Continued from page 7
Figure 4. EHL film thickness measurements of neat base oils.
We determined that thicker films in boundary and mixed film lubrication regimes were observed for Elevance Aria™ WTP 40. Elevance’s improved surface affinity delivers thicker films and improved wear control potential at slow speeds and start up.
Thanks to ongoing research efforts with Argonne National Laboratoryv
, Elevance Aria™ WTP 40 was evaluated against
PAO 40 in a Micropitting Rig (MPR). The MPR and test specimens have been designed to reproduce the lubricated contact conditions that can lead to either micro- or macro-pitting. This instrument provides additional information about base oil properties under realistic contact pressures and film thickness. In the example below the MPR was run at 90o
C with 300N force at speeds of 3/ms and slide-to-roll
ration of 20 percent. Following a four-hour run time, the test specimens were evaluated microscopically to evaluate surface changes. Noted in Figure 5, the diagonal blue markings are clear indication of wear scars in the PAO sample versus the Elevance Aria™ WTP 40 sample. The vertical blue marks are non-micropitting artifacts of the rig and specimen.
Conclusion
Gear oil specifications are beginning to reflect demand for higher lubricant performance. The players developing lubricants and maintenance strategies for this extreme application are paving the way for a new standard in gear and bearing lubrication. Elevance renewable building blocks offer a new tool for synthesizing novel, high-performance lubricant base stocks. Covalently bonded ester to PAO architecture offers potential for improved friction and wear versus conventional and metallocene PAO. Elevance Aria™ WTP 40 is a base stock that can help meet today’s high-performance base stock demands for severe applications. The molecular design of Elevance Aria™ WTP 40 with chemically bound ester shows tribological advantages over the PAO/ester blend in both friction and wear performance. The improved performance of Elevance Aria™ WTP 40 could be attributed to its stronger and thicker adsorbed fluid film and intramolecular interactions. Elevance Aria™ WTP 40 is showing encouraging results and more formulating and testing will help demonstrate differentiated performance and suitability for additional applications.
i) Boyde, S (2002). Green lubricants: Environmental benefits and impacts of lubrication. Green Chemistry 4: 293-307.
ii) Clark, J (2013). Turbine Maintenance: Pay now or surely pay later. North American Windpower. Volume 10. Number 9.
iii) Smith, P (2014) Wind Power Offshore: Siemens wind makes quarterly loss.
iv) Elastohydrodynamic lubricant (EHL) film thickness measurements were obtained by Dr. G. Biresaw USDA-ARS-NCAUR-BOR, Peoria, Illinois.
v) Micropitting data was obtained by Dr. Aaron Greco at Argonne National Laboratory, Lemont, Illinois.
LINK
www.elevance.com
Figure 5. Micropitting Rig data for neat base oils.
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LUBE MAGAZINE NO.133 JUNE 2016
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