Additives for Environmentally Adapted Lubricants - Friction and Wear Protection

Five different anti-wear additives, suitable for the formulation of environmentally adapted hydraulic fluids were tested, both commercially available and newly developed. The used base fluid was a high performance saturated complex ester. The formulated fluids' performance was evaluated through the use of an assembled pin & vee block in a modified Falex wear tester according to wear and frictional behaviour. The combinations of tested materials were steel-steel and bronze-steel tribopairs. The friction, wear scar volume and visual appearance both inside and outside the wear scar were studied. Some of the tested combinations gave unwanted performance, such as high friction, large wear and etching damages, whereas others gave good performance. It was found that the new additives showed promising results for formulation of environmentally adapted lubricants based on saturated complex esters. Further investigations will look closer at the chemical composition of the formed tribofilms with the use of surface sensitive analysis technology