Abstract:
Mechanical components involving surface interaction requires lubrication at all costs to
reduce friction and wear in order to avoid mechanical failure. Majority of lubricants used
around the world are from mineral based sources. These sources are not infinite and pose
danger to the environment due their toxic nature and disposal problems. This awareness
has given rise to the formation of environmental friendly lubricants which are obtained
from renewable sources such as bio-lubricants. The low thermal stability of bio-lubricants
has caused the limitation on it use as compared to mineral based oils. Certain additives are
used to increase the thermal stability of these bio-lubricants and further enhance their
tribological properties. Ionic liquids are the most common solvents used as an additive to
the bio-lubricants. These organic salts are environmentally friendly and have proved to be
beneficial to the tribological properties of bio-lubricants. The extent to their effectiveness
in enhancing the tribological performance of a lubricants greatly depends upon
compatibility and its miscibility. Ionic liquids are generally composed of anions and cations
and make strong interaction with polar base oils.
In this research work, Bis (2-Ethylhexyl) phosphate ionic liquid was used an additive to
the base test lubricants including PAO and bio-lubricants as Cotton seed oil (CSO), Rattan
jot oil (RJO), Waste cooking oil (WCO) at various operating conditions. A four ball
tribometer was used to perform the tests for all lubricants with and without the addition of
ionic liquid as an additive. To analyze the wear scar diameter on each sample a digital
microscope was used. Results were obtained and analyzed, and it was found that addition
of ionic liquid has not much improved the performance of PAO but significant effects can
be seen for the case of bio lubricants. Where CSO performed best at lower operating loads
and RJO performed best at higher operating loads due to its inherent load carrying capacity.
