THE FORMATION OF NIZN FERRITE FROM MIXED HYDROXIDES

The formation of Ni0.5Zn0.5Fe2O4 from mixed hydroxides was investigated by XRD, Mossbauer spectroscopy and magnetic measurement. For the synthesis of the ferrites mentioned not only the hydroxides Ni(OH)2, Zn(OH)2, FeOOH precipitated under defined conditions were used but also a mixture of ZnFe2O4 (obtained by coprecipitation) with aliquot Ni(OH)2 and FeOOH quantities, aged in aqueous environment. Subsequently, the powders isolated are tempered. The mixed ferrite Ni0.5Zn0.5Fe2O4 is directly formed from the hydroxide products without other oxidic phases being detectable. But no homogeneous distribution of Ni2+- or Zn2+-ions in the spinel is obtainable even after tempering at 500-degrees-C. On the contrary, the mixed ferrites arises only to a small extent from the ZnFe2O4, Ni(OH)2 and FeOOH mixture. Mainly, NiO and alpha-Fe2O3 are formed. The dependence of processes is discussed in the mixed ferrite phase formation on synthesis, ageing and tempering conditions.