PERTANIKA JOURNAL OF SCIENCE AND TECHNOLOGY

Machining is essential in manufacturing for shaping materials by removing excess through contact between the tool and workpiece. However, dry machining generates significant heat and cutting forces, leading to tool degradation and surface imperfections. While flood cooling helps address these issues, it presents environmental and health concerns due to large volumes of fluid and harmful chemical additives. Minimum Quantity Lubrication (MQL) offers a greener alternative by applying only the minimum amount of lubricant directly to the cutting area. Still, it frequently proves insufficient in handling difficult-to-cut materials like nickel-based alloys, owing to poor heat removal and lubrication. This study investigates enhancing MQL using silicon dioxide (SiO₂) nanoparticles in vegetable oil-based formulations, creating an improved nanolubricant system (NMQL). The volume concentrations of five different percentages were tested: 0.01%, 0.03%, 0.05%, 0.07%, and 0.1 % of SiO₂ biodegradable nanolubricant. Stability was evaluated through visual sedimentation observation, UV-visible measurements, and zeta potential analysis. Some slight sedimentation occurrences through visual observations indicated nanolubricant stability even after 10 days. UV-visible stability was measured at a 0.1% volume concentration, showing a linear correlation adhering to Beer-Lambert law principles. The most stable nanolubricant resulted from 2 hours of sonication at a 349 nm wavelength, exhibiting an excellent zeta potential stability of 98.3 mV. Thermophysical testing revealed that 0.1% concentration produced the highest dynamic viscosity compared to the base oil. In the tribological evaluation, the 0.07% concentration exhibited the lowest coefficient of friction and wear scar diameter. Overall, biodegradable nanolubricants serve as a potential for Minimum Quantity Lubrication (MQL) machining.