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.     

Grain dependence of ferroelectric domain switching on SrBi2Ta2O9 thin films observed by Kelvin probe force microscope

We have studied grain-shape dependence of Kelvin probe force microscopy of SrBi₂Ta₂O₉ thin films on epitaxial La_0.5Sr_0.5CoO₃/LaAlO₃ substrates. By changing the growth condition in pulsed laser deposition, we have grown the SrBi₂Ta₂O₉ thin films with various grain shapes. The shape and the orientation of SrBi₂Ta₂O₉ the thin films with various growth conditions have been analyzed by X-ray diffraction and scanning electron microscope. The large number of the long rectangular grains was observed accompanied with relatively larger (220) peaks than other peaks. From the Kelvin probe force microscope study, it has been observed that the long rectangular grains showed characteristics of easy ferroelectric domain switching at a low writing bias and weaker influence of surface charges.     

冷拔无铅含Bi易切削黄铜的研究

研究用连铸-挤压-冷拔的组合工艺生产一种含Bi的易切削黄铜棒，并用光学显微镜和X射线研究了该黄铜的显微组织，用拉伸试验机测定了该黄铜的抗拉强度和塑性。研究发现，该黄铜主要由α（Cu0.64Zn0.36）、β（CnZn）两相组成，Bi以单质的形式分布在晶界和相界上。冷拔使该黄铜强度增加（大于600MPa），塑性下降5％～9％。该黄铜完全可以取代现行的HPb59-1黄铜。     

从钨冶炼渣中综合回收有价金属的试验研究

某钨冶炼渣中含有较多的钨、锡、钼、铋等金属元素,具有综合回收和利用价值。但试样中WO3主要存在于+37μm粒级,Sn主要存在于37～76μm粒级,Bi主要存在于19～76μm粒级、Mo相对分散.。针对这一特征,采用先浮钼,然后调低pH值浮硫化矿,之后采用硫化浮选的方法浮选渣中的氧化铋,接着浮选白钨,最后重选回收锡的工艺,获得的铋、钨、锡精矿主金属的品位分别为:8.34%、17.51%、35.39%,对应主金属回收率分别为:72.62%、53.23%、65.94%,取得了较好的结果。     

Surface Segregation Mechanisms in Ferroelectric Thin Films

Reliability issues have hampered the adoption of ferroelectric thin films by the microelectronics industry. One of these is imprint, an important problem affecting the performance of ferroelectric non-volatile memories. This paper presents the effects of the low temperature pyrolysis step on the chemical and physical properties of SrBi₂Ta₂O₉ films. A comparison of the hysteretic properties and composition profiles shows that control of the oxidising conditions during pyrolysis is critical to the dielectric properties. Data from this work and from the literature have been used to construct a model that explains the origin of surface depletion and segregation, self poling and as-grown imprint in ferroelectric films.     

氧化铋的应用研究进展

氧化铋是一种先进的功能粉体材料,应用前景广阔.综述了氧化铋的国内外研究进展,详细介绍了氧化铋在电子陶瓷粉体材料、电解质材料、光电材料、高温超导材料、催化剂方面的应用,强调了其特殊性能的优势和应用潜力,阐明了我国研究开发氧化铋的意义.     

Construction of BiVO4 nanosheets@WO3 arrays heterojunction photoanodes by versatile phase transformation strategy

A versatile phase transformation strategy was proposed to synthesize novel BiVO₄ nanosheets (NSs)@WO₃ nanorod (NR) and nanoplate (NP) arrays films. The strategy was carried out by following a three-step hydrothermal process (WO₃→WO₃/Bi₂WO₆→WO₃/BiVO₄). According to the characterization results, plenty of BiVO₄ NSs grew well on the surface of WO₃ NR and NP arrays films, thus forming the WO₃/BiVO₄ heterojunction structure. The prepared WO₃/BiVO₄ heterojunction films were used as the photoanodes for the photoelectrochemical (PEC) water splitting. As indicated by the results, the photoanodes exhibited an excellent PEC activity. The photocurrent densities of the WO₃/BiVO₄ NR and NP photoanodes at 1.23 V (vs RHE) without cocatalyst under visible light illumination reached up to about 1.56 and 1.20 mA/cm^brespectively.     

Large Piezoelectricity and Ferroelectricity in Mn‐Doped (Bi0.5Na0.5)TiO3‐BaTiO3 Thin Film Prepared by Pulsed Laser Deposition

Mn‐doped (Bi_0.5Na_0.5)_0.94Ba_0.06TiO₃ (MnBNBT) thin films were prepared on SrRuO₃ (SRO)‐coated (001) SrTiO₃ (STO) single crystal substrates by pulsed laser deposition under different processing conditions. Structural characterization (i.e., XRD and TEM) confirms the epitaxial growth of STO/SRO/MnBNBT heterostructures. Through the judicious control of deposition temperature, the defect level within the films can be finely tuned. The MnBNBT thin film deposited at the optimized temperature exhibits superior ferroelectric and piezoelectric responses with remanent polarization P_r of 33.0 μC/cm² and piezoelectric coefficient d₃₃ of 120.0 ± 20 pm/V.