Preparation and characterization of the BaFe12O19 by co-precipitation method

• Main Authors: Wei-Ying Wang, 王唯穎
• Other Authors: 余宣賦
• Format: Others
• Language: zh-TW
• Published: 2009
• Online Access: http://ndltd.ncl.edu.tw/handle/33074852263765785017

碩士 === 淡江大學 === 化學工程與材料工程學系碩士班 === 97 === Hexagonal barium ferrite (BaFe12O19) powders with superior magnetic properties were synthesized using a modified co-precipitation method. One hundred milliliters of the aqueous solution, containing the stoichiometric amounts of barium and iron nitrates to form BaFe12O19, were added into the 400-mL solution of acetone and ammonia, which was controlled at 30 C, to undergo precipitation reaction for 3 h. The relative amounts of acetone and ammonia in the solution were varied according to R (define : volume of ammonia used/the total volume of the solution of acetone and ammonia) and R ranged from 0 to 1. After being centrifugally separated, the collected particles were dried at 300 C, followed by calcining at temperatures (T) between 600 ~ 900 C. The calcined particles were then characterized using x-ray diffractometer, infrared spectrometer, scanning electron microscope, transmittance electron microscope, and vibrating sample magnetometer. The experimental results indicated that crystalline BaFe12O19 was able to be formed at 650 C but the specimen still contained some BaCO3 and a-Fe2O3. To obtain pure BaFe12O19 powder, calcining the precipitates at 800 oC were required. When R = 0.6 and T = 800 oC, the obtained BaFe12O19 powder exhibited saturated magnetization of 67.7 emu/g and coercive force of 4.84 kOe.