摘要
使用电熔镁砂、板状刚玉和分析纯氧化铁为原料,在1550℃埋石墨条件下高温烧成直径为20 mm厚10 mm的试样。使用X射线衍射仪分析试样的物相组成,使用Highscore Plus软件拟合试样中物相的衍射峰,根据特定晶面的晶面间距计算镁铁铝复合尖晶石的晶格常数和晶胞体积;用重铬酸钾容量法测试试样中氧化亚铁的含量;用扫描电子显微镜分析试样的微观结构;进行热力学计算阐述了镁铁铝复合尖晶石的生成机理。结果表明:制备的两种不同形貌的镁铁铝复合尖晶石,其晶格常数和晶胞体积均比标准卡片中MgO·Al_2O_3的大且其XRD谱中主强峰向左偏移;少量的MgO和Al_2O_3被C还原生成镁蒸气和铝蒸气,与CO和O_2发生气相沉积反应生成了针状MgO·Al_2O_3,高温下的液相促进了Al_(15.99)Mg_(7.64)Fe_(0.37)O_(32)相的生成。大量MgO与Al_2O_3反应生成了粒状MgO·Al_2O_3,Fe2+和Fe3+扩散进入MgO·Al_2O_3晶体内生成了Mg_(8.13)Al_(14.25)Fe_(1.13)O_(32)相;用重铬酸钾容量法测出,试样中FeO的含量为2.38%。
Mg-Fe-Al composite spinel was synthesized via carbon thermal reduction method at1550℃ with a size of Ф20 mm × 10 mm. The phase composition and the microstructure of the prepared composite spinel was characterized by X ray diffractometer and scanning electron microscopy respectively. The lattice constant and the unit cell volume of the Mg-Fe-Al composite spinel were calculated by combining the interplanar spacing of the specific crystal plane. Potassium dichromate volumetric method was used to determine the content of ferrous oxide in the composite spinel. Results show that two kinds of MgFe-Al composite spinel with different morphology were produced,of which the lattice constant and unit cell volume are larger than those presented in standard cards for MgO·Al2O3 and the main peaks of which shift to the lower angle side. A small amount of MgO and Al2O3 were reduced by C forming Mg-and Al-vapor, which then react with CO and O2 depositing as acicular MgO·Al2O3. The presence of liquid phase at high temperature promoted the formation of Al15.99Mg7.64Fe0.37O32 phase. A large amount of MgO and Al2O3 reacted directly to form granular MgO·Al2O3, Fe^2＋ and Fe^3＋ diffused into MgO·Al2O3 crystallites to form Mg8.13Al14.25Fe1.13O32 phase. The content of FeO in the composite spinel was 2.38% measured by potassium dichromate volumetric method.
作者
王彦惠
陈树江
李国华
田琳
孙丽杰
WANG Yanhui;CHEN Shujiang;LI Guohua;TIAN Lin;SUN Lijie(College of High Temperature Materials and Magnesium Resource Engineering, Liaoning University of Science and Technology, Anshan 114051, China)
出处
《材料研究学报》
EI
CAS
CSCD
北大核心
2018年第5期365-370,共6页
Chinese Journal of Materials Research
关键词
无机非金属材料
镁铁铝复合尖晶石
碳热还原法
镁铝尖晶石
重铬酸钾容量法
晶格常数
inorganic non-metallic materials
magnesium-iron-aluminum composite spinel
arbon thermal reduction method
magnesia-alumina spinel
potassium dichromate volumetric method
lattice constant
