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AssigneeOffice National d'Etudes et de Recherches Aerospatiales
InventorsBenoît Girard, Marie-Pierre Bacos, Eric Berger, Pierre Josso
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The invention concerns a method wherein the substrate (5) to be coated is immersed in an autocatalytic chemical deposit bath (4), for example nickel, contained in a stainless steel vessel (1) and wherein can be optionally mixed a suspended MCrAlY alloy, so as to form a metal deposit (nickel) wherein are optionally included powder particles. The invention is characterised in that, to provide a prolonged operation of the bath, it consists in measuring with a voltmeter (8) the difference of potential between the substrate (5) and a reference electrode (6) immersed in the bath (4), and in imposing between the substrate (5) and the vessel (1) an electric current produced by a generator (10), said current being adjusted by a regulator (11) so as to maintain said potential difference at a selected value.
A method of forming a coating on a metallic substrate (5) by chemical deposition of at least one metal from ions of the said metal present in an autocatalytic bath (4) comprising a reducing agent contained in a vessel (1), with an electrically conductive surface connected to the positive pole of a current source (10), the negative pole of which is connected to the substrate, the method characterized in that the intensity of the current source is regulated in such a way as to maintain the potential of the substrate (5) between −1V and 0V with respect to the potential of a reference electrode (6) immersed in the bath, the potential of the reference electrode being equal to the redox potential of the at least one couple consisting of reduced metal and metal to be reduced complexed in the bath (4).
Dependencies are inferred from the claim text.