Spectroscopic analysis of perfluoropolyether lubricant degradation during boundary lubrication

The degradation of a branched perfluor polyether (PFPE) under boundary hibrication conditions was studied using micro-Fourter transform infrared spectroscopy and micro-Raman spectroscopy. Stainless steel (440C) dises coated with thin (600A), uniform films of the PFPE were tested in a ball-on-dise apparatus until various leveis of friction coefficient were attained. Disc were then examined using the above techniques When the friction coefficient surpassed the value obtained with an unlubricated control, the lubricant film had either been physically displaced or parnally transformed into a frication polymer Infrared analysts of this friction polymer indicated the presence of a polymeric fluorinated acid species (RCOOH). Raman spectroscopy indicated the presence of a graphitic amorphous carbon in the wear track and in the friction polymer, Some reaction mechanisms are suggested to explain the results.