Citizen Watch Company, Ltd.

Kabushiki Kaisha Kobe Seiko Sho

Hachiro Kushida

Kenji Irie

Tsuneji Takasugi

Toshio Murata

Tadao Enomoto

Norio Hashimoto

Shinji Ikeda

Hideo Taguchi

Kazumi Hamano

Atsushi Takemura

Takashi Shiono

Yoshitsugu Imazawa

High strength titanium alloy, product made of the titanium alloy and

A metal-made ornamental article, such as watch cases and the like, is provided with a bilayered coating layer composed of an undercoating layer of a specified thickness formed from an aqueous colloidal solution of sodium silicate and silica sol in a specified proportion and a top-coating layer of a specified thickness formed by coating with a solution of a partial hydrolysis-condensation product of an organic silicate ester compound, such as ethyl silicate, followed by baking to effect curing of the coating layer.

Method of preparation of a surface-coated metal-made ornamental article

A body of an external member is made of an aluminum alloy containing 0.5-2.5% of magnesium by weight, less than 0.01% of silicon by weight, and less than 0.01% of iron by weight. An anodic oxide film is formed on the body.

External member for a watch

The invention provides a means for solving the difficult problem of the deposition of stain in the recesses to cause loss of beautiful appearance on the matted surface of an article for personal ornament made of titanium, zirconium or an alloy thereof formed by honing or barrel finishing. The method comprises the steps of (a) forming a first matted surface with microscopically fine protrusions and recesses on the article by honing or barrel finishing, (b) forming a hardened layer on the matted surface by nitriding, carbonizing, boriding or oxidizing, (c) partially removing the hardened layer covering the protrusions on the matted surface by a first electrolytic or chemical polishing, (d) forming a second matted surface on the article by honing or barrel finishing, and (e) partially removing the surface layer at the protrusions by a second electrolytic or chemical polishing to smoothen the surface leaving a sandy appearance.

Method for finishing matted surface on a metal-made article for personal

The polyhedral body of aluminum such as a watch case obtained by the inventive method is colored in two different colors on different polyhedral faces demarcated by the ridgeline therebetween with remarkable decisiveness not obtained in the prior art methods. The inventive method utilizes anodization and coloring by dyeing in two steps. A part of the polyhedral faces anodized and colored in a dark color in the first step is ground to expose the bare surface of aluminum, which is then activated by dipping in an aqueous acid solution and again anodized by applying an unconventionally high voltage in an electrolyte bath of a specific composition followed by coloring in a light color decoratively distinguishable from the dark color imparted in the first step coloring. By virtue of the activation treatment of the bare aluminum surface and the unusual conditions in the second anodization, the demarcation between the differently colored polyhedral faces is very decisive and beautiful and the oxide films on both sides of the ridgeline have excellent adhesion and high anti-corrosion resistance.

Method for manufacturing bicolored polyhedral body of aluminum

The invention concerns a process for the manufacture of a decorative aluminum alloy product such as a watch case. In the first step, several aluminum sheets are united tightly into a stock by their overlapping and pressure-welding. The compacted stock is subjected to a forging step for agitating substantial part of the composite stock in its regularly laminated structure. Then, a watch case material is punched out from the composite stock which is further subjected to an anodically oxidizing step and a mirror finish step to provide the final product. The invention relates also the thus finished final product, having an attractive and contrasted flow design pattern on its exposed surface and in any section thereof.

Process for the manufacture of a decorative aluminum product

Growing community of inventors

Tanashi, Japan

Hachiro Kushida