The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Apr. 24, 2001
Filed:
Sep. 24, 1998
Yoshitsugu Shibuya, Omiya, JP;
Masahiro Sato, Iruma, JP;
Junji Sato, Kawagoe, JP;
Takanori Nanya, Sayama, JP;
Kenji Hanai, Musashimurayama, JP;
Citizen Watch Co., Ltd., Tokyo, JP;
Abstract
Disposing the titanium or titanium alloy in a vacuum vessel, and applying annealing treatment thereto by heating (a heating process); feeding a mixed gas consisting primarily of nitrogen with a trace of oxygen component into the vessel, and heating inside the vacuum vessel at temperatures in the range of 700 to 800° C. in a predetermined reduced pressure condition for a predetermined length of time such that nitrogen and oxygen are diffused into the interior of the titanium or titanium alloy from the surface thereof so as to pass into solid solution therein (a hardening treatment process); and cooling the titanium or titanium alloy to room temperature after the hardening treatment process (a cooling process), are carried out. After completion of the processes described above, a hard surface layer,is formed in the surface region of the titanium or titanium alloy,The hard surface layer,comprises a first hard layer,where nitrogen atoms,and oxygen atoms,reside in solid solution, and a second hard layer,where oxygen atoms,reside in solid solution.