| 摘要 |
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)2, and Ca(OH)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 DEG C. Thereafter, the resulting slurry temperature is adjusted to between 50 DEG and 200 DEG C. and a solution of Ba(OH)2 and Sr(OH)2, having a temperature of 70 DEG to 100 DEG C. is added within a period of five minutes or less to the slurry. About 10 minutes after the addition of the Ba(OH)2 and Sr(OH)2 solution is completed, the slurry is heated to a temperature not exceeding 225 DEG C. to ensure formation of a stoichiometric perovskite product. Thereafter, the slurry is cooled and the solid product is recovered.
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