SURFACE-HARDENED TITANIUM MATERIAL, SURFACE HARDENING METHOD OF TITANIUM MATERIAL, WATCHCASE DECORATION ARTICLE, AND DECORATION ARTICLE

摘要

The invention provides a method of surface hardening a titanium material wherein titanium-aluminum alloy powders or aluminum oxide powders are brought into contact with the surface of the titanium material, and a heat treatment is applied thereto, causing aluminum contained in the powders to be diffused in the surface of the titanium material so that intermetallic compounds such as Ti3Al, TiAl, and the like are formed immediately underneath the surface of the titanium material, thereby enhancing surface hardness without causing surface exfoliation. The invention also provides a surface-hardened titanium-base material, and decorative articles and watchcases, composed of the surface-hardened titanium-base material, which are substantially impervious to scratches, and not prone to cause metallic allergy.