Microstructure, morphology and electrochemical property of RuO270SnO230 mol% and RuO230SnO270 mol% coatings

The DSA anodes based on RuO₂–SnO₂ oxides are most employed in chlorine-alkali cells. Their properties are strongly influenced by the mixed-oxide coating structures. In this paper, two RuO₂–SnO₂/Ti DSA anodes with different Ru and Sn molar ratios were prepared through a sol–gel technique. The nano-structure, morphology, grain structure and composition of the coatings were investigated by means of XRD, SEM and TEM. XRD analysis indicates two rutile-type solid solutions are formed. Peak profile analysis shows that in the solid solution where SnO₂ is the major component smaller crystallites (about 20–30 nm) are formed than in those where RuO₂ is the major component (about 100–200 nm). The SEM images reveal the coating with high level of SnO₂ possesses more accumulated and compact structures. The EDS analysis indicates that two DSA anodes coatings in which SnO₂ is similar to the designed concentration are prepared by the sol–gel method. TEM characterization shows the polygonal crystallites are present in the obtained RuO₂–SnO₂ coatings. The voltages of Cl₂-evolution and O₂-evolution suggest both RuO₂–SnO₂/Ti DSA anodes have a good electrochemical performance and can be used for the chlorite industrial productions.     

Mg-substituted ZnNb2O6-TiO2 composite ceramics for RF/microwaves ceramic capacitors

Microstructure and microwave dielectric properties of Mg-substituted ZnNb₂O₆-TiO₂ microwave ceramics were investigated. Mg acted as a grain refining reagent and columbite phase stabilization reagent. With an increasing Mg content, the amount of ixiolite (Zn, Mg) TiNb₂O₈ decreased, and the amount of (Zn_0.9Mg_0.1)_0.17Nb_0.33Ti_0.5O₂ and columbite increased. ZnO-Nb₂O₅-1.75TiO₂-5 mol.%MgO exhibited excellent dielectric properties (at 950 °C): ?_r = 35.6, Q × f = 16,000 GHz (at 5.6 GHz) and τ_f = −10 ppm/°C. The material was applied successfully to make RF/microwaves ceramic capacitor, whose self-resonance frequency was 19 GHz at low capacitance of 0.13 pF.     

Synthesis and characterization of well-aligned catalyst-free phosphorus-doped ZnO nanowires

Highly crystalline P-doped ZnO nanowires were grown by physical vapour transport technique without presence of any catalysts. Grown nanowires were well aligned and had good crystallinity with evolution of preferred orientation (0 0 2). Both EDX and Rutherford backscattering spectrometry (RBS) results revealed that phosphorus atoms were incorporated in the ZnO nanowires with the content of less than 1%. The XRD results confirmed an increase in lattice spacing which is attributed to substitution of P on oxygen sites. The photoluminescence spectra of grown nanowires showed a strong emission peak at 3.248 eV with a shoulder at 3.184 eV, corresponding with FA (free electron to acceptor) and DAP (donor-acceptor pair) levels of P-doped ZnO. The lattice spacing from HRTEM agrees with the achieved results from XRD measurement.     

Preparation and characterization of nano TiO2/micron Cr2O3 composite particles

Nano-TiO₂/micro-size Cr₂O₃ composite particles were first prepared by hydrolysis of Ti(OBu)₄ in an abundant acidic aqueous solution without calcinations at room temperature. XPS analysis shows that the element C, O, Ti and Sn existed on the surfaces of the composite particles. Observation by field emission scanning electronic microscope shows TiO₂ particles of 10-15 nm covers on Cr₂O₃ powder surfaces to form nanometer/micron composite particles. UV-vis spectra show a red shift of the absorption edge and a significant increase of absorption intensity in the visible region. These results confirm that TiO₂ of anatase type can be synthesized on the surface of Cr₂O₃.     

