New hydraulic biolubricants based on passion fruit and moringa oils and their epoxy

This study aimed to develop new hydraulic biolubricants based on vegetable oils epoxidized via performic acid, and to investigate their tribological behavior under conditions of boundary lubrication. The tribological performance of the developed lubricants was analyzed in an HFRR (high frequency reciprocating rig) apparatus. The coefficient of friction, obtained during the contact and the formation of the lubricating film, was measured. The characterizations were performed according to DIN 51524 norm (Part 2 HLP) and DIN 51517 norm (Part 3 CLP) standards. The wear was evaluated by optical and scanning electron microscopy (SEM). The results showed that adding extreme pressure (EP) and antiwear (AW) additives in fluids improves significantly the tribological properties. It was observed that the addition of EP and AW additives to in natura vegetable oils of passion fruit and moringa did not reduce the wear considerably. The biolubricants developed from passion fruit and moringa oils, modified via epoxidation, displayed satisfactory tribological properties being considered as potential lubricants, able to replace commercial mineral-based fluids. (C) 2015 Elsevier B.V. All rights reserved.