Sintering of MnZn-ferrite powders prepared by hydrothermal reactions between oxides

The sintering of ferrite powders prepared by a hydrothermal treatment of starting oxides was studied in comparison with conventional pre-sintered powders. Two hydrothermal powders were prepared, one with a similar degree of conversion into spinel products as the pre-sintered powder but with a larger specific surface, and the other with a lower specific surface area and a high degree of conversion into MnZnFe2O4. In the first powder, non-homogeneity caused primarily by the agglomeration of the Mn-rich particles (Mn3O4 and ZnMn2O4) resulted in the formation of Kirkendall porosity, which significantly influenced the densification process.