| Friction and wear experiments were carried out on the test couples consisting of hastelloy alloy x (pin)-hastelloy alloy x (disc), hastelloy alloy x-tool steel, tool steel-hastelloy alloy x, nickel-nickel, iron-iron, aluminum-tool steel, Al-0.5% Si-tool steel, Al-0.5% Ge-tool steel, Al-0.5% Sb-tool steel, Zn-0.5% Te-tool steel, Zn-tool steel in an atmospheric air environment and in a mild vacuum environment ((DBLTURN)50 millitorr).;By Auger Electron Spectroscopy with ion sputtering it was found that the solute element (silicon, germanium, antimony, tellurium) segregated on the surface of the samples which showed extremely low wear rates in a mild vacuum environment. Also it was found that the oxide thickness on these couples after the test was smaller than that of the couples which were tested in an air environment.;Thus it is suggested that the segregation of the solute element and the formation of the strengthened compacted oxide film on the surface are the main reasons of the null wear rate. The oxide films which contain group 4 elements (silicon, germanium), at group 3 element (Al) and a group 5 element (Sb) together, or a group 2 element (Zn) and a group 6 element (Te) together are thin, but very strong, and adherent to the base metal. Thus, the similar condition of the passivity in corrosion occurs; the oxide film protects the base metal from the wear resulting in passivation of wear.;Hastelloy alloy x (pin)-tool steel (disc), Al-0.5% Si-tool steel, Al-0.5% Ge-tool steel, Al-0.5% Sb-tool steel, Zn-0.5% Te-tool steel couples showed extremely low wear rate or no wear rate and very low friction coefficient at sliding speed of rpm 120 (=0.16 mm/sec for track diameter 25.4 mm) and below a critical load ((DBLTURN)8.9 N) in a mild vacuum environment. This extremely low wear rate (null wear rate) was 10('2) (TURN) 10('4) times lower than the normal wear rate in an atmospheric air environment. |
