采用二次化学共沉淀法制备出六角或近六角片状BaFe12O19, 其颗粒径向尺寸和径厚比分别为0.4--2 μm和4--20。通过XRD、FTIR、TG/DTA及SEM/EDS分析技术研究了片状BaFe12O19的形成历程。结果表明: 前驱体为非晶态BaCO3、低结晶态Fe(OH)3和晶态α--Fe2O3包覆原料BaFe12O19复合物; 前驱体在焙烧过程中经过 Fe(OH)3脱水、BaCO3分解反应、中间相α--Fe2O3和BaO反应得到终产物BaFe12O19。基于形成历程, 六角片状BaFe12O19较原料BaFe12O19表现出显著提高的颗粒径向尺寸和径厚比、较高的纯度和略低的结晶有序程度, 进而表现出明显提高的矫顽力、略低的饱和磁化强度和剩余磁化强度。
Hexagonal plate–shaped BaFe12O19 ferrites are prepared by the second chemical coprecipitation method using co-precipitation synthesized–BaFe12O19 ferrites as template materials. The particle size of the prepared plate-shaped BaFe12O19 ferrites is in the range of 0.4-2 μm with a diameterto-thickness ratio of 4–20. The synthesis process is studied by using XRD, FTIR, TG/DTA, SEM/EDS. It is shown that the precursor was a composite of BaFe12O19 coated by non–crystalline BaCO3, low-crystalline Fe(OH)3 and crystalline α–Fe2O3. During calcinations,the precursor experiences dehydration of Fe(OH)3, decomposition of BaCO3, and the reaction of α–Fe2O3 and BaO, and finally produces BaFe12O19. The prepared plated–shaped BaFe12O19 ferrite presents a higher coercivity and lower saturation magnetization and remanence, owing to its higher purity, slightly poor crystallinity, larger radial size and diameter–length ratio.
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