Preparation of ultrafine barium ferrite powders by sol-gel technique

作者：He HY^*; Huang JF; Cao LY; Wu JP; Shen Q; Ma XB; Deng F

来源：Silicates Industriels, 2006, 71(3-4): 48-52.

• sol-gel
• two-step heat treatment
• barium ferrite powder
• preferred crystallization
• magnetic properties

Ultrafine barium ferrite magnetic powders have been synthesized successfully by sol-gel method The hydroxide precursor particles were formed in gel solution containing ethanol and water at a ratio of 1:135 and Ba2+ and Fe3+ cation at a ratio of 1.02:12 and NaOH as coprecipitation agent. The hydroxide precursor was preheated at 300 degrees C for 1h. Three hearing rates were adopted in a range of 300-900 degrees C. Preheated precursor was calcined at 800 degrees C and 900 degrees C for 3h XRD and SEM have been used to obtain detailed information on the crystallography of the calcined powders. The Xray-diffractometry revealed that ultrafine barium ferrite particles have been formed and the particles size is 47.0-51.3nm closing to the theoretical single-domain size, which ensure high coercivity for barium ferrite. The higher heating rate resulted in the increased crystallinity of particles and the preferred orientation of crystallization along c-axis, which can be expected to improve saturation magnetization. The results of SEM analysis are in agreement with that of XRD analysis.

• 出版日期2006-4
• 单位陕西科技大学