| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 1616666 | Journal of Alloys and Compounds | 2012 | 5 Pages |
The samples with small amounts of MnO2 (0, 0.5, 1.0, 1.5, 2.0, and 2.5 wt%, respectively) were prepared via ball-milling process and two-step sintering process from commercial powders (i.e. Fe2O3, NiO and MnO2). Microstructural features, phase transformation, sintering behavior and magnetic properties of Mn-doped NiFe2O4 composite ceramics have been investigated by means of scanning electron microscopy (SEM), differential thermal analyzer, X-ray diffraction (XRD), thermal dilatometer and vibrating sample magnetometer (VSM) respectively. The XRD analysis and the result of differential thermal analysis indicate that the reduction of MnO2 into Mn2O3 and the following reduction of Mn2O3 into MnO existed in sintering process. No new phases are detected in the ceramic matrix, the crystalline structure of the ceramic matrix is still NiFe2O4 spinel structure. Morphology and the detecting result of thermal dilatometer show that MnO2 can promote the sintering process, the temperature for 1 wt% MnO2-doped samples to reach the maximum shrinkage rate is 59 °C lower than that of un-doped samples. For 1 wt% MnO2-doped samples, the value of the saturation magnetization (Ms) and coercivity (Hc) is 15.673 emu/g and 48.316 Oe respectively.
► A two-step sintering process was adopted to prepare NiFe2O4 composite ceramics. ► In this work, the effect of MnO2 on the mechanism of promoting sintering for MnO2 in NiFe2O4 composite ceramics was investigated. ► The effect of MnO2 additive on magnetic properties of NiFe2O4 composite ceramics was also studied.
