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. 13, 2001
Filed:
Feb. 28, 1997
Masanori Okabe, Saitama, JP;
Kagehisa Hamazaki, Saitama, JP;
Honda Giken Kogyo Kabushiki Kaisha, Tokyo, JP;
Abstract
There is disclosed a silicon nitride sintered body produced by sintering a molded article which comprises a mixture of a silicon nitride powder as the main component and plural kinds of sintering additives, wherein said silicon nitride powder is set to be 0.1 to 1.0 &mgr;m in average grain size, and said plural kinds of sintering additives includes first and second sintering additives, said first sintering additive comprising oxide powders of at least one element of Group 3a element, said second sintering additive comprising oxide powders of at least one element selected from Zr (zirconium), Hf (hafnium), Nb (niobium), Ta (tantalum) and W (tungsten), said first sintering additive having the average grain size set to be 0.1 to 10 times as large as the average grain size of said silicon nitride powder and being incorporated in an amount ranging from 0.1 to 10% by weight to the mixture, said second sintering additive being such particles as that part of the particles are of grain size in the range from 10 to 100 times as large as the average grain size of said silicon nitride powder but the number of such part of the particles is in the 5 to 50% range of the total particle number and being incorporated in an amount ranging from 0 to 10% by weight to the mixture (provided that 0% by weight is not included). The sintering process of the molded article comprises a primary sintering in an atmosphere containing a nitrogen gas under the atmospheric pressure from 1 to 20 kgf/cm,at 1600-1800° C., and subsequently secondary sintering in an atmosphere containing a nitrogen gas under the atmospheric pressure ranging from 100 to 2000 kgf/cm,at a temperature lower than that of primary sintering.