Centre Stephanois De Recherches Mecaniques Hydromecanique Et Frottement

Pascal Fort

Jean-Paul Terrat

Coating for conferring good friction properties upon a substrate and comprising a non-equilibrium alloy of chromium and nitrogen. The alloy comprises, per one hundred atoms, from 87 to 68 atoms of chromium and from 13 to 32 atoms of nitrogen and two phases, a cubic microcrystalline chromium phase containing included nitrogen and a quadratic chromium nitride phase with a stoichiometric deficient nitrogen content relative to the Cr.sub.2 N nitride. The ratio of the quadratic nitride lattice parameters is between 1.02 and 1.5. This quadratic nitride was previously unknown and probably can exist only in association with chromium. It resists wear up to five times better than known single-phase chromium-nitrogen alloys and is free of the inherent fragility of two-phase alloys containing hexagonal Cr.sub.2 N nitride. The coatings are obtained by magnetron cathode sputtering of chromium with a nitrogen partial presure in a rare gas atmosphere between a maximum and a minimum determined experimentally.

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Villefranche De Rouergue, France

Pascal Fort