A method of manufacturing a passivation film, which includes a passivation process in which a substrate on the surface of which at least one of germanium and molybdenum is contained is treated with a passivation gas containing an oxygen-containing compound, which is a compound containing an oxygen atom in the molecule, and hydrogen sulfide to form a passivation film containing a sulfur atom on the surface of the substrate. The concentration of the oxygen-containing compound in the passivation gas is from 0.001 mole ppm to less than 75 mole ppm.

A method of manufacturing a passivation film, which includes a passivation process in which a substrate on the surface of which at least one of germanium and molybdenum is contained is treated with a passivation gas containing an oxygen-containing compound, which is a compound containing an oxygen atom in the molecule, and hydrogen sulfide to form a passivation film containing a sulfur atom on the surface of the substrate. The concentration of the oxygen-containing compound in the passivation gas is from 0.001 mole ppm to less than 75 mole ppm.

A method for providing a surface finish to a metal part includes both diffusion hardening a metal surface to form a diffusion-hardened layer, and oxidizing the diffusion-hardened layer to create an oxide coating thereon. The diffusion-hardened layer can be harder than an internal region of the metal part and might be ceramic, and the oxide coating can have a color that is different from the metal or ceramic, the color being unachievable only by diffusion hardening or only by oxidizing. The metal can be titanium or titanium alloy, the diffusion hardening can include carburizing or nitriding, and the oxidizing can include electrochemical oxidization. The oxide layer thickness can be controlled via the amount of voltage applied during oxidation, with the oxide coating color being a function of thickness. An enhanced hardness profile can extend to a depth of at least 20 microns below the top of the oxide coating.

A method for providing a surface finish to a metal part includes both diffusion hardening a metal surface to form a diffusion-hardened layer, and oxidizing the diffusion-hardened layer to create an oxide coating thereon. The diffusion-hardened layer can be harder than an internal region of the metal part and might be ceramic, and the oxide coating can have a color that is different from the metal or ceramic, the color being unachievable only by diffusion hardening or only by oxidizing. The metal can be titanium or titanium alloy, the diffusion hardening can include carburizing or nitriding, and the oxidizing can include electrochemical oxidization. The oxide layer thickness can be controlled via the amount of voltage applied during oxidation, with the oxide coating color being a function of thickness. An enhanced hardness profile can extend to a depth of at least 20 microns below the top of the oxide coating.

A method of manufacturing a brake disc of heterogeneous materials, may include a disc device and a hub device formed in a cast-bonding manner using different materials, includes performing a first casting for casting the disc device using a grey cast-iron material, performing a preparation step by placing the disc device in a casting mold as an insert, performing a second casting for preparing a brake disc cast product by injecting molten aluminum alloy into the casting mold and casting the hub device to be cast-bonded to the disc device, and performing an oxynitriding process for forming an oxynitride layer by smoothing a surface of the brake disc cast product and performing heat treatment in a gaseous atmosphere at a temperature ranging from 425 to 500 C.

An adjustment interface inserted between a first part made of nickel or made of nickel alloy or made of cobalt-chromium alloy in relative motion with a second part made of nickel or made of nickel alloy or made of cobalt-chromium alloy. The interface includes a first adjustment layer on one of the two parts and has a composition that makes it possible, with the friction with the other part, to create a glaze-type layer. A second adjustment layer is deposited on the second part for cooperation with the first layer to act as a catalyst for the oxide formed by friction with the first layer. The first glaze layer of the interface improves the sliding of the parts under friction. The catalyst function provided by the second layer makes it possible to stabilize the oxide formed by friction and to thus ensure a lubrication function over an extended high-temperature range.

An adjustment interface inserted between a first part made of nickel or made of nickel alloy or made of cobalt-chromium alloy in relative motion with a second part made of nickel or made of nickel alloy or made of cobalt-chromium alloy. The interface includes a first adjustment layer on one of the two parts and has a composition that makes it possible, with the friction with the other part, to create a glaze-type layer. A second adjustment layer is deposited on the second part for cooperation with the first layer to act as a catalyst for the oxide formed by friction with the first layer. The first glaze layer of the interface improves the sliding of the parts under friction. The catalyst function provided by the second layer makes it possible to stabilize the oxide formed by friction and to thus ensure a lubrication function over an extended high-temperature range.

A method of forming a rotor includes isolating a bridge area of an electrical steel lamination. The bridge area is disposed between a first portion of the electrical steel lamination and a second portion of the electrical steel lamination that is adjacent to the first portion. Each of the first portion, the second portion, and the bridge area has an initial hardness, and the electrical steel lamination has an initial magnetic permeability. After isolating, the method includes hardening only the bridge area so that the bridge area has a treated hardness that is greater than the initial hardness. Concurrent to hardening, the method includes decreasing the initial magnetic permeability at only the bridge area.

The friction stir welding apparatus includes a pin (20) on which a soft nitrided layer (50) is formed. The soft nitrided layer (50) is formed of an iron lithium oxide layer (51) and a nitrided diffusion layer (52). The atom of the iron lithium oxide layer (51) penetrates into a space between atoms at the surface of the pin (20) to form the nitrided diffusion layer (52).

An object of the disclosure is to provide a heat generation element having high durability and a method of manufacturing the same. A heat generation element 1 according to the disclosure includes a first layer 2 having a metallic tantalum phase, and a second layer 3 which covers a periphery of the first layer 2 and has a tantalum carbide phase, wherein a concentration of silicon in an interface portion 4 between the first layer 2 and the second layer 3 is higher than a concentration of silicon in a portion other than the interface portion 4.