SnO2@TiO2核-壳纳米线的制备及其光催化性能研究

本文通过固-液-气(VLS)生长机制,利用化学气相沉积法(CVD)制备SnO₂纳米线。利用原子层沉积(ALD)以钛酸四异丙酯为前驱体在SnO₂纳米线表面沉积不同厚度的TiO₂壳层,形成SnO₂@TiO₂核-壳纳米线结构。通过中间Al₂O₃插层,分别制备出金红石和锐钛矿两种不同晶型的TiO₂,从而制备出两种不同复合结构的SnO₂@TiO₂核-壳纳米线。实验研究该复合结构中TiO₂的厚度与晶型对紫外光下光催化降解甲基橙溶液活性的影响。     

A novel method to synthesize anatase TiO2 nanowires as an anode material for lithium-ion batteries

We demonstrate a simple and novel approach for the synthesis of a kind of anatase TiO₂ nanowires. The method is based on a hydrothermal method under normal atmosphere without using the complex Teflon-lined autoclave, high concentrations NaOH solution and long react time. The as-prepared materials are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and electrochemical measurements. The obtained anatase TiO₂ nanowires show excellent performance. There is a potential plateau at 1.77 and 1.88 V in the process of Li insertion and extraction, and the initial Li insertion/extraction capacities are 283 and 236 mAh g⁻¹ at the density of 20 mA g⁻¹, respectively. In the 20th cycle, the reversible capacities still remain about 216 and 159 mAh g⁻¹ at the current densities of 20 and 200 mA g⁻¹, respectively, and the coulombic efficiency is more than 98%, exhibiting excellent electrochemical performance.     

Critical behavior and the absence of glass state in ferromagnetic La0.7Ca0.3CoO3 nanowires

We report a systematic study of the magnetic and thermodynamic properties of uniform La_0.7Ca_0.3CoO₃ nanowires prepared by a hydrothermal method, and compare them with the bulk counterpart. The nanowires, ∼59 nm in diameter, are single crystalline as revealed by electron microscopy. With decreasing temperature, the bulk La_0.7Ca_0.3CoO₃ shows a ferromagnetism followed by a reentrant glass state, whereas the nanowires show only a purely ferromagnetic ground state. The thermopower and specific heat results indicate that there exist enhanced spin and/or orbital fluctuations in the nanowires that could be responsible for the absence of the glass state. Critical behavior analysis shows that the nanowires fall into a three-dimensional Heisenberg ferromagnet class.     

Cu2O/TiO2/Pt复合薄膜的制备及其性能

为了降解环境污染物,通过磁控溅射的方法在玻璃基底上溅射沉积Cu2O/TiO2/Pt复合薄膜。采用X射线衍射仪(XRD)、扫描电子显微镜(SEM)、紫外可见分光光谱仪(UV-vis)和光致发光光谱仪(PL)对复合薄膜的表面形貌和光学性能进行分析。通过可见光下对甲基橙溶液的光催化降解试验研究了薄膜的光催化活性。结果表明:Cu2O/TiO2/Pt复合薄膜共有3层,从下到上依次为Pt层、锐钛矿型TiO2层和Cu2O层。薄膜表面平整致密,由形状规则的球形颗粒组成。Cu2O/TiO2/Pt复合薄膜的光催化活性高于Cu2O/TiO2复合薄膜的和纯TiO2薄膜的光催化活性。光催化活性的提高是由于Pt层的存在进一步抑制了光生电子与空穴的复合,延长了光生载流子的寿命,提高了量子产率,进而有效地改善了薄膜的光催化活性。     

Structure and electrochemical performance of FeF3/V2O5 composite cathode material for lithium-ion battery

Orthorhombic structure FeF₃ was synthesized by a liquid-phase method using FeCl₃, NaOH and HF solution as starting materials, and the FeF₃/V₂O₅ composites were prepared by milling the mixture of as-prepared FeF₃ and the conductive V₂O₅ powder. The properties of FeF₃/V₂O₅ composites were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), galvanostatic charge/discharge and cyclic voltammetry measurements. Results showed that the FeF₃/V₂O₅ composites can be used as cathode material for lithium-ion battery. Electrochemical measurements in a voltage range of 2.0–4.5 V reveal that the addition of conductive V₂O₅ improves significantly the electrochemical performance of FeF₃, and the FeF₃/V₂O₅ composite prepared by milling for 3 h exhibits high discharge capacity and good cycle performance, and its discharge capacity maintains about 209 mAh g⁻¹ at 0.1 C (23.7 mA g⁻¹) after 30 cycles.     

Preparation of Fe2O3/graphene composite and its electrochemical performance as an anode material for lithium ion batteries

The micro-sized sphere Fe₂O₃ particles doped with graphene nanosheets were prepared by a facile hydrothermal method. The obtained Fe₂O₃/graphene composite as the anode material for lithium ion batteries showed a high discharge capacity of 660 mAh g⁻¹ during up to 100 cycles at the current density of 160 mA g⁻¹ and good rate capability. The excellent electrochemical performance of the composite can be attributed to that graphene served as dispersing medium to prevent Fe₂O₃ microparticles from agglomeration and provide an excellent electronic conduction pathway.     

