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:
Jun. 06, 1989
Filed:
Jan. 07, 1987
Terrance L Bescup, Woodbury, MN (US);
Benjamin T Fellows, Oakdale, MN (US);
Charles J Leedecke, Northford, CT (US);
Minnesota Mining and Manufacturing Company, St. Paul, MN (US);
Abstract
Procedure for making Al.sub.2 O.sub.3 spheroids, 600 micrometers in diameter or less, utilizes an AlOOH sol containing 0.25% weight percent MgO (in the form of Mg(NO.sub.3).sub.2 .multidot.6H.sub.2 O) and HNO.sub.3. The sol is dispersed into droplets in a particle forming fluid (e.g., 2-ethylhexanol) where gelling occurs. The gelled spheroids are collected, dried and pre-fired in air at temperatures less than 1,200.degree. C. for up to about 12 hours. The dried and prefired beads are fired in a 2-step process at temperatures of about 1,850-1,950.degree. C. in the following sequence: