【摘要】 采用燃烧合成法制备了MnFe2 O4铁氧体粉体。研究了铁氧体的转化率、燃烧波速率与放热反应控制系数、氧压力之间的相互关系。通过XRD和M ssbauer谱等手段对产物的物相组成和结构进行了分析。结果表明 ,以燃烧合成方法制备MnFe2 O4粉体的转化率较低 ( 35 %～ 5 0 % ) ,产物存在较多的晶格缺陷 ,并且存在部分亚稳相 ,如FeMnO3 。亚稳相的存在增加了粉体的烧结活性。氧压力和放热反应控制系数对MnFe2 O4相的转化率影响较小。随氧压力的增加 ,转化率和燃烧波速率均有所增加 ,而且放热反应控制系数较小时 ,随氧压力增加的幅度更为明显。 12 0 0℃下在空气和水中对产物进行淬火 ,均可得到结构较完整的单相尖晶石型MnFe2 O4,且阳离子趋向反型分布 (反分布率α≈ 0 .7)。更多还原

【Abstract】 The spinel MnFe 2O 4 ferrite powders were prepared by the combustion synthesis method. The dependences of the degree of the ferritization and the combustion wave velocity on the coefficient of the mixture exothermicity k and the oxygen pressure were discussed in detail. The phase composition of the combustion products were also studied by XRD and Mssbauer. The results show that the precent conversion to MnFe 2O 4 ferrite powders is low (between 35% and 50%) and there are many defects in the structure of the crystal lattice. The combustion products consist of the metastable phases such as MnFeO 3 which lead to the higher sintering reactivity of the products. The oxygen pressure and k value have less influnce on the degree of ferritization. Both the degree of the ferritization and the combustion wave velocity increase with the increase of the oxygen pressure, moreover, the extent of the increase is more obvious when the k value is lower. The single spinel phase MnFe 2O 4 powders, which have predominantly inverse cation distribution, are obtained by quenching the products at 1200℃ into the air or the water.更多还原