The invention relates to thermochemical treatment of metal products, in particular relates to the technology of applying protective anti-corrosion coatings, which may be used for applying zinc-based thermodiffusion coatings (TDC coatings) on parts of different shapes, preferably on steel pipes of oilfield assortment, couplings, as well as fasteners and other products. A method of the invention relates to application of a thermodiffusion zinc-based coating to steel pipes, and comprises the steps of loading the pipes, a saturating mixture containing two-component zinc powder, activator and flux into the container; hermetically closing the container; vacuuming; filling the container cavity with non-oxidizing gas; heating and maintaining the container at a predetermined temperature; subsequent cooling the container and removing the pipes, characterized in that the first component of the two-component zinc powder having needle-shaped particles of 3-8 microns in size is loaded into the internal cavity of the pipes, and a second component of two-component zinc powder having spherical particles of 8-25 microns in size is loaded directly into container, and exposure being carried out at a temperature of 300-425? C., while a flux of one or more tertiary amines is introduced into the saturating mixture in an amount of 0.1-1.0 mas %; a filler containing one or more components selected from the group consisting of silica, wollastonite, carbon black, aluminum oxide and copper alloys, in the following ratio components in mass %: flux 0.1-1.0; filler 25-45; two-component powder zinc-the rest. Also claimed is a steel pipe having a hollow body with thermodiffusion zinc-based coating, characterized in that the coating is obtained using the method described above. The technical result of the invention is achieved by reducing the duration of exposure of the pipes in the temperature range of the thermodiffusion process when obtaining the coatings of a given thickness with improved corrosion resistance durability, uniformity and density of the coating over the entire surface of the pipe, as well as reducing the energy costs and increasing productivity, while ensuring high strength of pipes processed by the present method.

The invention relates to thermochemical treatment of metal products, in particular relates to the technology of applying protective anti-corrosion coatings, which may be used for applying zinc-based thermodiffusion coatings (TDC coatings) on parts of different shapes, preferably on steel pipes of oilfield assortment, couplings, as well as fasteners and other products. A method of the invention relates to application of a thermodiffusion zinc-based coating to steel pipes, and comprises the steps of loading the pipes, a saturating mixture containing two-component zinc powder, activator and flux into the container; hermetically closing the container; vacuuming; filling the container cavity with non-oxidizing gas; heating and maintaining the container at a predetermined temperature; subsequent cooling the container and removing the pipes, characterized in that the first component of the two-component zinc powder having needle-shaped particles of 3-8 microns in size is loaded into the internal cavity of the pipes, and a second component of two-component zinc powder having spherical particles of 8-25 microns in size is loaded directly into container, and exposure being carried out at a temperature of 300-425? C., while a flux of one or more tertiary amines is introduced into the saturating mixture in an amount of 0.1-1.0 mas %; a filler containing one or more components selected from the group consisting of silica, wollastonite, carbon black, aluminum oxide and copper alloys, in the following ratio components in mass %: flux 0.1-1.0; filler 25-45; two-component powder zinc-the rest. Also claimed is a steel pipe having a hollow body with thermodiffusion zinc-based coating, characterized in that the coating is obtained using the method described above. The technical result of the invention is achieved by reducing the duration of exposure of the pipes in the temperature range of the thermodiffusion process when obtaining the coatings of a given thickness with improved corrosion resistance durability, uniformity and density of the coating over the entire surface of the pipe, as well as reducing the energy costs and increasing productivity, while ensuring high strength of pipes processed by the present method.

A method of removing contaminants from a surface of a gas turbine engine component protected by a diffusion coating that comprises an additive layer on the surface of the component and a diffusion zone in the surface of the component. The method includes subjecting the surface containing contaminants to laser beam pulses to remove contaminants from the component such that contaminants on the surface of the component are removed without damaging or removing the diffusion zone of the diffusion coating. Methods for controlled removal of at least a portion of a thickness of a diffusion coating from a coated superalloy component are also provided.

A method of removing contaminants from a surface of a gas turbine engine component protected by a diffusion coating that comprises an additive layer on the surface of the component and a diffusion zone in the surface of the component. The method includes subjecting the surface containing contaminants to laser beam pulses to remove contaminants from the component such that contaminants on the surface of the component are removed without damaging or removing the diffusion zone of the diffusion coating. Methods for controlled removal of at least a portion of a thickness of a diffusion coating from a coated superalloy component are also provided.

A method of removing contaminants from a surface of a gas turbine engine component protected by a diffusion coating that comprises an additive layer on the surface of the component and a diffusion zone in the surface of the component. The method includes subjecting the surface containing contaminants to laser beam pulses to remove contaminants from the component such that contaminants on the surface of the component are removed without damaging or removing the diffusion zone of the diffusion coating. Methods for controlled removal of at least a portion of a thickness of a diffusion coating from a coated superalloy component are also provided.

A steel sheet for a container includes: a steel sheet; a coated layer which contains Ni and is provided as an upper layer of the steel sheet; and a chemical treatment layer which is provided as an upper layer of the coated layer, and contains a Zr compound in an amount of 3.0 to 30.0 mg/m.sup.2 in terms of Zr metal, and a Mg compound in an amount of 0.50 to 5.00 mg/m.sup.2 in terms of Mg metal, in which the coated layer is one of the group consisting of a Ni coated layer which contains Ni in amount of 10 to 1000 mg/m.sup.2 in terms of Ni metal, and a composite coated layer which contains Ni in an amount of 5 to 150 mg/m.sup.2 in terms of Ni metal and Sn in an amount of 300 to 3000 mg/m.sup.2 in terms of Sn metal, and has an island-shaped Sn coated layer formed on an FeNiSn alloy layer.

A process for forming a diffusion coating on a substrate is disclosed, including preparing a slurry including a donor metal powder, an activator powder, and a binder, and applying the slurry to the substrate. The slurry is dried on the substrate, forming a slurry layer on the substrate. A covering composition is applied over the slurry layer, and the covering composition is dried, forming at least one covering layer enclosing the slurry layer against the substrate. The slurry layer and the at least one covering layer are heated to form the diffusion coating on the substrate, the diffusion coating including an additive layer and an interdiffusion zone disposed between the substrate and the additive layer.

A process for forming a diffusion coating on a substrate is disclosed, including preparing a slurry including a donor metal powder, an activator powder, and a binder, and applying the slurry to the substrate. The slurry is dried on the substrate, forming a slurry layer on the substrate. A covering composition is applied over the slurry layer, and the covering composition is dried, forming at least one covering layer enclosing the slurry layer against the substrate. The slurry layer and the at least one covering layer are heated to form the diffusion coating on the substrate, the diffusion coating including an additive layer and an interdiffusion zone disposed between the substrate and the additive layer.

The present invention is directed to coating compositions for forming diffusion coatings on metal-based substrates. The coating compositions may include a metal powder, an inorganic salt, an activator, and a binder. The present invention is also directed to processes for forming diffusion coatings on metal-based substrates using the disclosed coating compositions.

The present invention is directed to coating compositions for forming diffusion coatings on metal-based substrates. The coating compositions may include a metal powder, an inorganic salt, an activator, and a binder. The present invention is also directed to processes for forming diffusion coatings on metal-based substrates using the disclosed coating compositions.