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MOTORINDIA
l June 2012
A number of years ago, Tim-
ken and other bearing companies
started using coatings on rollers
for niche bearing applications. The
most widely used coating for bear-
ing rollers was a tungsten carbide
containing amorphous hydrocarbon
coating commonly called tungsten
diamondlike carbon. In late 2008,
Timken performed extensive appli-
cation testing of bearings with this
coating, which was commercially
available from a number of different
sources. Researchers concluded that
this coating was not durable enough
to provide performance improve-
ments for the majority of bearing
applications.
Wanting to understand why this
was the case, the team performed
an in-depth analysis of the coating
and identified a defect that might be
responsible for the limited durabil-
ity of the coating. A second study
focused specifically on eliminat-
ing that defect during the coating
deposition process, and a new coat-
ing without this defect was created.
When Timken tested bearings with
this new coating on the rollers, the
bearings performed far better than
any bearings the company had ever
tested.
For example, Timken research
saw a 3.5 to four times improve-
ment in the fatigue life of roller
bearings. After reviewing over 100
years of data, it was concluded that
this coating may be the most sig-
nificant improvement that has been
seen in roller bearing performance
to date.
Timken’s experience with debris-
resistant bearings for mining ap-
plications dates back to 2003. The
prior coating technology targeted
increased performance in high de-
bris environments operating with
marginal lubrication conditions.
This enhanced product offering with
Timken’s new coating applied to
rollers has increased equipment up-
time at mines throughout the world.
In addition to improved debris
resistance and unparalleled low
lambda fatigue life, this new coat-
ing technology further expands the
technology
Since the late 1990s, coatings on bearing rollers
provide wear resistance, debris resistance and
friction reduction for demanding customer applica-
tions. However, more than a decade of intensive re-
search and development resulted in a new coating
technology that expands the performance of rolling
element bearings well beyond the previous limits.