Factors of impacting the coprecipitation process for synthesizing CoTi-substitued Barium M-type ferrite ultrafine powder

Abstract

The effect of pH values on synthesizing single-phase CoTi-substituted barium M-type ferrite ultrafine powders, and BaCoTiFe ₁₀O ₁₉, was investigated employing corrosion versus pH plot (E-pH plot) for metal element, thermodynamic calculation, and co-dump coprecipitation. The pH values of complete coprecipitation of all Fe ³⁺, Ti ⁴⁺, Co ²⁺ and Ba ²⁺ and Ba ²⁺ cations are9–12 and higher than7.9 on the basis of E-pH plot analysis and thermodynamic calculation, respectively. The miniumum pH value necessary to the formation of single-phase BaCoTiFe ₁₀O ₁₉ is8.5 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 synergetic 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 _12−2xO ₁₉. may be significantly reduced by using the effects of two new factors on the coprecipitation process.

Keywords

CoTi-substituted barium M-type ferrite / Co-dump copricipitation / synergetic coprecipation effect / coordination effect

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