【摘要】 用溶胶-凝胶(sol-gel)法制备了Li0.5-0.5xZnxMnaFe2.5-0.5x-aO4(0.1<x<0.6)铁氧体纳米粉。比较了分别以柠檬酸和聚乙烯醇(PVA)为络合剂时粉料的X射线衍射(XRD)谱。XRD分析表明,以柠檬酸为络合剂制备的粉料粒度为6~22nm,生成尖晶石的固相反应从400℃开始,到600℃完成;以PVA为络合剂的粉料的XRD谱为复杂双相结构。SEM形貌照片和烧结收缩曲线表明,不同活性粉料对烧结致密化和晶粒生长过程有明显影响。在纳米粉的低温烧结过程中发生了晶粒异常生长。选择较少(0.25mol%)的Bi2O3添加量和适当工艺参数便可以实现Ts≤900℃的低温烧结。给出了880+20℃烧结样品的铁磁共振线宽ΔH和饱和磁化强度Ms随Zn含量的变化。更多还原

【Abstract】 The Li0.5-0.5xZnxMna Fe2.5-0.5x-aO4 (0.1<x<0.6) ferrites were prepared by sol-gel method. The XRD spectra of two kinds of powders prepared by the chelating agent of citric acid and polyethylene alcohol (PVA), are compared. The XRD spectra of the powders from the citrate precursor show that the formation of spinel phase LiZn ferrites begins from 400℃ and ends at 600℃ with particle size of 6-22 nm. The powders prepared by PVA chelating agent exhibit complicate XRD spectra involving two phases. The curves of sintering shrinkage versus temperature and the SEM photographs of samples sintered at temperature from 800 to 880℃ are illustrated for the powders (L54, L03) having different activity because of different processes, which demonstrats that the sintering behaviors of the LiZn ferrites powders depend strongly on the activity of the powder. The abnormal grain growth was observed on SEM photographs. The sintering temperature decreases with increasing Bi2O3 content, and the sintering at temperature Ts bellow 900℃ can be achieved by using 0.25mol%Bi2O3. The drawing of the saturation magnetization Ms and the ferromagnetic resonance linewidth ΔH versus zinc content was shown for the specimens of Li0.5-0.5xZnxMna Fe2.5-0.5x-aO4 ferrite sintered at 880+20℃.更多还原