| Popis: |
The surfaces of tappet inserts subjected to lubricated, moving contact in a cam/tappet friction apparatus have been analyzed by IR reflection—absorption, X-ray photoelectron and Auger electron spectroscopies. The two lubricants used were similar fully formulated oils. One contained a soluble molybdenum friction modifier additive while the other did not. Thin inorganic films were formed across the contact area during the cam/tappet experiment. Regardless of the lubricant used, these films consisted of varying amounts of inorganic phosphates, sulfates, sulfides, and perhaps thiophosphates, with zinc and magnesium as cations. Molybdenum would also be a cation in the case of the friction modified oil. The films generated during the wear process differed in thickness, composition and surface coverage as a function of wear time, contact position and lubricant composition. The films formed by the friction modified oil were thinner and less continuous as compared with films formed from the unmodified oil. |
