Less-flammable phosphate ester hydraulic-system fluids replaced hydrocarbon fluids with the advent of commercial jet airplanes in the 1950s. A new problem then called "erosion" of the metering edges of servocontrol valves developed. This "erosion" was determined to be corrosion caused by the generation of electrokinetic streaming currents in the late 1960s. Subsequently it was found that ionically conducting antierosion additives (AEAs) added to the fluids eliminated the erosion problem. The valve erosion problem with phosphate ester fluids has subsequently been virtually eliminated. New experimental results and refined modeling show that the AEAs decrease the zeta potential and thus corrosion, mainly by specific adsorption and electrical double-layer compression, and that the previously proposed back-conduction is insufficient. The concepts described provide a background for investigating other unexplored instances of electrokinetic corrosion such as wear in lubricated systems and chemical polishing. (c) 2006 The Electrochemical Society.