A platinum alloy consisting, by weight, of the following elements: 95.00 to 96.00% of Pt, 1.00 to 4.95% of Ru, 0.05 to 2.00% of Ge, 0 to 2.00% of Au, any impurities with a total content≤0.50%.

An exterior member that is favorably manufactured, a case having the exterior member and a timepiece having the case are provided. The exterior member includes an exterior main body section in which a first resin layer is provided on one side of a sheet member formed of carbon fiber and a cutout recess section from which a portion of the sheet member is exposed is provided in the first resin layer on the one side of the sheet member, and a protection member which covers the cutout recess section of the first resin layer. Accordingly, the exterior member is favorably manufactured with its strength being increased.

A method for fabrication of a micromechanical part made of a one-piece synthetic carbon allotrope based material, the method including: forming a substrate with a negative cavity of the micromechanical part to be fabricated; coating the negative cavity of the substrate with a layer of the synthetic carbon allotrope based material in a smaller thickness than the depth of the negative cavity; and removing the substrate to release the one-piece micromechanical part formed in the negative cavity.

A method for fabrication of a micromechanical part made of a one-piece synthetic carbon allotrope based material, the method including: forming a substrate with a negative cavity of the micromechanical part to be fabricated; coating the negative cavity of the substrate with a layer of the synthetic carbon allotrope based material in a smaller thickness than the depth of the negative cavity; and removing the substrate to release the one-piece micromechanical part formed in the negative cavity.

A watch component includes a metal material obtained by performing a nitrogen absorption treatment on a base material, the base material being a ferritic stainless steel that contains, by mass %, 18 to 22% of Cr, 1.3 to 2.8% of Mo, 0.05 to 0.50% of Nb, less than 0.5% of Ni, less than 0.8% of Mn, less than 0.5% of Si, less than 0.10% of P, less than 0.05% of S, less than 0.05% of N, and less than 0.05% of C, with a remainder thereof being composed of Fe and an unavoidable impurity.

A watch component includes a metal material obtained by performing a nitrogen absorption treatment on a base material, the base material being a ferritic stainless steel that contains, by mass %, 18 to 22% of Cr, 1.3 to 2.8% of Mo, 0.05 to 0.50% of Nb, less than 0.5% of Ni, less than 0.8% of Mn, less than 0.5% of Si, less than 0.10% of P, less than 0.05% of S, less than 0.05% of N, and less than 0.05% of C, with a remainder thereof being composed of Fe and an unavoidable impurity.

An electronic timepiece includes an outer case, a back cover, and an antenna for receiving radio waves disposed in the outer case, wherein at least one of the outer case and the back cover is formed from a titanium alloy composed of aluminum in an amount of 3.50 mass % or more and 4.50 mass % or less and vanadium in an amount of 20.00 mass % or more and 23.00 mass % or less, with the remainder including titanium and impurities.

An electronic timepiece includes an outer case, a back cover, and an antenna for receiving radio waves disposed in the outer case, wherein at least one of the outer case and the back cover is formed from a titanium alloy composed of aluminum in an amount of 3.50 mass % or more and 4.50 mass % or less and vanadium in an amount of 20.00 mass % or more and 23.00 mass % or less, with the remainder including titanium and impurities.

A watch component comprising an austenitic ferritic stainless steel. The austenitic ferritic stainless steel includes a base portion composed of a ferrite phase, a surface layer composed of an austenitic phase, and a mixed layer formed between the base portion and the surface layer, wherein the mixed layer is composed of the ferrite phase and the austenitic phase. The surface layer contains 1.0 to 1.6 mass % of nitrogen, in which the surface layer has, at a surface of the surface layer, an oxide film having a thickness of 2.5 nm or greater, as calculated in terms of oxygen profiles in AES analysis.

A watch component comprising an austenitic ferritic stainless steel. The austenitic ferritic stainless steel includes a base portion composed of a ferrite phase, a surface layer composed of an austenitic phase, and a mixed layer formed between the base portion and the surface layer, wherein the mixed layer is composed of the ferrite phase and the austenitic phase. The surface layer contains 1.0 to 1.6 mass % of nitrogen, in which the surface layer has, at a surface of the surface layer, an oxide film having a thickness of 2.5 nm or greater, as calculated in terms of oxygen profiles in AES analysis.