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:
May. 08, 1990
Filed:
Jun. 09, 1989
Hoechst Aktiengesellschaft, Frankfurt am Main, DE;
Abstract
An aluminum nitride powder has a crystallite size of 40 to 150 nm, measured by powder diffractometry and evaluated by the method of Scherrer, a primary particle size of 0.1 to 0.5 .mu.m, a specific surface according to BET of 5 to 50 m.sup.2 /g and a degree of whiteness of more than 91%, measured using light of a 400 to 700 nm wavelength against barium sulfate analytical reagent as standard of whitness. To prepare this aluminum nitride powder, metallic aluminum and monoamminealuminum chloride [AlCl.sub.3 (NH.sub.3)] are first molten together in an inert gas atmosphere at temperatures above 125.degree. C. and allowed to react with one another with evolution of hydrogen. 8 to 20 g of ammonia are then introduced per hour per mol of monoamminealuminum chloride into the aluminum-containing monoamminealuminum chloride melt at temperatures between 250.degree. and 400.degree. C., aluminum nitride being precipitated as a solid until the conversion of the aluminum is complete. The temperature of the melt is finally raised to more than 400.degree. C.