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:
Nov. 16, 1993
Filed:
Apr. 24, 1992
Huels Aktiengesellschaft, Marl, DE;
Abstract
The invention relates to polycrystalline, sintered abrasive granules based on .alpha.-Al.sub.2 O.sub.3 with a density of >98% of the theoretical density of corundum, a Vickers hardness of 21 GPa and greater and a crystallite size of 0.05 to 1.3 micron, as well as abrasives made from these abrasive granules and the use of these abrasive granules for the production of ceramic, refractory products. The polycrystalline, sintered abrasive granules based on .alpha.-Al.sub.2 O.sub.3 are produced by .alpha.-Al.sub.2 O.sub.3 crystal nuclei being added to a boehmite dispersion, the mixture of the boehmite dispersion and the crystal nuclei being acidified and gelled and the gel being dried, crushed, and sintered. In doing so, 0.5 to 35% by weight of .alpha.-Al.sub.2 O.sub.3 crystal nuclei, relative to the sintered abrasive granules, is added and the mixture of the boehmite dispersion and of the crystal nuclei is refluxed, while the pH of the mixture is kept in a range of 2.5 to 3.5 by adding acid.