Document Type: Article
Faculty of Mechanical Engineering, Universiti Teknologi Malaysia, 81310 UTM Johor Bahru, Johor, Malaysia
The effects of zinc dialkyl dithiophosphate (ZDDP) concentration on tribological behavior of refined, bleached and deodorized (RBD) palm kernel were analyzed using a pin-on-disk tribotester. RBD palm kernel was selected as base lubricant due to its availability, low price, renewability and environmental friendly. Commercial mineral oil (SAE 40) was used for comparison. The tests were performed at 2.5 m/s of sliding speed under 9.8 N applied load for 60 minutes and temperature at 25 ( 2 ). Worn surface of the pin was measured by optical microscope to understand the wear mechanism involved. Experimental results showed that the addition of 5wt% of ZDDP has reduced the coefficient of friction to 21% compared with SAE 40. However, the anti-wear property was still lesser, approximately at 23%. Besides, the tribological behavior of RBD palm kernel was improved with ZDDP additive concentration above 1wt% where the best performance was at 5wt%. At this concentration level, ZDDP additive was able to protect the surface against wear and oxidation, and at the same time reduces coefficient of friction, wear rate and surface roughness values.