摘要
采用固相烧结法,以Yb2O3、MoO3、Fe3O4为原料制备了Fe2-x Ybx Mo3O12(x=0,0.2,0.4,0.6,0.8,1,1.2,1.4,1.6,1.8,2)系列固溶体,并通过X射线衍射图样、Raman光谱、热分析以及膨胀系数测试对其结构、相变、吸水性及热膨胀性能进行了研究。结果表明Fe2-x Ybx Mo3O12当x≤0.4时是单斜相,当x≥0.6时是正交相,随着x值的增加Fe2-x Ybx Mo3O12材料的相变温度逐渐降低。Fe2-x Ybx Mo3O12含有的水分子可以分为两类,一类吸附在晶体表面对晶格振动没有影响,第二类进入晶体内部对晶格振动产生较大影响,导致负膨胀性质的消失,只有完全失去水分子后才表现负热膨胀性能。
Fe2-xYbxMo3O12（x=0,0.2,0.4,0.6,0.8,1,1.2,1.4,1.6,1.8,2） are synthesized with solid state method,and characterized for crystal structure,hygroscopicity and thermal expansion by X-ray diffraction,Raman spectroscopy,thermal analysis and dilatometer.The investigation shows that Fe2-xYbx Mo3O12 present monoclinic phase for x ≤0.4 and orthorhombic phase for x≥0.6.The phase transition temperature of Fe2-xYbx Mo3O12 decreases with increasing the x value.Fe2-xYbxMo3O12 possess two kinds of water molecule：one distributing on the surface of crystal has less effect on crystal vibrations;another entering inside of crystal has significant effect on lattice vibrations.The negative thermal expansion property can present only after complete release of the crystal water.
出处
《光散射学报》
北大核心
2013年第3期258-263,共6页
The Journal of Light Scattering
基金
国家自然科学基金(10974183
11104252)
郑州市创新团队(2011-3)
关键词
固溶体
相变
吸水性
热膨胀
solid solutions
phase transition
hygroscopicity
thermal expansion