氧化亚铜纳米颗粒的制备及其释放速率测定

针对涂料中氧化亚铜纳米颗粒作为防污剂在海水中存在释放速率不稳定的问题,采用化学还原法,通过控制溶液中葡萄糖的浓度和pH值制备出具有不同形状和粒径的氧化亚铜纳米颗粒,利用扫描电子显微镜(SEM)、X射线衍射仪(XRD)以及动态光散射粒度分析仪(DLS)表征所合成的氧化亚铜纳米颗粒的形状、粒径以及物相,利用电感耦合等离子体发射光谱仪(ICP)考察多种形状和粒径的氧化亚铜纳米颗粒在人工海水中的释放速率。结果表明:对于形状而言,球形释放速率最快,其次为正八面体,立方形释放速率最慢;在同一形状下,粒径越小释放速率越快,其中球形粒径在398.5nm的释放速率最快,立方形粒径在801.5nm的氧化亚铜释放速率最慢。     

Preparation and characterization of hydroxyapatite/titania composite coating on NiTi alloy by electrochemical deposition

NiTi alloy is used as biomaterial due to its unique properties, but the high content of Ni (about 50 at.%) in biomedical NiTi is of concern. Hydroxyapatite/titania composite coating was directly electrodeposited on the surface of NiTi alloy. The coated samples were characterized using X-ray diffraction, scanning electron microscopy, infrared spectroscopy, bonding strength test, polarization and electrochemical impedance spectroscopy (EIS). Results showed that addition of TiO₂ to the electrolyte changed the morphology of hydroxyapatite from thin flake-flower-like crystals to needle-flower-like crystals, and the coating was much denser. Besides, hydroxyapatite crystal grains in the coating were preferentially arranged in the [001] direction, which was perpendicular to the surface of NiTi alloy. The addition of TiO₂ improved the bonding strength between the coating and the substrate. Corrosion resistance of NiTi in the simulated body fluid at 37 °C was significantly improved by more than 50 times by electrodeposition of the hydroxyapatite/titania composite coating.     

Preparation and characterization of TiO_2/acrylic resin composite coatings on sintered NdFeB permanent magnets by electrochemical deposition

The sintered Nd Fe B permanent magnets are widely used in various industries because of their excellent magnetic and comprehensive properties. However, they are seriously hindered to further developments and applications owing to its poor corrosion resistance. In this paper,TiO2/acrylic resin composite coatings were successfully prepared on the sintered Nd Fe B permanent magnets by electrochemical deposition for the first time, and the corrosion behaviors were investigated by using immersion testing and potentiodynamic polarization tests. It is found that the coating is a composite, being composed of polymerized acrylic resin as the matrix and nano-rutile TiO2particles(-200 nm) as the reinforcements. It is about25 lm in thickness and its surface and cross-section exhibit uniform and smooth with no pores, cracks, and other defects. Compared with those of the uncoated Nd Fe B magnets, the weight loss of the coated samples immersed in H2SO4 solution reduces by two orders of magnitude,corrosion current density decreases by four orders of magnitude, and the corrosion potential of the coated sample is shifted in the noble direction by 400 m V. The mechanisms of corrosive resistance enhancement were discussed.     

空心聚吡咯/V_2O_5复合材料的制备及其电化学性能

为改善晶态V2O5（c-V2O5）正极材料实际容量较低、循环性能较差等问题,制备了空心球聚吡咯/V2O5复合材料。利用导电吡咯单体（Py）在中空型V2O5层间发生原位氧化聚合反应制备聚吡咯（PPy）/中空型V2O5复合材料（HS-PPy/V2O5）。采用X射线衍射仪（XRD）、扫描电镜（SEM）、透射电镜（TEM）对样品进行表征,采用恒流充放电测试和电化学阻抗（EIS）测试样品的电化学性能。结果表明,Py单体已插入中空型V2O5层间,与纯中空型V2O5相比,制备的HS-PPY/V2O5复合材料比容量虽然有所减小,但是循环稳定性有较大的提高。     

