WEAR-REDUCING SURFACE-FILMS FORMED BY A FLUORINATED SULFONAMIDE ADDITIVE IN A CHLOROTRIFLUOROETHYLENE-BASED FLUID

Chlorotrifluoroethylene (CTFE) oligomer is the base fluid for MIL-H-53 119, a nonflammable synthetic hydraulic fluid. The MIL-H-53119 formula tion includes an anticorrosion additive and a fluorinated sulfonamide antiwear additive. The sulfonamide additive reduced the friction and w ear between alloy steel specimens during rubbing. The wear-reducing me chanisms of this additive in CTFE were studied using a reciprocating t ribometer and various surface analysis techniques. The additive increa sed the iron chloride-to-oxide concentration ratio within the surface film. Since the additive is chlorine-free, it must have increased the surface interactions between the CTFE fluid and the steel substrate to form chloride-rich films.