COATINGS AND LUBES
[Dry Film Lubricants]
Thermal Barrier Coatings
Dry Film Lubricants
Dry film lubricants, also
known as solid film lubricants, provide a lubricating film that reduces
friction, inhibits galling and seizing and in some instances can aid in
dispersing heat. The appearance is generally a charcoal gray and takes on
a sheen upon burnishing. They are slippery and provide an extremely low
coefficient of friction.
The two most important components are the binders and lubricating
ingredients. Without a good binder the coating will not stay in place and
will simply cold flow or buff off in operation. Similar coatings using the
same pigments but different binding systems can show a wide variation in
load carrying abilities, ranging from 100,000 psi to over 350,000 psi .
The pigments determine the actual lubricating potential. PTFE, as an
example, is listed as having the lowest coefficient of friction (COE).
However, under high speed and load, the COE of PTFE degrades while that of
MOS2 (Moly) improves, until it is significantly better than PTFE.
Selecting the proper ingredients can make or break a coating.
One of the obvious reasons for using a lubricating coating is to reduce
friction, which improves wear, extends part life and frees up H.P.
normally lost to friction. A second major benefit is a reduction in part
temperature. This is especially important to such parts as valve springs.
Here the pigment choice is critical as certain ingredients can trap heat
in a part. Not all coatings are created equal. . It is recommended by TECH
LINE that coatings using PTFE be avoided in these cases. Contact our TECH
DEPT before choosing a dry film lubricant.