Ultrafine Mn-Zn ferrite powders were synthesized under mild hydrothermal conditions by precipitation from metal nitrates with an aqueous ammonia. R value (alkalinity) was introduced to adjust the amount of added ammonia. A method of controlling the desired compositions and crystallite sizes of synthesized powders was proposed in this paper. In addition, the effect of R value and hydrothermal time on powder characterization, such as the Mn/Zn ratio in spinel structure of synthesized powders, variation of X-ray diffraction angle of spinel ferrites, crystallite size and the loss ratio of Zn2+ for different starting suspensions during hydrothermal process, was also investigated. Powders upon hydrothermal treatment exhibited superior sinterability as compared to powders which were not subjected to hydrothermal treatment. High densities, 99.4-99.8% of theoretical densities, were obtained upon sintering green ferrite powders at relatively low temperature (900-950°C) in N2 atmosphere without any sintering aids.
All Science Journal Classification (ASJC) codes
- Ceramics and Composites
- Condensed Matter Physics
- Materials Chemistry