FRICTION AND WEAR OF THE FILM FORMED IN THE IMMERSION TEST OF OIL CONTAINING ANTIWEAR AND EXTREME-PRESSURE ADDITIVES

The oil immersion test is a useful method to investigate the interacti on between steel-bearing and oil additives. In this work, oil immersio n tests of steel blocks with sulfurized olefin (SO), dibutyl phosphite (DBP), and the combination of SO and DBP in various weight ratios in liquid paraffin were conducted at a temperature of 180 degrees C for a test duration of 60 min. The chemical composition of the film formed was examined using both X-ray photoelectron spectroscopy and Auger ele ctron spectroscopy. The friction coefficient and wear life of the film s formed in the oil immersion tests were evaluated using a one-way rec iprocating friction tester under dry friction conditions against a ste el ball at room temperature. The performance of the liquid paraffin co ntaining SO, DBP or the combination of SO and DBP was also investigate d with a four-ball wear tester. Results indicate that with the S/P wei ght ratio at 55, a lower friction coefficient and longer wear life of the film formed in the immersion test can be observed. Test results de monstrate that the wear life of the film formed in the oil immersion t ests are in good agreement with the wear results of the conventional f our-ball wear test.