Development of Thermodynamic Database of some Fe-based Alloy Systems and Its Application in the Design of Amorphous Alloys

由于铁基非晶态合金具有高饱和磁感应强度、高导磁和低损耗等优异磁学性能，而成为非晶态合金研究领域的一个热点。目前，大部分非晶态合金材料的制备研究主要采用“炒菜法”，但这会浪费大量的人力、物力，并且研发效率低、研发周期长。相图计算在材料的研究设计方面具有重要的指导作用，并且成为研究比较活跃的领域之一。铁基合金热力学数据库的建立将为铁基非晶态合金的设计和开发提供有效的指导作用。 在本研究中主要针对部分铁基合金（Fe-B-C-Mo-Cr-W-RE-Ag）体系进行展开研究，利用相图计算的方法，对Fe-B-C-Mo-Cr-W-RE-Ag体系中的部分二元系进行热力学优化，初步建立Fe-B-C-Mo-Cr-...Fe-based amorphous alloys are been paied much attention due to its excellent magnetic properties and considered to be a hotspot in the field of amorphous alloys. At present, most of amorphous alloys are usually obtained by the method of “try and error”, which squanders manpower and material resources. CALPHAD (CALculation of Phase Diagrams) method, which is a powerful tool to cut down on cost and ...学位：理学博士院系专业：材料学院材料科学与工程系_无机化学学号：1912005140304

Preparation of Nano-Titanium Dioxide Films and the Effects of Morphology and Properties by Doping Metal Ions

中文摘要近年来，随着全球工业化进程的迅速发展，环境问题日趋严峻。各国都将环境污染治理作为头等大事，纷纷投入巨资用于环境净化材料和环境污染治理技术等方面的研究，其中光催化消除和降解污染物成为最活跃的一个研究方向。利用二氧化钛的光催化氧化和亲水性，可以开发出新型的自清洁材料，并有着广泛的应用前景。本实验采用溶胶－凝胶法制备了掺杂Mg2+和Li+的TiO2薄膜。采用SEM、UV－Vis、XRD、XPS、IR等手段系统的对薄膜和粉末样品进行表征，并对掺杂前后TiO2薄膜亲水性能和光催化降解甲基橙溶液进行研究。主要研究进展及成果如下：1.在紫外光的照射下，TiO2薄膜表现了明显的亲水性，且对低浓度甲基橙...Abstract In recent years, with the expanding of global industrialization, the problem of environment pollution is more and more serious. A lot of researches on this problem have been performed by chemists, physicists, and chemical engineers. Among them, semiconductor photocatalysis is a promising technology that has a variety of application in environmental system such as air purification, w...学位：工学硕士院系专业：化学化工学院材料科学系_材料学学号：20023602

Low-temperature Preparation of Anatase TiO_2 Powders by Hydrothermal Method

[中文文摘]以钛酸四丁酯为前驱体,采用热液法在低于100℃的条件下制备了纳米晶TiO2粉体。运用DSC、XRD和HRTEM对所获得的TiO2粉体进行表征。XRD结果表明:所得到的TiO2粉体都是锐钛矿相,颗粒大小随着热液处理温度(60～100℃)的升高而增大,由Scherrer公式计算,其粒径介于4.8～6.9nm。同时,研究了所获TiO2粉体在紫外光下降解亚甲基蓝的性质。[英文摘要]Nanocrystalline TiO2 in the anatase phase has been obtained by hydrothermal method with tetrabutyl titanate below 100 ℃. The synthesized powders were characterized by differential scanning calorimetry (DSC), X-ray diffraction (XRD), and high resolution transmission electron microscope (HRTEM). XRD results show that the synthesized powders are all anatase. The grain size of the powders increases with the increment of the hydrothermal temperature from 60 degrees to 100 degrees, calculated grain size is from 4.8 to 6.9 nm by Scherrer method. The samples were investigated for the photodegradation properties of methylene blue (MB) solutions exposed to UV light illumination

RE-X二元合金相图的热力学数据库

利用CALPHAD方法,采用亚正规溶体模型、亚点阵模型以及理想气体模型来描述RE-X(Ag,Bi,Cr,Mn,Mo,V,Zn)中二元系各相的Gibbs自由能,并结合相平衡及热力学性质的实验结果,对Ag-RE(RE:Sc,Y,Nd,Sm,Gd,Tb,Ho,Er)、Bi-RE(RE:Nd,Tm,Er,Ho,Pr,Gd)、Cr-RE(RE:Ce,Nd,Sm,Lu)、Mn-RE(RE:Pr,Nd,Sm,Eu,Tb,Dy,Ho,Er,Tm,Yb,Lu)、Mo-RE(RE:Sc,Y,La,Ce,Pr,Nd,Sm,Eu,Tb,Dy,Ho,Er,Tm,Yb,Lu)、V-RE(RE:La,Ce,Pr,Nd,Ho,Lu)和Zn-RE(RE:Y,Ce,Pr,Nd,Sm)各二元系相图进行热力学优化与计算。计算结果与实验数据取得很好的一致性,并结合其他相关稀土二元系相图热力学计算,初步建立部分稀土二元合金相图的热力学数据库。该热力学数据库可以提供相平衡及热力学性质等多种信息,为外推计算稀土多组元体系的相平衡提供理论基础,并为高性能稀土合金材料的设计及制备提供重要的理论指导

Effects of Mg~(2+) Doping on Polymorphic Transition of TiO_2 Powders and Mechanism

