Synthesis of Ni-Zn ferrite and its microstructure and magnetic properties

来源期刊：中南大学学报(英文版)2006年第6期

论文作者：阳征会 龚竹青 李宏煦 马玉天 杨余芳

文章页码：618 - 623

Key words：sodium jarosite ; hydrothermal synthesis; Ni-Zn ferrite;nanoparticle

Abstract: Nanometer Ni_0.5Zn_0.5Fe₂O₄ powders with spinel phase were prepared by the hydrothermal method using purified FeSO₄ solution from sodium jarosite’s slag as materials.The results show that the spinel phase of Ni_0.5Zn_0.5Fe₂O₄ powders begins to form at a relatively low temperature(130℃)and a shorter holding time(1 h)when pH=8.The crystallization kinetics equation at 200℃ is ln[-ln(1-x)]＝-0.78+0.95ln t.The growth activation energy of Ni_0.5Zn_0.5Fe₂O₄ grains is 41.6 kJ/moL in hydrothermal synthesis process.With the increase of sintering temperature,the density and diameter shrinkage of ferrite circulus increase,whereas its pores decrease.The results of magnetic measurements show that saturation magnetic flux density Bs increases and the coercivity Hc decreases with the increase of their sintering temperature.Magnetic parameters of all the investigated samples satisfy the character demand of high Bs,low Br and low Hc of soft magnetic ferrite materials.