Zinc Whiskers

SEM image of Zinc Whiskers [Click image for larger size] EDS of a Zinc Whisker [Click image for larger size]

Zinc Whiskers

Zinc whiskers have been responsible for increased system failure rates in computer server rooms. Zinc whiskers grow from galvanized (electroplated) metal surfaces at a rate of up to 1 mm per year with a diameter of a few micrometers. Whiskers can form on the underside of zinc electroplated floor tiles on raised floors due to stresses applied when walking over them; and these whiskers can then become airborne within the floor plenum when the tiles are disturbed, usually during maintenance. [1] Whiskers can be small enough to pass through air filters and can settle inside equipment, resulting in short circuits, voltage variances and other signal disturbances. These events are capable of causing equipment service interruptions or failures. [2]

 Zinc coated steel rails and pedestal for raised floorsZinc coated floor tile examined under bright white light

 

If you suspect whisker growth on floor panels, you can remove a panel and shine a flashlight on the steel surface at an angle. Look for a reflective sparkling or twinkling on the surface. If there is a reflection, it is likely there is whisker growth. To truly confirm the existence of zinc whiskers, we recommend that you take a a standard piece of scotch tape and adhere it to the side of the panel, rail, or pedestal suspected of containing the whiskers. Then remove the tape and insert it into a plastic bag. We will observe the contaminants contained on a section(s) of the tape by a Scanning Electron Microscope (SEM), and subsequently perform elemental analysis on the Zn-whisker itself by Elemental Dispersive Spectroscopy (EDS). In addition to the SEM Images and EDS spectrums, the report will contain whisker sizes and total percentage contained within a field of the tape sample.

 

1. http://en.wikipedia.org/wiki/Whisker_(mettalurgy)

2. http://www.airplenum.com/zinc_whiskers_article1.pdf, "Tate Technical Bulletin #277, Rev. 1, Zinc Whiskers"

3. Optical images from Data Clean, http://www.dataclean.com/zinc-whiskers.htm

 

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