Environmental aspects have a major impact on the application of technical products and decide about their success. Especially, with regard to hydraulic systems, these aspects can be fulfilled by the use of environmentally friendly fluids, based on synthetic esters. But the fluid’s properties strongly differ from the ones of the well-known mineral oil based fluids. Therefore, a profound knowledge of the fluid’s properties and their interaction with hydraulic components is essential for a successful usage of these fluids in hydraulic systems and moreover the basis of the development of a new generation of fluids which is going to take place within a research program at the University of Aachen. There, new environmentally friendly fluids are developed and tested in tribosystems applying new surface coated materials. Aim is to transfer important tribological features from fluids onto these base materials. Taking this route certain additives are no longer required and the missing characteristics have to be taken on by specially coated materials.
Therefore, analysis of the properties of synthetic esters, their change due to usage and the interaction with specially coated materials have been carried out. Moreover, a test facility will be presented which is able to do both ageing the fluid to analyze its ageing behavior and testing the fluid’s tribological properties. Besides the presentation of results with respect to the subject ageing of esters also results with respect to the influence of ageing on the tribological fluid properties will be shown.