Abstract: In forming alumina films on substrates by sputtering of an aluminum metal target in an oxidizing gas-containing atmosphere, film formation is carried out intermittently in a plurality of substeps while restricting a thickness of the film formed in each substep to at most 5 nm. A turntable is disposed to face a direction of sputtering of the aluminum metal target and the substrates are fixed to the turntable.

Abstract: The present invention provides a process for producing an alumina coating comprised mainly of ? crystal structure on a base material.

Abstract: Provided is a protective alumina film mainly containing alumina in the ?-crystal structure and fine crystal grains in which one or more regions containing additionally an element other than aluminum formed along the planes in the direction almost perpendicular to the thickness direction of the protective film are present intermittently in the thickness direction inside the protective film.

Abstract: The present invention provides a method for reactive sputtering in which a reactive sputtering apparatus including a sputtering vaporization source 2 provided with a metal target disposed in a vacuum chamber 1, a sputtering power source 4 to drive the sputtering vaporization source 2, and an introduction mechanism 5 to introduce an inert gas for sputtering and a reaction gas for forming a compound with sputtered metal into the vacuum chamber 1 is used, and reactive sputtering film formation is performed on a substrate 3 disposed in the above-described vacuum chamber, wherein the method includes the steps of performing constant-voltage control to control the voltage of the above-described sputtering power source 4 at a target voltage Vs and, in addition, performing target voltage control at a control speed lower than the speed of the above-described constant-voltage control, the target voltage control operating the above-described target voltage Vs in order that the spectrum of plasma emission generated forwar

Abstract: In forming alumina films on substrates by sputtering of an aluminum metal target in an oxidizing gas-containing atmosphere, film formation is carried out intermittently in a plurality of substeps while restricting a thickness of the film formed in each substep to at most 5 nm. A turntable is disposed to face a direction of sputtering of the aluminum metal target and the substrates are fixed to the turntable.

Abstract: Provided is a protective alumina film mainly containing alumina in the ?-crystal structure and fine crystal grains in which one or more regions containing additionally an element other than aluminum formed along the planes in the direction almost perpendicular to the thickness direction of the protective film are present intermittently in the thickness direction inside the protective film.

Abstract: For forming alumina films on substrates by sputtering of an aluminum metal target in an oxidizing gas-containing atmosphere, a method of producing ? crystal structure-based alumina films efficiently includes as an early film formation, forming films under conditions suited for formation of ? crystal structure alumina. For example the forming forms films of ?crystal structure alumina in a poisoning mode discharge condition only in an early stage of film formation.

Abstract: Provided is a protective alumina film mainly containing alumina in the ?-crystal structure and fine crystal grains in which one or more regions containing additionally an element other than aluminum formed along the planes in the direction almost perpendicular to the thickness direction of the protective film are present intermittently in the thickness direction inside the protective film.

Abstract: Provided is a method of producing an alumina film mainly in alpha crystal structure superior in heat resistance, wherein the alumina film mainly in alpha crystal structure is formed on a substrate, independently of the kind of the substrate at relatively low temperature, by treating the substrate surface with a ceramic powder mainly having the crystal structure same as that of alumina in the alpha crystal structure, in forming the alumina film mainly in alpha crystal structure on the substrate (including the substrate having a film previously formed thereon).

Abstract: The present invention provides a process for producing an alumina coating comprised mainly of ? crystal structure on a base material.

Abstract: The present invention provides a process for producing an alumina coating comprised mainly of ? crystal structure on a base material.

Abstract: The present invention provides a process for producing an alumina coating comprised mainly of ? crystal structure on a base material.

Abstract: A multilayered film of the present invention includes a hard film provided on a substrate and including a compound of essential metal components, Al and Ti, with C, N, B, or O, and an intermediate layer formed between the substrate and the hard film, the intermediate layer including at least one selected from the group consisting of a metal, an alloy, and a compound of the metal or the alloy, and having an oxidation temperature lower than that of the hard film. The multilayered film further includes an oxide-containing layer formed by oxidizing the hard film, and an alumina film formed on the surface of the oxide-containing layer. The multilayered film of the present invention has excellent adhesion to the substrate, excellent heat resistance, and excellent oxidation resistance when being exposed to a substrate temperature of 700° C. or more and an oxidizing atmosphere.

Abstract: A multilayer coating according to the present invention comprises an alumina coating formed, directly or through an intermediate layer, on a hard coating composed of a metallic compound formed on the base material, and the Vickers hardness of the hard coating after alumina coating formation being 22 GPa or more. The multilayer coating is excellent in adhesion between a hard coating and an alumina coating and capable of exhibiting excellent wear resistance and heat resistance over a long period.

Abstract: Provided is a protective alumina film mainly containing alumina in the ?-crystal structure and fine crystal grains in which one or more regions containing additionally an element other than aluminum formed along the planes in the direction almost perpendicular to the thickness direction of the protective film are present intermittently in the thickness direction inside the protective film.

Abstract: Provided is a method of producing an alumina film mainly in ? crystal structure superior in heat resistance, wherein the alumina film mainly in ? crystal structure is formed on a substrate, independently of the kind of the substrate at relatively low temperature, by treating the substrate surface with a ceramic powder mainly having the crystal structure same as that of alumina in the ? crystal structure, in forming the alumina film mainly in ? crystal structure on the substrate (including the substrate having a film previously formed thereon).

Abstract: The present invention provides a method for producing an ?-alumina-formed member, comprising (1) a process for forming an alumina layer of ?-type crystal structure on at least a partial surface of a base material; and (2) a process for performing an ion bombardment treatment to the surface of the resulting alumina layer. With an ?-alumina film formed thereon according to this method, the tool life can be extended in case of a tool, and the frictional resistance can be reduced in case of a sliding member, a metal mold and the like.

Abstract: A multilayer coating according to the present invention comprises an alumina coating formed, directly or through an intermediate layer, on a hard coating composed of a metallic compound formed on the base material, and the Vickers hardness of the hard coating after alumina coating formation being 22 GPa or more. The multilayer coating is excellent in adhesion between a hard coating and an alumina coating and capable of exhibiting excellent wear resistance and heat resistance over a long period.

Abstract: For forming alumina films on substrates by sputtering of an aluminum metal target in an oxidizing gas-containing atmosphere, a method of producing ? crystal structure-based alumina films efficiently includes as an early film formation, forming films under conditions suited for formation of ? crystal structure alumina. For example the forming forms films of ? crystal structure alumina in a poisoning mode discharge condition only in an early stage of film formation.

Abstract: A process for producing an alumina coating composed mainly of a-type crystal structure especially excelling in heat resistance, comprising (1) providing a laminate coating including a hard coating composed of a metal component containing Al and Ti as unavoidable elements and a compound of B, C, N, O, etc., oxidizing the hard coating to thereby form an oxide-containing layer, and forming an alumina coating composed mainly of a-type crystal structure on the oxide-containing layer. Alternatively, the process comprises (2) forming a hard coating composed of a metal whose standard free energy for oxide formation is greater than that of aluminum and a compound of B, C, N, O, etc., oxidizing the surface of the hard coating to thereby form an oxide-containing layer, and forming an alumina coating while being accompanied by reduction of the oxide at the surface of the oxide-containing layer.