Bi4Ti3O12粉体的性能、应用及制备

介绍了钛酸铋粉体的结构、性能及应用，并重点介绍了钛酸铋粉体的几种主要制备方法。     

可见光响应的铋系光催化剂研究进展

可见光响应的铋系光催化剂在降解和矿化难降解有机物方面具有良好的可见光光催化活性,介绍了卤氧化铋、钨酸铋、钛酸铋、钒酸铋、钼酸铋、复合型铋系可见光光催化剂的研究动态和主要成果,并从机理上作了解释,同时指出未来研究将集中在新型可见光光催化剂的开发和催化机理的研究方面.     

微波水热法制备含氟钛酸铋系光催化剂及光催化性能研究

以Bi(NO3)3·5H2O和(NH4)2TiF6为原料,采用微波水热法在120℃~220℃反应1h得到了具有不同形貌的粉体.借助XRD、FE-SEM和EDS等分析手段对粉体的组成和形貌进行了表征,并以罗丹明B溶液为目标降解物,研究了200℃下所得粉体的光催化性能.结果表明:所得粉体是一种新型的F掺杂钛酸铋粉体,其中Bi、Ti、O、F的原子比例约为6∶11∶27∶8;随着反应温度的升高,粉体形貌从球形向六棱短柱状转变;紫外光照射下粉体具有较好的降解罗丹明B溶液的能力.     

固相法和水热法制备BNT无铅压电陶瓷及其性能表征

采用固相法和水热法成功制备出钛酸铋钠（Bi0.5Na0.5TiO3,简写为BNT）粉体,并利用此粉体烧结出致密的BNT陶瓷.用XRD、SEM分别对粉体和陶瓷的相组成、粒度、显微结构等进行了表征,并检测了其不同烧结温度下的线收缩率和相对体积密度.固相法所制备的BNT陶瓷具有优良的压电性能,其压电常数d33高达80 pC/N,而机电耦合系数kp也达到了26%.利用水热法只需在160℃下保温16 h就合成了具有单一钙钛矿结构的BNT粉体,其粒径为0.6-1μm.     

BIT/PLZT/BIT多层铁电薄膜的I-V特性研究

为了有效阻止锆钛酸铅镧（PLZT）与半导体界面发生反应和互扩散，根据锆钛酸铅镧和钛酸铋（BIT）各自的铁电性能，采用脉冲准分子激光淀积（PLD）方法制备了BIT／PLZT／BIT多层结构铁电薄膜，测量和分析了它的I-V特性曲线．结果表明，这种结构吸收了锆钛酸铅镧和钛酸铋的优点，提高了铁电薄膜的铁电性能，为进一步研究薄膜的存储特性提供了基础．     

钛酸铅(PT)粉体的快速合成与表征

选用甘油为溶剂,以醋酸铅、钛酸四丁酯为基体原料,采用金属有机物热分解(MOD)法,合成了铁电钛酸铅(PT)粉体,并通过XRD、TG/DTA、IR、SEM等手段表征了合成粉体的组成以及形貌.结果表明,合成的PT粉体纯度高,颗粒细小均匀.     

钛酸铅（PT）粉体的快速合成与表征

选用甘油为溶剂,以醋酸铅、钛酸四丁酯为基体原料,采用金属有机物热分解(MOD)法,合成了铁电钛酸铅(PT)粉体,并通过XRD、TG/DTA、IR、SEM等手段表征了合成粉体的组成以及形貌.结果表明,合成的PT粉体纯度高,颗粒细小均匀.     

自制大分子钛酸酯表面改性剂对纳米Si_3N_4粉末的表面化学修饰

采用自制的大分子钛酸酯表面改性剂对纳米Si3N4进行表面包覆处理,对处理前后的纳米Si3N4粉末运用TEM、FT-IR、TGA等进行了表征。结果表明,大分子钛酸酯表面改性剂包覆在纳米Si3N4粉体表面,并与其发生了化学作用,有效地阻止了纳米Si3N4粉体的团聚,在大分子钛酸酯表面改性剂质量分数为11%时,纳米Si3N4粒子粒径较小,粒径分布最窄。     

Bi2WO6粉体光催化剂的制备方法及研究进展

光催化技术因其在环境污染净化、能源再生方面的应用前景而引起了广泛关注,新型光催化剂钨酸铋因其具有可见光催化活性成为了光化学领域的研究热点之一．作者简述了Bi2WO6粉体光催化剂的结构及光催化性,详细介绍了一些Bi2WO6粉体的制备方法,总结了Bi2WO6粉体光催化剂今后的研究方向与热点,可为有关人员提供参考．     

金属有机物热分解法制备Bi4Ti3O12薄膜的工艺研究

由硝酸铋和钛酸丁酯原料出发,采用金属有机物热分解法（ＭＯＤ）制备了铁电钛酸铋薄膜;对先体溶液进行了红外光谱和差热分析,研究了旋转甩胶工艺和烧结温度与膜厚的关系,由Ｘ射线衍射和扫描电子显微镜分析了薄膜的物相和断面形貌,得到：在４５０￣６５０℃较低烧结温度下即可合成钛酸铋致密多晶薄膜。薄膜厚度随烧结温度增高而减小,在５００￣６５０℃范围内基本呈线性,温度每增高５０℃膜厚减小约５％。     

Effect of La Doping on Microstructure and Ferroelectric Properties of Bi4Ti3O12 Thin Films Prepared by Sol-gel Method

The Bi4Ti3O12 and Bi3.25La0.75Ti3O12 thin films were prepared on the Pt/Ti/SiO2/Si substrate using the sol-gel method. The effect of La doping on the microstructure and ferroelectric properties of Bi4Ti3O12 films were investigated. Both the Bi4Ti3O12 and Bi3.25La0.75Ti3O12 thin films exhibited typical bismuth layered perovskite structure. The 2Pr (remanent polarization) value of Bi3.25La0.75Ti3O12 thin films is 18.6 Μc/cm2, which is much larger than that of Bi4Ti3O12 thin films. And the Bi3.25La0.75Ti3O12 films show fatigue-free behavior, while the Bi4Ti3O12 thin films exhibit the fatigue problem. The mechanism of improvement of La doping was discussed.     

