Compositions: ceramic – Ceramic compositions – Synthetic precious stones
Patent
1994-08-10
1996-01-16
Bonner, C. Melissa
Compositions: ceramic
Ceramic compositions
Synthetic precious stones
501152, 501153, 501127, 501132, 252582, 2523014F, 2523014R, C04B 3550, C04B 35115, C04B 3544
Patent
active
054847508
ABSTRACT:
Transparent, polycrystalline garnet bodies having desirable properties for use as laser material, luminescent x-ray scintillator materials and other uses are produced by mixing a chloride source solution of the desired cations with a basic ammonium solution to produce a precipitate having a substantially uniform composition which can be further processed to provide the desired transparent body. This precipitate is separated from the solution, dried, thermally decomposed at a temperature in the range from 700.degree. to 1,000.degree. C., pressed to form a compact, isostatically pressed at up to 60,000 psi to provide a green, unsintered compact having a density in the vicinity of 55% of theoretic density. That green compact is then sintered in oxygen at a temperature between 1,400.degree. and 1,700.degree. C. to produce the desired transparent body. Alternatively, the compact may be sintered in oxygen at temperatures in the range from about 1,400.degree. to about 1,600.degree. C. to a closed pore stage and then hot isostatically pressed at high pressure to provide the desired transparent body.
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Greskovich Charles D.
Gurmen Erdogan O.
Minnear William P.
O'Clair Chester R.
Riedner Robert J.
Bonner C. Melissa
General Electric Company
Snyder Marvin
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