Why Zinc Whiskers Remediation is so Important !
Zinc whiskers are a serious threat that can grow in data centers and WILL
cause hardware failures. NESCop Technologies decontamination services assure its
clients a data centre free of zinc whiskers, eliminating many potential data corruption
and server performance problems in the process. NESCop technicians will extract
all zinc whiskers that threaten your systems with full certification from NESCop.
ARE ZINC WHISKERS GROWING IN YOUR COMPUTER ROOM?
- Are you having unexplained hardware failures – particularly disk drives and power
- Are you having unexplained data corruption problems?
- Do your problems get more frequent or severe after you move equipment or work in
- Have you installed the latest lightning fast server or CPU only to find it doesn’t
seem as reliable as your old legacy system?
If you answered Yes to any of the foregoing questions, you might have Zinc
Formation and Characteristics
Zinc whiskers are a phenomenon that can occur on bare metal surfaces. Metal surfaces
are coated with zinc in a galvanisation process to help protect them from corrosion.
While several techniques are used, such as hot-dip or spraying, whisker growth appears
to be limited to electroplated samples. The whiskers are zinc crystals formed by
the degradation (corrosion) of the galvanised metal surface. Several industry studies
have shown that whisker growth is dependent on internal stresses during the plating
process. The crystalline structure within the metal will attempt to relieve the
internal stress by enlarging the structure through the growth of crystals. The growth
path is outward and the material is literally pushed out of the surface of the metal.
These crystalline growths (whiskers) are typically 2 microns in diameter and over
time (many years) can grow to be several millimetres in length, up to 10mm although
typically <1mm. Under proper lighting, they can be visible to the naked eye on surfaces.
The whisker formation process consists of an unpredictable incubation period, typically
lasting months or even years without any growth at all, followed by a period of
growth at rates as high as 1mm per year. Some zinc coated surfaces may never grow
whiskers. Unfortunately, accelerated techniques do not currently exist to predict
if, when, and to what extent a zinc-coated surface will produce whiskers.
Effects of Zinc Whiskers: System Failures
While whiskers remain attached to their source i.e. floor panel, pedestal etc they
are basically benign, however when the whiskers are disturbed and dislodged they
become airborne and circulate freely throughout the environment. Disturbance is
likely to be caused by routine maintenance activities in a data centre, including
lifting, sliding and reinstalling of access floor tiles and the pulling of electrical
cable in the subfloor space. For efficient cooling the forced air-system typically
pressurizes the subfloor space with chilled air. Perforated floor tiles and air
vents provide channels through which the cool air, including the zinc whiskers,
can pass into the above floor space. Ultimately many whiskers can pass into the
electronic hardware through vents and fans on the equipment. Once inside the equipment
zinc whiskers, which are electrically conductive structures, can cause various electrical
failures, ranging from intermittent to permanent short circuits. Whisker debris
can also become a physical impediment to moving parts or obscure optical surfaces
and sensors within some equipment (such as disk or tape drives) The first identification
of zinc whiskers, and its associated system failures, occurred in the 1940′s. Renewed
interest has arisen triggered by the apparent increase in reported failures. Several
factors appear to contribute to the apparent increase:
- Continuous miniaturisation of electronic components technological advances have
led to more densely packed circuitry and tighter spacing between conductors, therefore
smaller conductive particles can now cause shorts.
- Reduction in circuit voltages and currents newer systems operate at lower levels
and therefore energy from these components may not be sufficient to melt a zinc
whisker, resulting in increased risk for permanent shorts.
- Age of existing floor structures many facilities now have flooring that has been
in place for in excess of 10years thus whiskers are of a length capable of bridging
exposed conductor spacings.
- Increased maintenance and up-grade activity in raised-floor facilities any activity
that involves moving flooring can dislodge whiskers, in today’s high-tech environments
it is more commonplace for computing facilities to undergo regular maintenance activity,
i.e. adding, removing hardware, repositioning and reconfiguring equipment etc.
- During a one-month period, a NASA data centre experienced at least 18 catastrophic
power supply failures in newly installed mass memory storage devices. The ensuing
failure investigation determined that the causes of failure were electrical short
circuits’ These had been caused by small metallic filaments growing on the underside
of raised floor tiles and support structures that had been dislodged during maintenance
and distributed throughout the data centre by forced air cooling systems.