Scientists from China conducted an experiment to investigate the influence of ionic liquid [HMIM]BF4 as an additive on the tribologicaal properties of castor oil. The experiment was done by using a four-ball friction test rig.
The results showed that a small amount of ionic liquid can postpone the peak coefficient of friction and decrease the wear behaviour. In addition, the chemical adsorption of castor oil and ionic liquid on a steel surface is more significant than physical adsorption. Thus, the study could be of great importance to understand the potential engineering application of castor oil.