netneut
finishing.com -- The Home Page of the Finishing Industry
A website for Serious Education, promoting Aloha,
& the most FUN smiley you can have in metal finishing


Finishing.com has been free for 22 years,
but without net neutrality we could soon
cease to exist. Do us a solid, click on
the banner, and contact congress today!
HomeFAQsBooksHelpWantedAdvertiseForum
topic 3762

Tin Whisker problem


(1999)

I am a hardware engineer. I have a problem of shorting two pins of a terminal block of a module on the field. This 5 mm spacing terminal block pins are tin plated. I think the cause of this shorting is whiskers (Based on articles of NASA about whisker). I wonder if there is way to recreate the short, in other words how to generate the whisker growth to have a short between two pins and how to prevent the short. Thanks.

[name removed at writer's request]

Whiskers are believed to be a stress-relief process that purer metals tend to undergo spontaneously. Consequently the way to produce them is with highly stressed pure tin deposits. The way to discourage them is via a stress relieving process and/or by including alloying metals in the deposit.

Historically, lead was used and is useful in even fairly low concentration. But with environmental pressures against lead, whiskering has become a bigger problem even though it was thoroughly researched decades ago. You might do a lit search about tin-bismuth as I understand that a small amount of bismuth in the deposit is effective in minimizing whiskering.

Our FAQs will link you to several other letters here about tin whiskers.

Ted Mooney, finishing.com Teds signature
Ted Mooney, P.E. RET
finishing.com
Pine Beach, New Jersey


(1999)

It sounds like a small amount of Lead in the Tin deposit would eliminate the whiskering (2%-10%). Hot Oil Flowing will also help if you don't want to use Lead. I've been looking in to the Tin/Bismuth deposits and their use in extreme cold environments. I know that they help control Tin Pest problems (flaking) at temperatures below -42C. The Aerospace Industry is especially interested in this. I've been trying to find a supplier for this but they are still in development.

jim conner
Jim Conner
Anoplex - Dallas, Texas USA



This public forum has 60,000 threads. If you have a question in mind which seems off topic to this thread, you might prefer to Search the Site

ADD a Q or A to THIS thread START a NEW THREADView This Week's HOT TOPICS

Disclaimer: It's not possible to diagnose a finishing problem or the hazards of an operation via these pages. All information presented is for general reference and does not represent a professional opinion nor the policy of an author's employer. The internet is largely anonymous & unvetted; some names may be fictitious and some recommendations may be deliberately harmful.

  If you need a product/service, please check these Directories:

JobshopsCapital Equip. & Install'nChemicals & Consumables Consult'g, Train'g, SoftwareEnvironmental ComplianceTesting Svcs. & Devices


©1995-2017 finishing.com     -    Privacy Policy
How Google uses data when you visit this site.