On the Tribological and Oxidation Study of Xanthophylls as Natural Additives in Castor Oil for Green Lubrication.

The present study focuses on an introductory analysis of the use of three xanthophylls as additives for green lubricant applications. For this purpose, the additives were characterized by FTIR and H-NMR techniques, and the bio-lubricants were described by their physical properties. The effect of the natural compounds on the friction and wear properties of bio-lubricants were evaluated by sliding friction tests under boundary conditions, as confirmed by an analysis of the lubricating film thickness.