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. 02, 1990
Filed:
Oct. 25, 1988
Saburo Hori, Tokyo, JP;
Ryuichi Kurita, Iwaki, JP;
Kureha Chemical Industry Co., Ltd., Tokyo, JP;
Abstract
A mullite-alumina composite sintered body composed of from 75 wt % to 85 wt % Al.sub.2 O.sub.3 balance SiO.sub.2, consisting of two crystalline phases, mullite and .alpha.-phase alumina, and being free from glass phase, wherein both of the average diameters of mullite grains and .alpha.-phase alumina grains are not more than 1.0 .mu.m, the content of grains having the longitudinal-length of not less than 2.5 .mu.m is 1% or less in the observation of a cross section of said sintered body, and the porosity of said sintered body is 1% or less. The sintered body of the present invention is produced by a process comprising the steps of preparing a starting powdery material composed of from 75 wt % to 85 wt % Al.sub.2 O.sub.3 balance SiO.sub.2 and containing amorphous phase from 65 wt % to 90 wt %, wherein each particle of said starting powdery material contains both Al.sub.2 O.sub.3 and SiO.sub.2, and sintering said starting powdery material at a temperature in the range from 1500.degree. C. to 1650.degree. C. The sintered body of the present invention has a high bending strength exceeding 500 MPa at room temperature.