C - Chemistry – Metallurgy – 30 – B
Patent
C - Chemistry, Metallurgy
30
B
C30B 29/38 (2006.01) C22C 32/00 (2006.01) C30B 25/00 (2006.01)
Patent
CA 2083708
2083708 9119027 PCTABS00008 A process for producing unagglomerated single crystals of aluminum nitride having a size of at least 10 microns suitable for the reinforcement of metal, ceramic and polymeric matrix composite materials. The process involves reacting alumina (or a precursor) with carbon (or a precursor) under an atmosphere of nitrogen (or a precursor such as ammonia or an amine) at a temperature in the range of 1700 - 1950 ·C in the presence of an alkali metal oxide (or precursor such as a carbonate) as a crystal growth promoter or catalyst. The alkali metal oxide is present in an amount required for the formation of crystals of the required size, preferably in the range of 10 - 60 microns. Particularly desirable crystals are produced if electrostatic precipitator dust is used as a source of the alumina, if petroleum coke or calcined anthracite coal is used as a source of the carbon and if the reaction is carried out in the presence of a porosity enhancer for the reaction mass, especially short cellulose fibres. The particles produced by the invention are in the form of large single crystals for good matrix reinforcement and may have low oxygen and carbon contents. Moreover, to reduce the oxygen content even further, the reaction mixture may be subjected to a preheating step under nitrogen at a temperature in the range of 1600 - 1700 ·C prior to further reaction under nitrogen at 1800 - 1950 ·C. The invention extends to the particles produced by the process and to matrix composites reinforced with the particles.
Nadkarni Sadashiv K.
Parent Luc
Alcan International Limited
Kirby Eades Gale Baker
LandOfFree
Process for producing unagglomerated single crystals of... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Process for producing unagglomerated single crystals of..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Process for producing unagglomerated single crystals of... will most certainly appreciate the feedback.
Profile ID: LFCA-PAI-O-1457539