[中文文摘]取钛酸丁酯、无水乙醇和硝酸镁为原料,采用溶胶-凝胶法制备掺杂不同量Mg2+的TiO2粉末,用XRD、TEM、TG-DTA对粉末的晶体结构、晶粒大小和形貌进行表征,并研究了TiO2在锐钛矿型和金红石型之间的的晶型转变过程.结果表明:粉末的平均粒径为纳米级,当物质的量分数x(Mg2+/Ti4+)=1.0%,粉末平均粒径由60 nm左右减为40 nm左右;Mg2+的掺入延缓了TiO2由锐钛矿型向金红石型的转变,且随着Mg2+掺入量的增加,晶型转变越不容易发生,当物质的量分数x(Mg2+/Ti4+)=2.0%时,Mg2+在TiO2中的固溶度已经达到饱和,XRD谱图开始出现MgTi2O5的特征峰.分析了Mg2+的掺杂阻碍了TiO2由锐钛矿型向金红石型转变的原因.因此,掺杂适当量Mg2+有利于制备热稳定性比较高的锐钛矿型粉末.[英文文摘]TiO_2 powder which was doped with Mg~(2+) at different mole percent of x(Mg~(2+)/Ti~(4+)) was prepared by sol-gel routing and using Ti(OC_4H_9)_4,C_2H_5OH and Mg(NO_3)_2 as the raw materias.The structure size and appearance of powders were characterized by XRD,TEM and TG-DTA,and its polymorphic transition between anatase and rutile of TiO_2 crystal type was also studied.The experimental results show that the average particle sizes of powders are in nanometer scale and the particle size at a mole percent of x (Mg2 + / Ti4 + ) = 1. 0 % reduces to about 40nm while the particle size of TiO2 powder without Mg2 + is about 60nm;When the mole percent of x (Mg2 + / Ti4 + ) = 2. 0 % ,the solubility of Mg2 + in TiO2 reaches it s saturation and the XRD spect rum of the powder has the character spect rum of MgTi2O5 ;Mg2 + doping can retard the t ransition of TiO2 f rom anatase to rutile and the retarding effect is enhanced with increment of mole percent of x (Mg2 + / Ti4 + ) ; The reason for the retarding effect is also analyzed; Therefore ,proper mole percent of x (Mg2 + / Ti4 + ) is useful to prepare TiO2 powders of anatase which has higher thermo-stability.福建省自然科学基金(E0310005); 武汉理工大学硅酸盐材料工程教育部重点实验室开放课题基金(2002)

Influence of Interface Diffusion between Al Substrate and TiO_2 Film on Photocatalytic Activity

[中文文摘]以钛酸四丁酯为前驱体,采用溶胶.凝胶法在铝基板表面制备了纳米晶TiO_2薄膜.运用XRD、SEM和XPS对制得的薄膜进行表征,并测试了薄膜光催化降解亚甲基蓝(MB)的活性.结果表明,TiO_2薄膜样品在450℃焙烧30 min后,晶粒排列比较致密,粒径为10-20 nm,并与铝基板紧密结合;薄膜与铝基板发生了明显的界面扩散,薄膜中的Al元素来自铝基板的界面扩散,且界面层很宽,扩散层厚度约为75 nm;界面扩散的发生直接导致了TiO_2薄膜的光催化活性下降.但随着薄膜厚度增加,铝基板对TiO_2薄膜降解亚甲基蓝催化活性的影响不断减小.[英文文摘]TiO_2 nano-crystalline films on Al substrate were prepared from tetra-n-butyl titanate by sol-gel method. The synthesized TiO_2 films were characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM)and X-ray photoelectron spectroscopy(XPS).The photodegradation activity of methylene blue(MB)solutions under UV irradiation was studied.The results indicated that the TiO_2 particles could be built up from crystallites ranging from 10 nm to 20 nm and had a dense bonding.The interface diffusion between TiO_2 and Al substrate takes place at calcination temperature of 450 C for 30 min and Al element diffuses into Tio 2 film from Al substrate, film from Al substrate,forming a diffusion layer with a thickness of about 75 nm.The interface diffusion between Tio 2 and Al subsrate leaded to the inferior photocatalytic activity.The influence of Al substrate on photodegradation activity of MB solutions became less and less as the thickness of the thin film increased.国家杰出青年科学基金(50425101

高增益偏振不灵敏InGaAs/InP体材料半导体光放大器

采用三元InGaAs体材料为有源区,通过直接在InGaAs体材料中引入0.20%张应变来加强TM模的增益,研制了一种适合于作波长变换器的偏振不灵敏半导体光放大器(SOA).在低压金属有机化学气相外延(LP-MOVPE)的过程中,只需调节三甲基Ga的源流量便可获得所要求的张应变量.制作的半导体光放大器在200 mA的注入电流下,获得了50nm宽的3 dB光带宽和小于0.5dB的增益抖动;重要的是,半导体光放大器能在较大的电流和波长范围里实现小于1.1dB的偏振灵敏度.对于1.55μm波长的信号光,在200 mA的偏置下,其偏振灵敏度小于1 dB,同时获得了大于14dB光纤到光纤的增益,3 dBm的饱和输出功率和大于30 dB的芯片增益.用作波长变换器,可获得较高的波长变换效率.进一步提高半导体光放大器与光纤的耦合效率,可得到性能更佳的半导体光放大器