Knowledge of the physical and chemical changes occuring in the bulk lubricant and the solid-lubricant interface is essential in order to control friction and wear. This program will employ spectroscopic techniques to study these physical and chemical chances under realistic conditions. Laser light scattering and vibrational spectroscopy will be used to investigate the micellization and oxidation phenomena in bulk oil,as a function of temperature, wear and anti-oxidation additives and oxygen pressure. The changes occurring at the interface will be followed both under static and dynamic conditions. Under static conditions attenuated total internal reflection IR spectroscopy will be used to monitor the adsorption-desorption, and reaction kinetics of the oil and the additives at the solid-lubricant interface. Analysis of the data will yield rate constants as well as chemical information about the alignment and binding of the lubricant molecules to the solid surface. The oxidation kinetics of the solid surface will be determined from an analysis of the vibrational bands due to the formation of metal oxides. Perhaps the most informative measurements will be obtained under realistic conditions with a diamond slider. Using single reflection FTIR and Raman scattering the chemical condition of the lubricant film and the solid surface will be measured in real time right behind the contact point as a function of load and temperature.
