The results of the studies on the formation of surface and boundary layers in commercial lithium (LT4-S3) and calcium (STP) greases near the walls of six different materials are presented. Two elastomeric materials (nitrile-butadiene rubber (NBR), silicone rubber (MVQ/VMQ)), two thermoplastic materials (polyoxymethylene (POM), polyethylene (PE)), and two metal (copper C11000 and steel 304) alloys were used in the tests. The tests were carried out using a rotational rheometer operating in the plate/plate configuration. Structural viscosity–shear rate curves were determined and dynamic oscillatory tests were carried out. The tests have shown that the metal alloys have the highest capacity to adsorb grease thickener particles on their surface. The elastomeric materials have the smallest effect on the change in structural viscosity in the vicinity of the wall, which indicates their low capacity to form a surface layer in the tested commercial greases.
The Wall Effect in the Flow of Commercial Lubricating Greases
Higher Vocational State School in Kalisz,
Nowy Swiat 4,
Kalisz 62-800, Poland
of Machine Design and Tribology,
Wroclaw University of Technology,
Ignacego Lukasiewicza 7/9,
Wroclaw 50-371, Poland
Contributed by the Tribology Division of ASME for publication in the JOURNAL OF TRIBOLOGY. Manuscript received January 6, 2015; final manuscript received March 10, 2016; published online May 17, 2016. Assoc. Editor: Mihai Arghir.
Czarny, R., Paszkowski, M., and Knop, P. (May 17, 2016). "The Wall Effect in the Flow of Commercial Lubricating Greases." ASME. J. Tribol. July 2016; 138(3): 031803. https://doi.org/10.1115/1.4033334
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