Centre Stephanois De Recherches Mecaniques Hydromecanique Et Frottement

Centre Stephanois De Recherches Mecanique Hydromecanique Et Frottement

Centre Stephanois De Recherches Mecanmiques Hydromecanique Et Frottement

Antoine Gaucher

Jean-Paul Terrat

Andre Aubert

Gerard Guilhot

Jacques Chevallier

Bernard Zabinski

By cathode sputtering in a reactive environment, a coating of a solid solon of chromium and an element such as nitrogen, carbon, phosphorus, boron or silicon is deposited. The content of the above element is higher than the saturation limit of the solid solution in chromium. It ranges between T.sub.m =0.2% and T.sub.M =3% by weight for carbon and between T.sub.m =0.04% and T.sub.M =3.5% by weight for nitrogen.

Chromium coating with high hardness capable of resisting wear, strain

A process for the production of an aqueous lubricant composition free of oil including water and at least one metallic carboxylate, wherein the anionic is at least one saturated linear organic radical containing at least 12 carbon atoms and the cationic is at least one bivalent or trivalent metal having an electro-chemical oxidation-reduction potential greater than -0.7 volts. The process includes mixing of two mother solutions. The first mother solution is an aqueous solution of at least one alkali metal carboxylate soluble in water wherein the anionic is at least one saturated linear organic radical with at least 12 carbon atoms. The second mother solution is an aqueous solution of at least one metallic salt whereof the anionic is selected from the group consisting of hydroxide, chloride, sulphate, nitrate or phosphate ions and whereof the cationic is at least one bivalent or trivalent metal having an electro-chemical oxidation reduction potential greater than -0.70 volts.

Aqueous lubricating composition and process of manufacturing same

A method of treating a part which contains titanium in its outer surface luding the steps of removing a portion of the natural oxide layer, placing the part in an enclosure, evacuating the enclosure, isolating the evacuated enclosure, and introducing oxygen in an amount ranging from 10.sup.-3 to 2.55 milligrams for each square centimeter of total outer part surface area, and heating to a temperature from 450.degree. C. to 880.degree. C.

Method for treating parts made of titanium or titanium alloy, and parts

The invention relates to a method of maintaining at very low values the portions of cyanides in molten-salt baths of the kind in which the main active principle is the cyanate anion CNO.sup.-, the method comprising essentially the steps of conjointly providing in the salt bath at least one sulphurized element in a quantity such that the proportion of the sulphur element in the bath is between 0.001 and 0.1 % of the weight of said bath, and introducing periodically or continuously into the bath at least one substance comprising at least one carbonyl group = C = O in its chemical formula, in a quantity such that it corresponds to a weight of between 1 and 25 grams of CO per kg. of bath and per 24 hours maintenance at the bath working temperature of between 480.degree. and 650.degree. C. The substance introducing the carbonyl group may also constitute a regenerating agent for the cyanate anion and can advantageously be obtained by baking carbamide for 3 to 10 hours at a temperature of between 150.degree. and 450.degree. C. The bath may be homogenized by agitation means including insufflation of air. The invention is especially applicable to the nitridation of mechanical parts in heat-treatment salt-baths.

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Saint-Etienne, France

Antoine Gaucher