Chemistry of inorganic compounds – Rare earth compound
Reexamination Certificate
2011-05-03
2011-05-03
Mayes, Melvin C (Department: 1732)
Chemistry of inorganic compounds
Rare earth compound
C423S412000, C148S030000, C148S317000, C117S011000, C117S073000, C117S054000, C252S518100
Reexamination Certificate
active
07935325
ABSTRACT:
Rare earth-activated aluminum nitride powders are made using a solution-based approach to form a mixed hydroxide of aluminum and a rare earth metal, the mixed hydroxide is then converted into an ammonium metal fluoride, preferably a rare earth-substituted ammonium aluminum hexafluoride ((NH4)3Al1-xRExF6), and finally the rare earth-activated aluminum nitride is formed by ammonolysis of the ammonium metal fluoride at a high temperature. The use of a fluoride precursor in this process avoids sources of oxygen during the final ammonolysis step which is a major source of defects in the powder synthesis of nitrides. Also, because the aluminum nitride is formed from a mixed hydroxide co-precipitate, the distribution of the dopants in the powder is substantially homogeneous in each particle.
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Han Bing
Klinedinst Keith A.
Mishra Kailash A.
Raukas Madis
Talbot Jan B.
Clark Robert F.
Gregorio Guinever S
Mayes Melvin C
Osram Sylvania Inc.
The Regents of the University of California
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