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:
Sep. 21, 1993
Filed:
Oct. 02, 1992
Luc Parent, Chicoutimi, CA;
Mukesh Jain, Jonquiere, CA;
Alcan Internatonal Limited, Montreal, CA;
Abstract
A process for producing small particles of aluminum nitride suitable for sintering and the particles thus-produced. The process comprises reacting particles of gamma alumina, or a precursor thereof, of less than 1 micron in size with a stoichiometrical excess of finely divided carbon in the presence of nitrogen, or a precursor which provides nitrogen in the reaction conditions, first at a temperature in the range of 1550.degree. to 1700.degree. C. for a period of between 1 and 6 (preferably 1 to 4) hours and then at a temperature in the range of 1750.degree. to 1850.degree. C. for a period of 1 to 4 (preferably 1 to 2) hours, followed by cooling said reaction mixture and reheating to a temperature in the range of 500.degree. to 700.degree. C. in an oxygen-containing atmosphere, and maintaining the temperature until excess unreacted carbon is removed. The alumina or precursor preferably has a particle size of less than 400 nm and the carbon source preferably contains iron as an impurity, and is preferably petroleum coke. The AlN product is particularly suited for use in forming a substrate for electronic components by a process involving sintering of the AlN particles because of the small size (less than 2 microns) and narrow size distribution of the particles.