Chemistry of inorganic compounds – Oxygen or compound thereof – Metal containing
Patent
1988-02-01
1989-05-23
Stoll, Robert L.
Chemistry of inorganic compounds
Oxygen or compound thereof
Metal containing
423 71, 423 84, 423265, 423266, 423274, 423275, 423608, 423609, 423610, 501134, 501136, 501137, 501138, 501139, 502525, C01G 2304
Patent
active
048329398
ABSTRACT:
The present invention involves a method for producing a variety of barium titanate based powder products consisting of submicron, dispersible primary particles having narrow size distributions. The method, in its broadest aspects, involves heating an aqueous slurry of PbO, or Pb(OH).sub.2, and Ca(OH).sub.2 with a stoichiometric excess of the hydrous oxides of Ti(IV), Sn(IV), Zr(IV) and Hf(IV) to a temperature not exceeding 200.degree. C. Thereafter, the resulting slurry temperature is adjusted to between 50.degree. and 200.degree. C. and a solution of Ba(OH).sub.2 and Sr(OH).sub.2, having a temperature of 70.degree. to 100.degree. C. is added within a period of five minutes or less to the slurry. About 10 minutes after the addition of the Ba(OH).sub.2 and Sr(OH).sub.2 solution is completed, the slurry is heated to a temperature not exceeding 225.degree. C. to ensure formation of a stoichiometric perovskite product. Thereafter, the slurry is cooled and the solid product is recovered.
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Gallagher et al., "Preparation of Semi-Conducting Titanates by Chemical Methods", J. Amer. Ceramics Soc., 46, No. 8, 1963, pp. 359-365.
Menashi Jameel
Reid Robert C.
Wagner Laurence P.
Cabot Corporation
Chaletsky Lawrence A.
Harvey Paige C.
Stoll Robert L.
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