Preparation and characterization of plasma sprayed Ni3Al-hBN composite coating

Ni₃Al-hBN composite powders were manufactured by spray drying technology, and then plasma sprayed to form the coatings. The influence of hBN addition amount on the flowability and apparent density of the composite powders, as well as the mechanical and tribological properties of the as-sprayed coatings was evaluated. The results indicate that the spherical powders with uniformly distributed compositions are successfully manufactured by spray drying technology. Both the flowability and apparent density of the Ni₃Al-hBN powders, as well as the bond strength and hardness of the composite coatings decrease with the increase of hBN content. Addition of hBN less than 10 wt.% reduces the friction coefficient and brittle fracture of the coatings, which is beneficial to improve the tribological properties of the Ni₃Al-hBN composite coatings. However, high hBN addition, damaging the bond in the coating, will deteriorate the wear resistance of the coating. The Ni₃Al-hBN composite coating containing 10%hBN shows the optimum properties combining strength and hardness with tribological properties.     

SNDC/La2Mo2O9复合电解质材料的制备及性能表征

本文采用甘氨酸-硝酸盐法(GNP)和溶胶凝胶法分别合成了Sm_0.1Nd_0.1Ce_0.8O_1.9(SNDC) 和La₂Mo₂O₉(LAMOX)粉末,并用常压烧结的方法制备了不同比例的SNDC和LAMOX的复合材料,通过XRD和SEM等手段表征了不同复合比例样品的物相和表面形貌并测试了烧结样品的电导率。结果表明,复合样品的电导率在相变点前后随着复合量增加变化趋势相反,其中LAMOX含量为20mol%的样品在550℃时的电导率能达到0.01S/cm,高于同温度下SNDC电导率。     

Zn0.95Co0.05O纳米线和纳米管的电泳沉积法可控合成（英文）

以阳极氧化铝为模板通过电泳沉积法制备Zn0.95Co0.05O纳米线和纳米管,并对电泳沉积法制备纳米线(管)的机理进行研究。系统的结构表征表明所得的纳米管和纳米线是由8～15nm的纤锌矿纳米晶构成的多晶结构,Co2+离子以代位掺杂形式掺入晶格,取代了晶格中的Zn2+离子。磁性表征显示制备的纳米线和纳米管具有室温铁磁性。由于Co在纳米线(管)中表面择优分布,纳米管的磁性明显高于纳米线。     

The experimental determination of potential-pH diagrams for the Ni-H2O and low alloy steel-H2O systems

Potential-pH diagrams for the Ni-H₂O and two turbine disc steel-H₂O systems were determined experimentally. This was done in an attempt to gauge the protective action of a nickel electrodeposit on a turbine disc substrate. XPS analyses of various critical regions found on the diagrams were carried out in order to characterize the nature of the films formed under various conditions of potential and pH.     

SnO2/Ni复合锂离子电池负极材料的制备及其电化学性能

采用机械球磨法将纳米SnO2和Ni粉末复合,作为锂离子电池负极材料。采用XRD、SEM、TEM和EDS分析球磨过程中材料结构和形貌的变化。对SnO2/Ni复合负极材料的首次库仑效率、循环稳定性及CV曲线等进行测试分析。结果表明:将复合粉末球磨适当时间后,SnO2和Ni可形成结合充分、颗粒尺寸细小、分布均匀的复合材料;SnO2和Ni的复合可有效提高SnO2的首次库仑效率和循环稳定性;SnO2/Ni复合负极材料的循环稳定性随球磨时间的延长而增加,但电极的首次库仑效率随球磨时间的延长呈先增加后下降的趋势;Ni的引入有效减小了SnO2在首次充放电循环过程中生成Li2O的不可逆反应程度,并在随后的循环过程中部分以Li-O化合物的形式进行可逆反应。     

新型复合贮氢合金Zr0.9Ti0.1（Ni,Co,Mn,V）2.1的制备与电化学性能

采用熔铸方法制备母合金Zr0.9Ti0.1(Ni,Co,Mn,V)2.1,进而在母合金基础上添加吸氢剂B,利用球磨制得4种复合贮氢合金,X射线衍射结果表明,随着球磨时间的增加,复合合金由晶态转化为非晶态;电化学测试结果表明,复合合金经过1-2次球磨就能完全活化,具有很好的活化性能;在60mA/g电流下,复合贮氢合金C和D的稳定容量均可达到440mA.h/g左右,比母复金高出80mA.h/g;但随着球磨时间的延长,所得的复合金容量比铸态母合金的还低;在300mA/g电流下,复合合金D具有较好的循环稳定性,经过200次循环后其容量仅衰减3%。