Abstract: A method for thermochemically treating a part while masking a portion and corresponding mask are provided. The method includes the steps of providing a mask comprising a body with a seat, at least a deformable sealing washer located in the seat, and a tightening bushing, the body having a cavity, placing a first portion of the part in the cavity, a second portion of the part being located in a passage in the sealing washer, and a third portion of the part being located outside the mask, moving the tightening bushing to its tightened position so that the sealing washer is deformed and applied against the second portion of the part, and applying a thermochemical treatment to the third portion of the part.

Abstract: A method for thermochemically treating a part while masking a portion and corresponding mask are provided. The method includes the steps of providing a mask comprising a body with a seat, at least a deformable sealing washer located in the seat, and a tightening bushing, the body having a cavity, placing a first portion of the part in the cavity, a second portion of the part being located in a passage in the sealing washer, and a third portion of the part being located outside the mask, moving the tightening bushing to its tightened position so that the sealing washer is deformed and applied against the second portion of the part, and applying a thermochemical treatment to the third portion of the part.

Abstract: A surface treatment method in which a surface of a part (7) is contacted with at least one activated species. The activated species is obtained by activating a gaseous medium containing at least two of the following elements: carbon, nitrogen, boron and oxygen. Preferably, the activated species is a neutral excited CN species. The activated species brings at least one interstitial element to the metal part (7) surface which is borne and maintained at a temperature enabling the interstitial element to be diffused into a surface layer of the metal part (7).

Abstract: A process for reducing the coefficient of friction and the wear between a metal part and an organic polymer- or copolymer-based part, in an aqueous medium containing chlorides, characterized in that the organic polymer- or copolymer-based part is submitted to a surface treatment by ionic implantation of elements selected from nitrogen, argon, oxygen and carbon.

Abstract: The process with a view to imparting to the treated article a resistance to frictional wear, a corrosion resistance, and a color, is characterized according to the invention in that the surface of the article is subjected to a thermochemical pretreatment under electric plasma in a vessel under an atmosphere containing reactive species such as N.sub.2 and hydrogen, the reactive species diffusing into and precipitating in the metal matrix of the article to form a diffusion sublayer and in that a layer of carbon in vapor phase is deposited under electric plasma on the surface thus treated, in the same vessel, the composition of the atmosphere for the pretreatment being gradually modified, on the one hand, by the introduction of a hydrocarbon and/or of a silane in the gaseous state and, on the other hand, by progressive reduction of the partial pressures of the reactive species employed during the pretreatment, and the maintenance of the hydrocarbon atmosphere for the carbon deposition.

Abstract: The object of the present invention is a deposition process of a coating of the ceramic type based on carbides, nitrides, or carbonitrides of metallic elements such as Cr, V, Zr, W, Mo, Co, Mn, Ni, Hf, Ta, Ti, Nb and Fe in which the coating of the ceramic type is deposited at low temperature in the vapour phase on a metallic substrate from organo-metallic precursors wherein, prior to this deposition in the vapour phase and without subsequent placing in contact with an oxidizing and/or polluting atmosphere, a reactive ionic pickling is carried out in a reducing atmosphere.

Abstract: The object of the invention is a one-step deposition process of a coating of the ceramic type based on nitrides or carbonitrides of at least one metallic element selected from Cr, V, Zr, W, Mo, Co, Mn, Ni, Hf and Ta on a metallic or ceramic substrate, massive or obtained from fibres, by deposition in the vapor phase wherein a coating is deposited on the substrate by a chemical means at a pressure lower than 10 kPa at a temperature lower than 600.degree. C. and by using a system of precursors constituted simultaneously of:an organo-metallic precursor of the said metallic element selected from the organo-metallic compounds of the sandwich type of general formula:[Ar.sup.1 M Ar.sup.2.sub.n ]L.sub.x L'.sub.ya nitrogen precursor selected from ammonia and hydrazine.