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:
Feb. 26, 1991
Filed:
Jul. 10, 1990
Norikazu Shindo, Chofu, JP;
Tomoyuki Sekine, Chofu, JP;
Yoshikatsu Nakamura, Omiya, JP;
Takashi Kawamoto, Urawa, JP;
Juki Corporation, Tokyo, JP;
Nippon Piston Ring Co., Ltd., Tokyo, JP;
Abstract
A sintered body is produced by a process comprising the steps of mixing one or more metal powder particles with an organic binder, injection-molding the mixture to form a green body of a predetermined shape, removing the binder from the green body to form a porous body substantially made of the metal powder, and heating the porous body to a sintering temperature and holding it at that temperature to produce a sintered body, in which process the binder is removed through the sequence of the following steps: preheating the green body in an inert gas atmosphere in a temperature range that creates open pores in it; placing the green body, in which open pores have started to form, in a hydrogen gas atmosphere optionally mixed with an inert gas; holding the green body in a temperature range where the metal powder is not carburized and where the open pores will be maintained, so that the greater part of the binder is removed to form a porous body that is substantially made of the metal powder alone; and further holding said porous body at said heating temperature for a sufficient period of time to vaporize the carbon in the small amount of residual binder in the porous body through reaction with hydrogen.