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:
Oct. 17, 1995
Filed:
Feb. 01, 1994
Toshio Nozaki, Nagoya, JP;
Seigo Ohiwa, Nagoya, JP;
Hiroshi Iwase, Fuji, JP;
Masanori Oguni, Shimizu, JP;
Sumitomo Metal Ceramics Inc., Mine, JP;
Abstract
A sinterable aluminum nitride powder composition is prepared by adding about 0.05-10.0 parts by weight of at least one compound selected from the group consisting of calcium tungstate and calcium molybdate and optionally about 1.0-7.0 parts by weight of at least one compound selected from the group consisting of yttria, calcium oxide, and calcium carbonate to 100 parts by weight of an aluminum nitride powder prepared by the alumina reduction method without decarbonization and having a residual carbon content of about 2%-10% by weight. The resulting powdery composition is subjected to mixing and deagglomeration in a dry process so as to form a powder mixture having a bulk density of about 0.3-0.5 g/cm.sup.3, and then to decarbonization by heating in an oxidizing atmosphere. The aluminum nitride powder composition has a pressurized bulk density of about 1.50-1.75 g/cm.sup.3 as measured at a pressure of 500 kg/cm.sup.2 and an average particle diameter of about 1.0-3.0 .mu.m in which particles having a diameter of 5 .mu.m or larger comprise not greater than about 10% by weight of the powder composition. It is capable of forming a colored sintered body with little or no unevenness of color and sintering, and is also capable of forming green sheets which can be used in the manufacture of a multilayered substrate by the green sheet laminating technology with a minimized tendency toward delamination during sintering.