Environmentally adapted lubricants properties and performance

Abstract: The lubricants of the future have to be more environmentally adapted, show a higher level of performance, and give a lower total life cycle cost (LCC) than the lubricants that are used today. One way to be able to produce, choose and formulate these lubricants is to have good knowledge about the properties of the base fluids and their additive response. The base fluid properties can be divided into four different groups, i.e. physical, chemical, film formation properties and additive response. This thesis is based on the results from the Swedish HiMeC research project "Environmentally adapted lubricants for high performance components". A number of different environmentally adapted ester fluids, suitable for formulation of environmentally adapted lubricants were investigated according to properties, molecular structure and film formation capability. I t was found that both thermal conductivity and specific heat capacity are high for the esters compared to mineral fluids. There is a strong correlation between the number of carboxylate groups and the thermal conductivity. The film formation capability was investigated by the use of optical interferometry in a ball and disc apparatus. A new model for measuring the running in performance of mechanical components was developed. The tests are run un-accelerated, with the same contact pressure and speed as the real applications they represent. The method is based on a tribotest and exact measurement of the surface topography at the exact same spot before and after the test. The most interesting parameters to monitor were found to be Rdq and Rpk. It was found that even very small changes at the uppermost parts of the topography can be measured and monitored whit this method. The additive response for both traditional anti wear additives and specially designed more polar additives where studied. The test where performed at Iwate University in Japan. A modified Falex pin and vee block tribotest machine where used. It was found that the new type of additives is efficient but further research is needed to be able to formulate fluid based on this chemistry. When putting all together, it could be seen that it will be possible to tailor make base fluids with suitable properties and additivate them with the correct additives for the task they should perform. That will make it possible to achieve better results than the fluids used to day in both environmental and performance aspects.