Vegetable oils have gained worldwide concern due to environmental issues since it is biodegradable, renewable and environmental-friendly. However, the limitations of vegetable oils such as having low oxidation stability and poor low temperature properties need to be solved. The purpose of this paper is to evaluate the tribological behavior of refined, bleached and deodorized (RBD) palm kernel and RBD palm stearin by using a modified pin-on-disc tester. The influence of an anti-wear/extreme pressure (AW/EP) additive on the anti-friction and anti-wear characteristics was also evaluated. The experiment was carried out by varying zinc-dialkyl-dithiophosphate (ZDDP) additive concentration of 1wt%, 3wt% and 5wt%; load of 1kg, sliding speed of 2.5 m/s, test duration of 60 minutes and at room temperature. The findings have revealed that without an additive, RBD palm kernel and RBD palm stearin have high friction coefficient and wear as compared with synthetic oils. The addition of additives helps in the improvement of tribological performance of tested vegetable oils. It can be concluded that vegetable oils have a great potential to be used as a petroleum-based substitute.

This study compares tribological performance of refined, bleached and deodorized (RBD) palm kernel (PK) as an alternative lubricant. An analysis was made for chemically modified RBD PK with zinc dialkyl dithiophosphate (ZDDP) additive to determine its tribological performance using modified pin-on-disc tribotester. Commercial mineral oil (SAE 40) was used as the benchmark in this study. The conditions for this experiment are sliding speed at 1.5 m/s, a normal load at 9.81 N, weight percentage of ZDDP for 0, 3 and 5%, lubricant quantity of 2.5 ml and test duration of 60 min. The findings revealed that RBD PK oil exhibits better anti-friction and anti-wear performance compared to commercial mineral oil (SAE 40). Besides, coefficient of friction is less dependent on ZDDP concentration, but anti-wear ability is dependent on the ZDDP additive concentration. ZDDP additive acts as a good anti-wear and antioxidant additive in RBD palm kernel.

No abstract

Abstract. The e ects of zinc dialkyl dithiophosphate (ZDDP) concentration on tribological behavior of the Re ned, Bleached, and Deodorized (RBD) palm kernel were analyzed using a pin-on-disk tribotester. RBD palm kernel was selected as a base lubricant due to its availability, low price, renewability, and being environmentally friendly. Commercial mineral oil (SAE 40) was used for comparison. The tests were performed at 2.5 m/s sliding speed under 9.8 N applied load for 60 minutes at 25 C temperature ( 2 C). Worn surface of the pin was measured by the optical microscope to understand the wear mechanism involved. Compared with SAE 40, experimental results show that the addition of 5 wt% of ZDDP reduced the coe cient of friction to 21%. However, the anti-wear property was still lower, approximately at 23%. Besides, the tribological behavior of RBD palm kernel was improved with ZDDP additive concentration above 1 wt% where the best performance was at 5 wt%. At this concentration level, ZDDP additive was able to protect the surface against wear and oxidation and, at the same time, reduce coe cient of friction, wear rate, and surface roughness values.

No abstract