Experimental Investigation of Tribological Performance of Locally Synthesized Biolubricants for Mechatronic System Actuators in Tropical Environments

Lubricants are critical to the reliable performance of actuators, bearings, and gear trains within mechatronic systems deployed in tropical environmental conditions, yet Nigeria remains almost entirely dependent on imported synthetic petroleum-based lubricants for industrial applications. This study presents an experimental investigation of the tribological performance of biolubricants synthesized from locally abundant Nigerian plant oil feedstocks, specifically neem oil, palm kernel oil, and rubber seed oil, for application in mechatronic system actuator components. Base oil synthesis and viscosity modification were conducted using oleochemical esterification processes, and lubricant formulations were characterized for kinematic viscosity, viscosity index, flash point, pour point, and oxidation stability following ASTM standard test methods. Tribological performance, specifically friction coefficient and wear rate, was evaluated on a pin-on-disc tribometer under sliding contact conditions representative of linear actuator guide rail interfaces. Testing temperatures ranged from 25 to 80 degrees Celsius to cover the actuator operating temperature range in tropical industrial environments. Neem oil-derived biolubricant exhibited a viscosity index of 168, superior to the commercial mineral oil reference at 98, and achieved 12 percent lower steady-state friction coefficient under boundary lubrication conditions. Palm kernel-based lubricant demonstrated the lowest wear rate at 8.4 times 10 to the power of negative 14 cubic metres per Newton-metre. The study confirms that Nigerian plant oil-derived biolubricants can achieve tribological performance comparable to imported synthetic lubricants for mechatronic actuator applications in tropical deployment contexts. Keywords: biolubricant, tribology, actuator, plant oil, tropical environment