Friction and Wear Characteristics of Bio-Lubricants Containing Clove Oil as Antioxidant

Vegetable oils as bio-lubricants have poor oxidation stability due to the unsaturated fatty acids in their composition. The oxidation in bio-lubricants can occur because they are exposed to heat, light, and oxygen. In this research, clove oil was used to reduce oxidation in vegetable oils. The effects of blending clove oil (0, 5, and 10% wt) with virgin coconut oil (VCO), hydrogenated coconut oil (HCO), and palm oil that have been exposed to oxygen for 30 days have been investigated. Viscometer and pin-on-disk tests were used to determine the physical and tribological properties of the bio-lubricants. The results show that the addition of clove oil to these oils could reduce the oxidation process. It was indicated by the reduced percentage increase in the dynamic viscosity of 10% wt clove oil in VCO of around 5.41% for 30 days. Results of wear rate indicated that the effect of adding clove oil to VCO and HCO was better than that of palm oil, where the wear rate of VCO and HCO decreased with an increasing clove oil composition. Meanwhile, their coefficients of friction were only affected at low speeds (500 rpm).