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:
Aug. 12, 1980
Filed:
Oct. 30, 1978
Applicant:
Inventors:
Assignee:
Fujitsu Limited, , JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
C01F / ; C04B / ;
U.S. Cl.
CPC ...
423626 ; 106 734 ;
Abstract
Disclosed is an alumina substrate having a high density, a high degree of surface smoothness and excellent dielectric properties and a process for its manufacture. The process comprises prefiring a green sheet prepared from alumina powder at an elevated temperature, for example between 1200.degree. and 1350.degree. C., to remove combustible substances from the sheet, treating the resultant prefired substrate with an acid aqueous solution to eliminate acid-soluble and decomposable substances from the substrate, and firing the acid-treated substrate at an elevated temperature, for example between 1500.degree. and 1650.degree. C.