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 for coating a heat engine part, particularly a turbo-machine part made of a superalloy and adapted for use in aeronautical applications, comprises electrophoretically depositing a metallic structure of cellular form with uniformly disposed cells of predetermined size. The deposition is performed using an electrophoresis bath containing methanol, aluminum chloride as an electrolyte, and a powder containing Cr, Al, Y, Ta and Ni. The cellular metallic structure is consolidated by a sintering treatment, which may be reactive, or metallization, preferably in the vapor phase, and the coating is completed by applying a ceramic material by plasma spraying.

A method producing a coating on a substrate by aluminizing, chromizing or siliconizing the substrate, and depositing on the coated substrate by electrolytic or electroless deposition a metal matrix M.sub.1 from a bath containing particles of CrAlM.sub.2 to co-deposit the particles with the matrix as M.sub.1 CrAlM.sub.2, where M.sub.1 is Ni, Co or Fe or two or all of these elements and M.sub.2 is Y, Si, Ti, Hf, Ga, Nb, Mn, Pt, a rare earth element or two or more of these elements. Preferably, the method includes platinum aluminizing of the substrate. Heat treatments may be incorporated before and after deposition of the M.sub.1 CrAlM.sub.2. The deposition of the M.sub.1 CrAlM.sub.2 is carried out at a current density of less than 5 mA per square centimeter. Preferably, the deposition forms a M.sub.1 CrAlM.sub.2 layer less than 50 microns thick, and occurs at a bath loading of less than 40 grams per liter of the particles. In a preferred embodiment, the particle size distribution in the plating bath is 25 percent between 15 and 12 microns, 45 percent between 12 and 10 microns and 30 percent less than 10 microns. The method is particularly useful for coating a gas turbine part.

A method of producing a coating on a substrate by electrolytically co-depositing a metal matrix M.sub.1 and particles of CrAlM.sub.2, where M.sub.1 is Ni, Co or Fe or two or all of these elements and M.sub.2 is Y, Si, Ti, Hf, Ga, Nb, Mn, Pt, a rare earth element or two or more of these elements. The co-deposition is carried out at a current density of less than 5mA per square centimeter. Preferably, the co-deposition forms a layer less than 50 microns thick, and occurs at a bath loading of less than 40 grams per liter of the particles. In a preferred embodiment, the particle size distribution in the plating bath is 25 percent between 15 and 12 microns, 45 percent between 12 and 10 microns and 30 percent less than 10 microns. The method is particularly useful for coating a gas turbine part.

The present invention provides a method to coat an article using a plating process, either electroless or electrolytic, whereby nickel is plated on the article using a solution that includes a suspension of powders or containing one or more of the following elements: Ni, Cr, Al, Zr, Hf, Ti, Ta, Si, Ca, Fe, Y and Ga. Optionally, the coating is then heat treated at a temperature above about 1600.degree. F. for an effective amount of time to allow to homogenize the coating by allowing effective interdiffusion between the species. The level of aluminum may be altered to produce a coating of the predominantly .beta. phase of the NiAl alloy composition. Optionally, a TBC layer is applied over the predominantly .beta. phase NiAl alloy composition metallic bond coat.