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:
May. 25, 1999
Filed:
Mar. 15, 1994
Tadahiro Ohmi, Aoba-ku, Sendai-shi, Miyagi-ken 980, JP;
Other;
Abstract
A reduced pressure device the reduced pressure chamber of which is constructed of stainless steel, and includes a passivation film formed on the exposed interior surface thereof. The film has a thickness of more than 50 .ANG. and is composed of two or more layers. One layer contains mainly chrome oxide formed in the vicinity of the interface of the stainless steel and the passivation film. The other layer contains mainly iron oxide formed in the vicinity of the surface of the passivation film. A passivation film may also be used with a thickness of more than 50 .ANG. and containing mainly a mixture of chrome oxide and iron oxide. Lastly a passivation film may also be used with thickness of more than 50 .ANG. and containing mainly chrome oxide.