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Reducing the effect of three‐body abrasive wear by adding polymeric powder to lubricating grease
Author(s) -
Ali W. Y.,
Mousa M. O.,
Khashaba M. I.
Publication year - 1996
Publication title -
lubrication science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.632
H-Index - 36
eISSN - 1557-6833
pISSN - 0954-0075
DOI - 10.1002/ls.3010080404
Subject(s) - grease , materials science , abrasive , rubbing , composite material , lubrication , polyethylene , high density polyethylene , low density polyethylene , lapping , lubricity
The present paper reports on work aimed at improving the abrasive wear resistance of surfaces lubricated with contaminated greases. The intended improvement can be achieved by reducing the effect of wear occurring between the abrasive particles and the rubbing surfaces. Different polymeric thickeners in powder form, such as high‐density polyethylene (HDPE), low‐density polyethylene (LDPE), polyvinylchloride (PVC), polyamide (PA6) and polymethylmethacrylate (PMMA), were added to lithiumbased grease. The wear resistance and the coefficient of friction of cylindrical steel specimens were examined using a cross‐pin test machine. The test machine provides concentrated contact under mixed lubrication conditions. Wear was measured on the stationary test specimen by the wear scar diameter, using an optical microscope, with an accuracy of ±1 μm. The frictional torque generated between the rubbing surfaces was measured using a full bridge strain gauge measuring cell attached to the stationary test specimen holder. The experiments were performed using clean and contaminated lubricating greases to which Air Cleaner Fine Test Dust (SCFTD) was added to the greases at a concentration of 10 wt.%. The results show that the effect of the abrasive contaminants can be reduced by the addition of polymeric powders. However, the addition of polymer to lubricating grease at relatively high concentration (more than 35 wt.%) has no effect on the antiwear action of the lithium grease. Further, the addition of polymeric powder with a particle size relatively greater than that of the contaminant can be considered as a useful method of eliminating the cutting process of the three‐body abrasive mechanism introduced by the presence of the hard contaminant particles.