Abstract
Synthetic oils and greases are used for space lubricant. So, it is important to know the performances of these lubricants. The base oil 815Z and 2001A and the greases 600EF, 601EF and 602EF with base oil 815Z and grease R2000 were considered as the test fluid in this study. The highest wear scar has found for base oil 815Z but it showed the lowest coefficient of friction, whereas greases 600EF, 601EF and 602EF showed lower wear scar and considerable friction coefficient Investigating these phenomena, authors found that the base oil 815Z contains the acetal group (-OCF_2O-). At high shear rate in EHL conjunction the viscosity was decreased by mechanical shear. Hydrogen fluoride occurred with the decomposition of acetal group. It increases the wear rate of the contact surfaces. But that decomposition does not occurred in the greases with base oil 815Z and showed better result as space lubricant.
