共沉淀法合成Zn掺杂Co2-Y平面六角铁氧体粉的热力学分析

通过对 Me(Ba2+,Zn2+,Co2+,Fe3+)-CO32--NH3H2O体系进行热力学分析,得到不同的总碳浓度(cc)和总氮浓度(cN)时各金属离子总浓度(e,t曲与pH值关系,由此确定4种金属离子共沉淀完全的pH值范围.热力学分析表明:以Na2CO3和NH3·HzO作沉淀剂,用共沉淀法合成Zn掺杂Co2-Y平面六角铁氧体粉时,体系pH值由Ba2+和Zn2+沉淀完全的酸度条件决定,而两者取决于cc和cN的相对关系;当Cc＞1.000 mol·L-1、cN＜0.100 mol·L-1时,控制pH值在8～12范围内,即町确保共沉淀完全.

Thermodynamic Analysis on Preparation of Zinc Doped Co2-Y Planar Hexagonal Ferrite Powder by Chemical Co-precipitation Method

The pH-dependence of c_Me under various total carbon concentration c_C and total nitrogen concentration c_N in the Me-CO₃^2--NH_3-H₂O system were presented by thermodynamic analysis, and the co-precipitation window of Ba²⁺, Zn²⁺, Co²⁺ and Fe³⁺ was obtained at a suitable pH value. The results show that the co-precipitation window to prepare zinc doped Co₂-Y planar hexagonal ferrite powder is mainly controlled by the pH value for completely precipitation of Ba²⁺ and Zn²⁺ in co-precipitation process, and the precipitants are Na₂CO₃ and NH₃·H₂O, while the field of co-precipitation of Ba²⁺ and Zn²⁺ is determined by the reciprocal ship of c_C and c_N. In this system, when c_C value is greater than 1.000 mol·L^-1, and c_N value is smaller than 0.100 mol·L^-1, the four kinds of metal ions can be completely co-precipitated in pH value range from 8 to 12.