| abstract |
Disclosed are phosphate ester base fluids and aircraft hydraulic fluids containing mixed n-butyl/isobutyl phosphate ester components. The disclosed aircraft hydraulic fluids contain from about 30 to about 95 weight percent, based on the total weight of the fluid, of n-butyl diisobutyl phosphate or di-n-butyl isobutyl phosphate or a mixture thereof; from 0 to about 15 weight percent, based on the total weight of the fluid, of one or more triaryl phosphates; and an effective amount of a viscosity index improver, an acid control additive and an erosion inhibitor. |