Magnetic properties and microstructural characteristics of SrO·5.9Fe2O3 chemically modified with Si and Ca were investigated by changing experimental parameters such as additive composition, the ratio of Ca/Si, and sintering condition. A novel particulate coating method utilizing sol-gel reactions was used to uniformly incorporate the additives of Si and Ca. This method was very successful in obtaining homogeneous grain growth and fine grains. A sample containing the gel additives of 0.6 wt% SiO2 and 0.7 wt% CaO and sintered at 1200°C for 4 h was found to significantly suppress abnormal grain growth, resulting in submicron-sized grains and high density. A distinct grain boundary phase containing Si and Ca was observed by increasing the sintering temperature to 1250°C. The resultant microstructural characteristics favorably affected magnetic properties. For example, the chemically modified sample exhibited a higher coercivity of 3530 Oe compared to a value of 2050 Oe obtained for the sample without the additives. On the other hand, an increase in the ratio of Ca/Si or in sintering temperature tended to induce a large anisotropy during grain growth.
|Number of pages||3|
|Journal||Journal of Applied Physics|
|Issue number||8 II B|
|Publication status||Published - 1999 Apr 15|
All Science Journal Classification (ASJC) codes
- Physics and Astronomy(all)