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

The sintering of ferrite powders prepared by a hydrothermal treatment of st arting oxides was studied in comparison with conventional pre-sintered powd ers. Two hydrothermal powders were prepared, one with a similar degree of c onversion 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 h igh degree of conversion into MnZnFe2O4. In the first powder, non-homogenei ty caused primarily by the agglomeration of the Mn-rich particles (Mn3O4 an d ZnMn2O4) resulted in the formation of Kirkendall porosity, which signific antly influenced the densification. process. (C) 2001 Elsevier Science Ltd. All rights reserved.