AN ACCELERATED AGING TEST FOR ANTIWEAR HYDRAULIC OILS

The design of modern hydraulic systems essentially includes sophistica ted servo-controlled mechanisms coupled with fine filters. For the smo oth operation of these systems, new formulations of antiwear (AW) hydr aulic oils have been developed incorporating thermally stable zinc dia lkyldithiophosphate (ZDDP). It has been established that problem free performance of these oils largely depends upon the controlled decompos ition of ZDDPs and the dispersion of the generated sludge, avoiding th e blockage of the fine filters. Through a simulated aging test, the be havior of various AW hydraulic oils with respect to their thermal stab ility, AW performance, and particle build-up has been studied. This pa per depicts the details of this new aging test and describes the test results obtained on different types of AW hydraulic oils.