Tribological properties of biodegradable nano-lubricant

Abstract

The biodegradable or vegetable oil possess good chemical properties competitive with mineral oil which can used as alternative lubricant. However, the vegetable oil has poor performance of tribological characteristics at high temperature and oxidation which causes the vegetable lubricant not used widely in industrial sector. To optimize lubrication, the vegetable oil can be mixed with hybrid additives. In this paper, RBD palm olein and soybean oil was mixed with single and hybrid additives which has been tested to determine its lubricating properties. The additives which has been used for the study was zddp and copper oxide nanoparticles. The mixing percentage of zddp has been fixed with 1% optimum whereas the copper oxide nanoparticles varies from 0.75% to 1% of the total mass. Testing has been conducted using fourball tribotester based on ASTM D4172 standard condition. The result shows that formulated palm olein lubricant with hybrid additive with zddp and CuO nanoparticles at 0.75% and 1% respectively provided 54.6% of WSD reduction, 29.2% COF reduction and smooth surface roughness compared with base RDB palm olein and soybean oil. However, in term of WSD and surface roughness, the mineral lubricant possesses better performance expect COF value of hybrid additive lubricant possess better value. From this results, it can be concluded that the performance of vegetable lubricant could be better enhanced with hybrid additives and its tribological characteristics competitive with conventional mineral lubricant.