Process for the boronizing of pieces made of metal or cermet
AssigneeAssociation pour la Recherche et le Developpement des Methodes et Processus Industriels A.R.M.I.N.E.S.
InventorsFrancois H. J. Thevenot, Patrice M. V. Goeuriot, Julian H. Driver, Jean-Paul R. Lebrun
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Abstract
The invention relates to a process and apparatus for boronizing pieces made of metal or cermet and to surface-boronized pieces. The pieces are placed in a chamber at between 850.degree. and 1,150.degree. C. and they are subjected, in the presence of boron carbide, to a gaseous stream of trifluoroboroxole (BOF).sub.3. The boron carbide is advantageously pulverulent and out of contact with the pieces to be boronized.
Claims15
Process for the treatment by boronising pieces of a material selected from the group consisting of alloys of Fe, Ni and Co and cermets, said process comprising heating said pieces to an operating temperature in the range of 850.degree. to 1,150.degree. C. while in the presence of a solid boronising agent, and activating the boronising by simultaneously subjecting the pieces to the contact action of a stream of a gaseous fluorine-containing agent containing trifluoroboroxole (BOF).sub.3, under predetermined pressure and temperature conditions.
Process for the treatment by boronising of pieces of a material selected from the group consistng of alloys of Fe, Ni and Co and cermets, said process comprising heating the articles to an operating temperature in the range of 850.degree. to 1,150.degree. C. while in the presence of a solid boronising agent, and activating the boronising by simultaneously subjecting the pieces to the contact action of a stream of a gaseous fluorine-containing agent, under predetermined conditions of pressure and temperature, wherein the gaseous fluorine-containing agent contains trifluoroboroxole (BOF).sub.3, said gaseous fluorine-containing agent produced by passing BF.sub.3 or a gaseous mixture containing BF.sub.3 through a pulverulent mass of mineral oxides free of cationic impurities, said oxides selected from the group consistng of simple oxides of silicon and complex oxides of silicon, aluminum and magnesium, the pulverulent mass being heated to a temperature of at least 450.degree. C.
Dependencies are inferred from the claim text.