The present disclosure relates to polysiloxanes, processes for preparing polysiloxanes, and hydraulic fluids comprising polysiloxanes. This disclosure also relates to hydraulic fluids comprising one or more polysiloxane compounds and diphosphonate compounds, and to the use of diphosphonate compounds in hydraulic fluids or as additives or components in various compositions, for example to provide fire retardant properties to a fluid or composition. This disclosure also relates to use of the compositions as hydraulic fluids, which may be used in various machines, vehicles and craft, including aircraft.

The present disclosure relates to methods, systems, hydraulic fluids and additives for reducing the rate of surface current degradation for components in a hydraulic system, wherein the hydraulic system is exposed to phosphate-ester-based hydraulic fluid.

The present disclosure relates to methods, systems, hydraulic fluids and additives for reducing the rate of surface current degradation for components in a hydraulic system, wherein the hydraulic system is exposed to phosphate-ester-based hydraulic fluid.

In examples, a microelectromechanical systems (MEMS) device comprises a moveable element configured to contact a portion of a surface, and a film formed of a self-assembled lubricant, the lubricant comprising a compound having (i) an oxoacid moiety and (ii) a hydrophobic moiety with an A value of equal to or greater than about 3 kilocalories/mole on the portion of the surface.