A method for coating a substrate includes forming a conversion coat layer, depositing a protective coat onto the protective coat onto the conversion coat, and depositing a corrosion resistant top coat onto the protective coat. The conversion coat layer is formed by applying a conversion coat onto the substrate. The protective coat is deposited using a first atomic layer deposition. The corrosion resistant top coat is deposited using a second atomic layer deposition. The conversion coat layer has a volatizing temperature, and the first atomic layer deposition is performed at a deposition temperature that is no greater than 1.3 times the volatizing temperature of the conversation coat layer, calculated in Kelvin.

A process for producing an ordered martensitic iron nitride powder that is suitable for use as a permanent magnetic material is provided. The process includes fabricating an iron alloy powder having a desired composition and uniformity; nitriding the iron alloy powder by contacting the material with a nitrogen source in a fluidized bed reactor to produce a nitride iron powder; transforming the nitride iron powder to a disordered martensitic phase; annealing the disordered martensitic phase to an ordered martensitic phase; and separating the ordered martensitic phase from the iron nitride powder to yield an ordered martensitic iron nitride powder.

A process for producing an ordered martensitic iron nitride powder that is suitable for use as a permanent magnetic material is provided. The process includes fabricating an iron alloy powder having a desired composition and uniformity; nitriding the iron alloy powder by contacting the material with a nitrogen source in a fluidized bed reactor to produce a nitride iron powder; transforming the nitride iron powder to a disordered martensitic phase; annealing the disordered martensitic phase to an ordered martensitic phase; and separating the ordered martensitic phase from the iron nitride powder to yield an ordered martensitic iron nitride powder.

Methods of forming an environmental barrier coating are disclosed. A method includes disposing a powder-based coating on a substrate, heat-treating the powder-based coating at a temperature greater than 800 C. and less than 1200 C. to form a porous coating that includes surface-connected pores, infiltrating at least some of the surface-connected pores of the porous coating with an infiltrant material to form an infiltrated coating, and sintering the infiltrated coating at a temperature greater than 1200 C. and less than 1500 C. to form the environmental barrier coating on the substrate.

Methods of forming an environmental barrier coating are disclosed. A method includes disposing a powder-based coating on a substrate, heat-treating the powder-based coating at a temperature greater than 800 C. and less than 1200 C. to form a porous coating that includes surface-connected pores, infiltrating at least some of the surface-connected pores of the porous coating with an infiltrant material to form an infiltrated coating, and sintering the infiltrated coating at a temperature greater than 1200 C. and less than 1500 C. to form the environmental barrier coating on the substrate.

An article formed of a metal alloy is covered at least partially with a metal hydride and a shell metal to form an assembly. Load is applied to the assembly and the assembly is heated. The shell metal deforms around the article and the metal hydride and forms a gas proof seal. The metal hydride thermally decomposes to form hydrogen gas. At least a portion of the hydrogen gas dissociates and moves as monoatomic hydrogen into the article. The metal alloy can be a zirconium metal alloy, the metal hydride can be a zirconium metal hydride, and the shell metal can be substantially copper.

An article formed of a metal alloy is covered at least partially with a metal hydride and a shell metal to form an assembly. Load is applied to the assembly and the assembly is heated. The shell metal deforms around the article and the metal hydride and forms a gas proof seal. The metal hydride thermally decomposes to form hydrogen gas. At least a portion of the hydrogen gas dissociates and moves as monoatomic hydrogen into the article. The metal alloy can be a zirconium metal alloy, the metal hydride can be a zirconium metal hydride, and the shell metal can be substantially copper.

A method can include coating a first surface of an additively manufactured article made of a base material with a coating material comprising at least two constituents, wherein a first constituent of the at least two constituents is configured to be at least partially transient liquid phase (TLP) diffused from the coating material into the base material at a first constituent diffusion temperature, and a second constituent of the at least two constituents is configured to not diffuse from the coating material at the first constituent diffusion temperature, heating the additively manufactured article to the first constituent diffusion temperature, TLP diffusing at least a portion of the first constituent from the coating and into the base material, leaving the second constituent of the coating material on the first surface, and forming a second surface that is smoother than the first surface.

Nitrogen (N) absorption and diffusion treatments are performed for the inner and/or outer surfaces of austenite stainless steel pipe materials in N gas atmosphere at temperatures near 1,100 C. to obtain nitrided stainless steel pipe materials having 0.251.7% (mass) of solid solution nitrogen (N) including a gradient structure formed within the pipe wall in which the concentration of solid solution N continuously decreases gradually from the surface. The solid solution N present in the gradient structure promotes short range ordering (SRO) of substitutional alloying elements leading to homogenization of distribution of alloying elements in the austenite phase, generating an extremely high proof strength (yield strength) about 3 times as high as that of conventional austenite stainless steel pipe materials and enhancing characteristic of anti-hydrogen gas embrittlement (anti-HGE) so as to be suitable for use in a high pressure hydrogen tank utilized in hydrogen cell vehicle (FCV) and a liquid hydrogen tank.

Nitrogen (N) absorption and diffusion treatments are performed for the inner and/or outer surfaces of austenite stainless steel pipe materials in N gas atmosphere at temperatures near 1,100 C. to obtain nitrided stainless steel pipe materials having 0.251.7% (mass) of solid solution nitrogen (N) including a gradient structure formed within the pipe wall in which the concentration of solid solution N continuously decreases gradually from the surface. The solid solution N present in the gradient structure promotes short range ordering (SRO) of substitutional alloying elements leading to homogenization of distribution of alloying elements in the austenite phase, generating an extremely high proof strength (yield strength) about 3 times as high as that of conventional austenite stainless steel pipe materials and enhancing characteristic of anti-hydrogen gas embrittlement (anti-HGE) so as to be suitable for use in a high pressure hydrogen tank utilized in hydrogen cell vehicle (FCV) and a liquid hydrogen tank.