Conversion of used engine oils from agricultural machinery into colloidal graphite greases enhanced lubricating greases

The article examines the development of a stable lubricant enhanced with colloidal graphite, utilizing recycled ۱۵W۴۰ diesel engine oil thickened with calcium soap. The study reveals that increasing the graphite concentration results in a gradual rise in water content, while the amount of thickener remains unchanged. Furthermore, higher graphite levels lead to a reduction in penetration values, decreasing from ۴۴۰ units to ۳۱۰ units. This suggests an improvement in grease consistency and stiffness. The dropping point also shows notable changes, increasing from ۷۹°C to ۸۸°C at a graphite concentration of ۱۵۰ ppm, before declining to ۸۱°C with further graphite additions. Regarding anti-wear performance, the smallest wear scar diameter is observed at the same ۱۵۰ ppm concentration, measuring ۰.۲۱۵ mm—۲۵.۱% smaller than that of the control sample.

کلیدواژه ها:

processing of agricultural waste ، colloidal graphite ، nanographite ، consistent lubricants ، electrochemical exfoliation