Synthesis and properties of Tb~(3 ) isomultiligand complexes

Synthesis and properties of Tb~(3 ) isomultiligand complexes     

Deposition and photoluminescence of sol–gel derived Tb:Zn2SiO4 films on SiO2/Si

Tb³⁺ doped Zn₂SiO₄ films have been deposited on SiO₂ buffered Si wafers by sol–gel method. The structures of these films have been investigated with X-ray diffraction (XRD), atomic force microscopy (AFM), and scanning electron microscopy (SEM). The results revealed that these films were composed of nanometer-size grains with a Willemite structure and had smooth surfaces. Photoluminescence measurements of the films showed a strong emission from ⁵D₄ to ⁷F₅ at 544 nm. The blue emission from ⁵D₃–⁷F_j was depressed because of cross-relaxation effect. The decay kinetics of the ⁵D₄–⁷F₅ green emission was studied and a best fitting was obtained by a double exponential function. The lifetime of the excited ⁵D₄ state is estimated to be 5.2 ms.     

Thermodynamic assessment of the Ga–Sc and Ga–Tb systems

The Ga–Sc and Ga–Tb binary systems have been assessed with CALPHAD method. Liquid is treated as substitutional solution phase, of which the excess Gibbs energies are modeled by Redlich–Kister polynomial function. The binary intermetallic compounds are treated as stoichiometric phases. Thermodynamic parameters of various phases have been optimized and the calculated results are in reasonable agreement with experimental data.     

Al/Tb_(0.30)Dy_(0.70)Fe_(1.95)复合材料的制备与性能研究

采用真空粉末烧结法,制备了Al/Tb0.30Dy0.70Fe1.95复合材料,研究了该复合材料的物相、组织结构以及磁致伸缩性能,并对Al的加入量对复合材料的结构与性能的影响规律进行了探索.研究结果表明:烧结制备的Al/Tb0.30Dy0.70Fe1.95复合材料为多相结构,主要存在ReFe2、Al7ReFe5、Al2Re、Al3Re等相,随着Al的体积分数的增加,复合体中非GMM相渐渐增多,而GMM相则相应地减少,复合体内已不存在Al相;随着Al的体积分数的增加,复合材料的磁致伸缩系数λ起初略有上升,后明显下降,与纯GMM合金相比,Al/Tb0.30Dy0.70-Fe1.95复合材料的磁致伸缩性能均较差,当Al的体积分数为20%时,Al/Tb0.30Dy0.70Fe1.95复合材料的磁致伸缩系数约为合金的一半,为512×10-6;在GMM合金中适当增加廉价的Al元素后,可保持一定的磁致伸缩性能,还可以减少稀土等昂贵金属的含量,降低了成本.     

铽纳米颗粒掺杂烧结高性能NdFeB永磁的研究

分别采用物理气相沉积和快淬-氢爆工艺制备了Tb纳米粉和主相Nd_2Fe_(14)B磁性粉末, 研究了Tb纳米颗粒掺杂对烧结NdFeB永磁磁性能和微观结构的影响. 结果表明, 随着纳米Tb粉含量的增加, 磁体的矫顽力逐渐升高, 剩磁和磁能积则呈下降趋势. 显微组织研究表明, Tb元素富集在主相晶粒的边界层位置, 这种分布方式不仅有效地提高了磁体的矫顽力, 而且降低了Tb的添加量, 从而减小了Tb的添加对磁体剩磁及磁能积的负面影响.     

晶界扩散Tb对烧结Nd-Fe-B组织与磁性能的影响

用磁控溅射法在烧结Nd-Fe-B磁体表面沉积Tb金属薄膜并进行晶界扩散处理,对比经不同热扩散温度及时间处理后的磁体组织和磁性能变化.结果 表明,925℃×10 h+500℃×2 h为最佳晶界扩散工艺,可将磁体矫顽力提高到1630.9 kA· m-1,较原始磁体提升50％,同时剩磁和磁能积无明显下降,磁体仍具有较高的退磁...     

KCaPO4:Tb3+绿色荧光粉的发光特性

采用高温固相法合成了KCaPO4:Tb3+绿色荧光粉,并研究了材料的发光性质.KCaPO4:Tb什材料呈多峰发射,发射峰为437、490、545、587和623nm,分别对应Tb3+的5D3→F4和5D4→FJ=615,4,3跃迁发射,主峰为545nm;监测545nm发射峰,所得激发光谱由4f7 5d1宽带吸收(200...     

二-(2-乙基己基)膦酸(P_(229))萃取Tb,TmSCIEI

研究了P_(229)萃取剂从盐酸及硝酸溶液中的萃取。结果表明,P_(229)萃取Tb^(3+),Tm^(3+)的分配比D在硝酸介质中比在盐酸介质中大。获得在15—55℃下P_(229)萃取Tb^(3+),Tm^(3+)的热效应数据及温度函数。数据表明,由于ΔH>0,ΔS<0,反应主要依体系焓变促成。计算了萃取络合物的热分解反应动力学参数表观活化能E及反应级数。可信度>95％。     

稀土(铽)二元和三元配合物的合成及荧光性质

分别合成了稀土铽-N-苯基邻氨基苯甲酸、铽-N-苯基邻氨基苯甲酸-邻菲罗啉两种稀土二元及三元配合物。此外,采用溶胶-凝胶湿化学制备手段在SiO2凝胶玻璃中引入了铽-N-苯基邻氨基苯甲酸-邻菲罗啉三元配合物,对合成的配合物进行了表征,在紫外光激发下,它们均能发射铽离子的特征荧光。     

铽-N-苯基邻氨基苯甲酸的合成及荧光性质

采用共沉淀法制备了稀土铽的N-苯基邻氨基苯甲酸二元配合物,同时,采用溶胶-凝胶法制备了掺杂稀土铽的N-苯基邻氨基苯甲酸二元配合物的SiO2凝胶玻璃复合发光体,研究了合成的两种配合物的热稳定性及荧光性质。结果表明:在凝胶玻璃中合成的稀土二元配合物,其热稳定性明显提高,而其特征荧光基本保持不变。