A material layer for a laminated core of an electric machine is made of iron-containing ferromagnetic material and includes an electrically insulating coating on at least one side of the material layer. The electrically insulating coating Includes an electrically Insulating material which Is produced through controlled oxidation of the ferromagnetic material of the material layer and contains iron monoxide and/or triiron tetraoxid. The material layer is produced from a green body, which Is sintered under a reducing atmosphere.

The present invention provides a method for manufacturing more beautiful black coated steel sheets by uniformly blackening the coating layer. Specifically, the present invention provides a method for manufacturing black coated steel sheets, which brings Zn—Al—Mg alloy coated steel sheets (1) into contact with steam in a closed container (10), wherein said closed container (10) can maintain a predefined internal pressure through variable control of the amount of steam flowing into said closed container (10) and/or the amount of steam flowing out of said closed container (10), and in said closed container (10) that can maintain said predefined pressure, said Zn—Al—Mg alloy coated steel sheets (1) have contact with the steam introduced into said closed container (10).

The present invention provides a method for manufacturing more beautiful black coated steel sheets by uniformly blackening the coating layer. Specifically, the present invention provides a method for manufacturing black coated steel sheets, which brings Zn—Al—Mg alloy coated steel sheets (1) into contact with steam in a closed container (10), wherein said closed container (10) can maintain a predefined internal pressure through variable control of the amount of steam flowing into said closed container (10) and/or the amount of steam flowing out of said closed container (10), and in said closed container (10) that can maintain said predefined pressure, said Zn—Al—Mg alloy coated steel sheets (1) have contact with the steam introduced into said closed container (10).

Provided is a fastening member having a base material including an aluminum alloy and an anticorrosive film with which the base material is coated. This anticorrosive film contains aluminum hydroxide oxide (AlO(OH)), and in a profile obtained from X-ray diffractometry with a Cu-Kα radiation on the fastening member, a peak intensity ratio R (I.sub.B(020)/I.sub.Al(200)) is 0.003 or more and 0.1 or less, wherein I.sub.B(020) is an intensity of a diffraction peak of a (020) plane of aluminum hydroxide oxide, and I.sub.Al(200) is an intensity of a diffraction peak of a (200) plane of aluminum as a main peak. The anticorrosive film formed by the present invention is uniformly formed on the fastening member and excellent in stability and adhesion.

Provided is a fastening member having a base material including an aluminum alloy and an anticorrosive film with which the base material is coated. This anticorrosive film contains aluminum hydroxide oxide (AlO(OH)), and in a profile obtained from X-ray diffractometry with a Cu-Kα radiation on the fastening member, a peak intensity ratio R (I.sub.B(020)/I.sub.Al(200)) is 0.003 or more and 0.1 or less, wherein I.sub.B(020) is an intensity of a diffraction peak of a (020) plane of aluminum hydroxide oxide, and I.sub.Al(200) is an intensity of a diffraction peak of a (200) plane of aluminum as a main peak. The anticorrosive film formed by the present invention is uniformly formed on the fastening member and excellent in stability and adhesion.

A hydrogen gas sensor with a substrate and a zinc oxide nanostructured thin film deposited on the substrate, wherein the zinc oxide nanostructured thin film has a lattice structure with a weight ratio of low binding energy O.sup.2− ions to medium binding energy oxygen vacancies in a range of 0.1 to 1.0, and a method of fabricating a gas sensor by thermally oxidizing a metal thin film under low oxygen partial pressure. Various combinations of embodiments of the hydrogen gas sensor and the method of fabricating the gas sensor are provided.

A hydrogen gas sensor with a substrate and a zinc oxide nanostructured thin film deposited on the substrate, wherein the zinc oxide nanostructured thin film has a lattice structure with a weight ratio of low binding energy O.sup.2− ions to medium binding energy oxygen vacancies in a range of 0.1 to 1.0, and a method of fabricating a gas sensor by thermally oxidizing a metal thin film under low oxygen partial pressure. Various combinations of embodiments of the hydrogen gas sensor and the method of fabricating the gas sensor are provided.

A hydrogen gas sensor with a substrate and a zinc oxide nanostructured thin film deposited on the substrate, wherein the zinc oxide nanostructured thin film has a lattice structure with a weight ratio of low binding energy O.sup.2− ions to medium binding energy oxygen vacancies in a range of 0.1 to 1.0, and a method of fabricating a gas sensor by thermally oxidizing a metal thin film under low oxygen partial pressure. Various combinations of embodiments of the hydrogen gas sensor and the method of fabricating the gas sensor are provided.

A hydrogen gas sensor with a substrate and a zinc oxide nanostructured thin film deposited on the substrate, wherein the zinc oxide nanostructured thin film has a lattice structure with a weight ratio of low binding energy O.sup.2− ions to medium binding energy oxygen vacancies in a range of 0.1 to 1.0, and a method of fabricating a gas sensor by thermally oxidizing a metal thin film under low oxygen partial pressure. Various combinations of embodiments of the hydrogen gas sensor and the method of fabricating the gas sensor are provided.

There is provided a titanium alloy member including a base metal portion, and an outer hardened layer formed on an outer layer of the base metal portion, the cross sectional hardness of the base metal portion is 330 HV or higher and lower than 400 HV, the cross sectional hardnesses at positions 5 μm and 15 μm from the surface of the outer hardened layer are 450 HV or higher and lower than 600 HV, the outer hardened layer includes an oxygen diffusion layer and a nitrogen diffusion layer, the oxygen diffusion layer is at a depth of 40 to 80 μm from the surface of the outer hardened layer, and the nitrogen diffusion layer is at a depth of 2 to 5 μm from surface of the outer hardened layer. This titanium alloy member includes an outer hardened layer, is high in cross sectional hardness of the base metal portion, and is excellent in fatigue strength and wear resistance.