NASA

SILVER WHISKER Photo Gallery

The following Images and Technical Information are Courtesy of 
Dr. Bella Chudnovsky - (formerly of Schneider Electric/Square D)  (513)-459-7692

Low Voltage Circuit Breaker

The whiskers below are SILVER WHISKERS. They were found growing on primary contacts, finger clusters and other current conductors of circuit breakers in switchgear at pulp recycling mill. The current carrying parts are made of silver-plated copper. Most of the whiskers are made of silver with 1-3 % of copper. Just in two months after previous cleaning, the whisker grows up to several inches (6-8 cm) long and up to 0.04 in (1 mm) thick. Major environmental factor to initiate the growth is relatively low concentration of Hydrogen Sulfide (H2S). As soon as a thick enough layer of silver sulfide has been formed, metal filaments start to grow virtually everywhere but most intensely in locations usually having elevated temperature while electrical units are energized. The surface of the whiskers long exposed to atmosphere is contaminated with silver sulfide. The growth eventually leads to catastrophic thermal failure.

1.  Optical Image of Silver Whiskers on Finger Clusters after failure 

2.  Optical Image of Silver Whiskers on Primary Contacts after failure (1)

3.  Optical Image of Silver Whiskers on Primary Contacts after failure (2)

4.  Optical Image of Silver Whiskers on Primary Contacts after failure (3)

5.  SEM Image of Silver Whisker (close-up)

6.  SEM Image of Silver Whiskers (group)

7.  SEM Image of Silver Whiskers (nursery)

8.  SEM Image of Silver Whisker (pig tail)
  1. Optical Image of Silver Whiskers on Finger Clusters after failure 
  2. Optical Image of Silver Whiskers on Primary Contacts after failure (1)
  3. Optical Image of Silver Whiskers on Primary Contacts after failure (2)
  4. Optical Image of Silver Whiskers on Primary Contacts after failure (3)
  5. SEM Image of Silver Whisker (close-up)
  6. SEM Image of Silver Whiskers (group)
  7. SEM Image of Silver Whiskers (nursery)
  8. SEM Image of Silver Whisker (pig tail)

See Also Dr. Chudnovsky's Technical Paper:  Degradation of Power Contacts in Industrial Atmosphere: Silver Corrosion and Whiskers", 48th IEEE Holm Conference on Electrical Contacts 2002

NOTE:  The growth mechanism of SILVER WHISKERS is NOT believed to be analogous to Tin and Zinc Whisker formation.  Nevertheless, whiskers formed on silver- coated contacts in a sulfur-rich environment pose a serious reliability hazard.
 
Responsible NASA Officials:

   Michael Sampson/NASA GSFC Code 306
   Dr. Henning Leidecker/NASA GSFC Code 562		 Additional Researchers: 

   Jong Kadesch/Orbital Sciences Corp.
   Jay Brusse/Perot Systems

Last Updated:

February 5, 2009

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This website provides information about tin whiskers and related research. The independent research performed during the past 50+ years is so vast that it is impractical to cover all aspects of tin whiskers in this one resource. Therefore, the absence of information in this website about a particular aspect of tin whiskers should NOT be construed as evidence of absence.

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