User Tools

    To create and edit articles, please register and log-in

Main Menu : categories & index etc.

Main menu
Click categories to expand


A-Z listingplugin-autotooltip__plain plugin-autotooltip_bigA-Z listing

This is an alphabetical index of all content pages.


Other categories

Utilities

Contact
Register
Sandbox

Also see

Importance Ratings
News
Legal
Donate/Sponsor
Curator's rationale
AI Policy



Twitter feed 𝕏



Feeds + s.e.o. etc.
rss / xml feed
sitemap file
A-Z listing (archived)


Indexed under : Physics / General

Wikenigma - an Encyclopedia of Unknowns Wikenigma - an Encyclopedia of the Unknown

Metallic whiskers

From the early days of electronics, it was found that some metallic components, especially the lead-based (Pb) and tin-based (Sn) soldered connections, tend to slowly grow conductive 'metal whiskers' (MWs) which can cause short-circuits and severely affect the reliability of systems.

Even though lead has been largely removed from solder composition, it's been found that the replacement metals also grow whiskers. In addition, the very extensive miniaturisation of electronic components (and the tiny 'solder pads' they're connected to) means that even extremely short whiskers can cause problems.

The whiskers - which vary in diameter from tens of nanometers to microns in diameter, and hundreds of nanometers to millimeters in length, have now been found to also grow on zinc, cadmium, indium, gold, silver, and many other metals.

They grow from accumulations of metal atoms at the root of the whisker rather than the tip.

There is currently no agreed theory on the physics behind MW growth.

Current theories and test methods DO NOT have predictive power of the time-dependence of Whisker Density, Length or Thickness Distributions. A useful theory should identify what we must control to make confident predictions. Such a theory has remained elusive.“

Source: The Art of Metal Whisker Appreciation: A Practical Guide for Electronics Professionals NASA Goddard Space Flight Center.

It's currently thought that whisker growth is encouraged by compressive mechanical stresses - but the exact mechanism is unknown despite intensive research over many decades.

Further technical reading :Physics and applications of conductive filaments in electronic structures: from metal whiskers to solid state memory PhD thesis from Dipesh Niraula, University of Toledo, 2019.

Importance Rating


    Please share this page to help promote Wikenigma !

Dear reader : Do you have any suggestions for the site's content?

Ideas for new topics, and suggested additions / corrections for older ones, are always welcome.

If you have skills or interests in a particular field, and have suggestions for Wikenigma, get in touch !


Or, if you'd like to become a regular contributor . . . request a login password. Registered users can edit the entire content of the site, and also create new pages.

( The 'Notes for contributors' section in the main menu has further information and guidelines etc.)

Automatic Translation

You are currently viewing an auto-translated version of Wikenigma

Please be aware that no automatic translation engines are 100% accurate, and so the auto-translated content will very probably feature errors and omissions.

Nevertheless, Wikenigma hopes that the translated content will help to attract a wider global audience.

Show another (random) article

Further resources :

DOKUWIKI IMPLEMENTATION DESIGN BY UNIV.ORG.UK DECEMBER 2023