Factors of Impacting the Coprecipitation Process for Synthesizing CoTi-substitued Barium M-type Ferrite Ultrafine Powder

摘要

The effect of pH values on synthesizing single-phase CoTi-substituted barium. M-type fertile ul-trafine powders, and BaCoTiFe_(10)O(19). was investigated employing corrosion versus pH plot (E-pH plot) for metalelement, thermodynamic calculation, and co-dump coprecipitation. The pH values of complete coprecipitation of all Fe~(3+), Ti~(4+) Co~(2+) and Ba~(2+) cations are 9-12 and higher than 7.9 on the basis of E-pH plot analysis andthennodynamic calculation, respectively. The minimum pH value necessary to the formation of single-phase. Ba-CoTiFe_(10)O_(19) is 8.5 in the light of the co-dump coprecipitation. These results indicate that the coprecipitation process for synthesizing CoTi-substituted barium M-type ferrite ultrafine powders is simultaneously influenced by syner-getic coprecipation effect of cations and coordination effect of Cl anions. The test time of the minimum pH value corresponding to forming a series of single-phase CoTi-substituted barium M-type ferrite ultrafine powders, and Ba-Co_xTi_xFe_(12-2x)O_(19), may be significantly reduced by using the effects of two new factors on the coprecipitation process.