M.pdf

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#82459

Tantalum caps “popcorn” | 27 April, 2019

I have read this I guess the question I should be asking is what have you done when finding these? IPC says it enters the body so it is a defect many in my group feel it should not be because they are not hermacticaly sealed anyway. I am needing thoughts and experiences Thanks

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#82460

Tantalum caps “popcorn” | 27 April, 2019

Your ppl are correct, the capacitor is not sealed. So, it is perfectly acceptable for the capacitor to have absorbed moisture.

If your ppl don't either prevent moisture absorption or remove the moisture prior to soldering, their component could fail.

Want proof? Follow proper MSD controls on a lot of boards and then compare the results with you current practices.

* J-STD-033 Standard for Handling, Packing, Shipping, and Use of Moisture/Reflow Sensitive Surface Mount Devices

* J-STD-020. Moisture/Reflow. Sensitivity Classification for Nonhermetic Surface. Mount Devices.

* IPC-1601 Printed Board Handling and Storage Guidelines

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#82461

Tantalum caps “popcorn” | 27 April, 2019

Thanks I appreciate the information

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