4000 3500 3000 2500 2000 1500 1000 500
.5
0
1
1.5
2
Absorbance
Wavenumber (cm
-1
)
Phosphate Ester Contamination
in Petroleum-Based Gear Oil
50%
of lubrication professionals
use FTIR testing in their oil
analysis program, according
to a recent survey at
MachineryLubrication.com
be expected when two oils with different
chemical compositions are added together
because of cross-contamination. The fi gure
below shows the FTIR spectrum of a blend of
a polyalphaolefi n-based synthetic oil and a
phosphate ester electro-hydraulic control
(EHC) fl uid. By recording the FTIR spectrum
of the suspected blend along with the known
new oil reference spectra of the pure polyal-
phaolefi n and pure EHC fl uid, this accidental
mixing can be confi rmed. In fact, when an
unknown contamination issue is suspected,
it often is advisable to immediately run an
FTIR spectrum in conjunction with a fresh
new oil reference whenever possible.
FTIR is a valuable addition to any oil
analysis program. By understanding how the
technique works as well as its strengths and
limitations, oil analysts and end users can
obtain a vast amount of information when
utilizing it alongside other standard test
methods and strategies.
About the Author
Jeremy Wright is the vice president of tech-
nical services for Noria Corporation. He serves
as a senior technical consultant for Lubrication
Program Development projects and as a senior
instructor for Noria's Machinery Lubrication I
and II training courses. He is a certifi ed mainte-
nance reliability professional through the Society
for Maintenance and Reliability Professionals,
and holds Machine Lubricant Analyst Level III
and Machine Lubrication Technician Level II
certifi cations through the International Council
for Machinery Lubrication. Contact Jeremy
at jwright@noria.com.