| 摘要 |
Titanates of barium, strontium, or mixed barium and strontium consisting essentially of solid, non-aggregated particles having diameters ranging from 0.05 to 1 micron and a narrow particle size distribution expressed by the polydispersity index, dw/dn, not greater than 1.20, where dw is the weight average diameter and dn is the number average diameter, said particles being essentially perfectly spherical with a total mean axial ratio of at least 0.93. These titanates are prepared by a process which comprises precipitating of a peroxidic precursor having the same morphological characteristics of the titanates. The peroxidic precursor is obtained by heating an alkaline solution comprising a complex of a titanium compound with a peroxidic compound, an M2+ compound, wherein M is Ba, Sr or mixtures thereof, and a compound Z capable of complexing with the M2+ ion oxidizable by the peroxidic compound under the conditions of reaction to produce soluble decomposition products and provide a homogeneous precipitation of the peroxidic precursor comprising titanium and M2+. Subsequently the precursor is heated to a temperature of at least 100 DEG C. to obtain the corresponding titanate having the above-indicated morphological characteristics.
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