溶胶-凝胶法制备（Nd,Bi）_4Ti_3O_（12）铁电薄膜

采用溶胶-凝胶法在Pt/Ti/SiO2/Si基片上制备了（Nd,Bi）4Ti3O12薄膜。将薄膜于空气中分别进行每1层、每2层、每3层500℃预退火10 min,最后于氮气氛中680℃退火30 min。结果表明：预退火工艺对薄膜的结构和铁电性能都有影响：每一层预退火处理的薄膜具有较大的剩余极化值和最小的矫顽场（2Pr=47.8μC/cm2,2Ec=254 kV/cm）。所有薄膜都呈现良好的抗疲劳特性。     

Ferroelectric properties of Bi_(3.25)La_(0.75)Ti_(3)O_(12) thin films prepared by sol-gel method

The Bi3.25La0.75Ti3O12 thin films were fabricated on the Pt/Ti/SiO2/Si substrates using sol-gel method. The structure and morphology of the films were characterized us-ing X-ray diffraction and atomic force microscopy. The thin films showed a perov- skite phase and dense microstructure. The 2Pr and 2Vc of the Bi3.25La0.75Ti3O12 thin films annealed at 700℃ were 18.6 μC/cm2 and 4.1 V, respectively, under an applied voltage 10 V. After the switching of 1×1010 cycles, the Pr value decreased to 90% of its pre-fatigue values. The films showed good insulating behavior according to the test of leakage current. The dielectric constant and the dissipation factor of the Bi3.25La0.75Ti3O12 thin films were about 176 and 0.046 at 1 kHz, respectively.     

高取向钛酸铋陶瓷铁电和介电性能研究

采用改进的固相烧结法，制备出具有高c轴取向的Bi4Ti3O12铁电陶瓷样品，从对样品的铁电、介电测量中可以看出，样品的取向性对样品的铁电性能（剩余极化、矫顽场）、漏电流、介电性能等都产生了影响。     

Ab Initio Study of Doping Mechanisms in Ba TiO_3-BiYO_3

A density functional plane-wave pseudopotential method is used to study the doping mechanisms of impurity defects(Bi_(Ba),Y_(Ti)) in BaTi O_3-BiYO_3. Single Bi_(Ba) and Y_(Ti) impurities have little structure distortion. Bi forms ionic bond with nearby O atom in single Bi impurity, Y formed [YO_6] octahedral in single Y impurity. However, in the co-doped Bi_(Ba) and Y_(Ti) structure, Bi formed three valence bonds with nearby O atom, which causes the large structure distortion. The doped ion makes the mobile of Ti~(4+) difficult and loss local ferroelectricity, which will broaden the dielectric constant temperature curve and increase the temperature stability of BaTiO_3 ceramic matrix.     

Bi4Ti3O12陶瓷及其A和B位掺杂的介电研究

测量了Bi4Ti3O12(BTO)陶瓷及其A和B位掺杂的系列材料介电损耗。在温度损耗谱上观察到一损耗峰，通过氧处理和内耗等相关实验手段，证实该峰（PI）是与氧空位有关的弛豫峰。同时观察该峰随不同掺杂类型的变化，分析了BTO陶瓷B位掺杂对铁电性的影响。     

Domain structure and defects of highly ordered Bi_4Si_3O_(12) micro-crystals

Highly ordered Bi4Si3O12 micro-crystals were prepared at normal atmosphere. Phase identification of the prepared crystals was accomplished by X-ray diffractometer (XRD). Domain structure and defects were characterized by environmental scanning electron microscopy (ESEM). XRD shows that the obtained micro-crystals are of eulytite structure with chemical formulation of Bi4Si3O12. A highly ordered growth pattern is confirmed due to the faster growth of the {124} faces than that of the {204} faces by ESEM. The ...     

Effects of carbon sources on electrochemical performance of Li_4Ti_5O_(12)/C composite anode materials

Li4Ti5O12/C composite materials were synthesized by two-step solid state reaction method with glucose,sucrose,and starch as carbon sources,respectively.The effects of carbon sources on the structure,morphology,and electrochemical performance of Li4Ti5O12/C composite materials were investigated by SEM,XRD and electrochemical tests.The results indicate that carbon sources have almost no effect on the structure of Li4Ti5O12/C composite materials.The initial discharge capacities of the Li4Ti5O12/C composite materials are slightly lower than those of as-synthesized Li4Ti5O12.However,Li4Ti5O12/C composite materials show better electrochemical rate performance than the as-synthesized Li4Ti5O12.The capacity retention(79%) of the Li4Ti5O12/C composite materials with starch as carbon source,is higher than that of Li4Ti5O12/C composite materials with glucose and sucrose as carbon source at current rate of 2.0C.     

CaMnO3热电材料的低温烧结研究

采用固相反应法制备CaMnO3粉末,加入Bi2O3混合、压块后,在900％烧结12h得到样品,并对样品的物相、组织和热电性能进行了测试分析。结果表明：制备出的热电材料是单相的CaMnO3,加入Bi2O3后没有形成可观测的第二相;随着Bi2O3加入量的增加,样品的平均电导率增大,温差电势减小;平均电导率随温度的增加而增加,呈半导体特性,温差电势随温度的增加而增大;加入Bi2O3促进了烧结,降低了烧结温度,改善了材料的热电性能。