Ag3PO4体系光催化材料的研究进展:基础与改性（英文）

Ag3PO4是一种高效的光催化剂,因而受到了极大的关注。其高光催化活性归功于其内禀电子结构。采用形貌控制和纳米复合体构筑的方法提高其性能和实用性。综述Ag3PO4单晶的晶体结构、性能及其基础理论,并用一些典型例子来说明提高其光催化活性的主要策略,即形貌控制和纳米复合体的构筑。     

Ag/BiVO_4复合纳米纤维的制备及光催化性能

采用静电纺丝法制备了不同Ag负载含量的Ag/Bi VO_4纳米纤维复合材料,并对其相结构,形貌,可见光催化性能进行了表征。结果表明,Ag的引入能够很大程度提高复合材料的光催化效率,10%Ag负载的Ag/Bi VO_4复合纳米纤维能够在可见光辐照20 min内将罗丹明B完全降解。这种异质结够有利于光生电子空穴对的分离,提高光生载流子寿命,是Ag/Bi VO_4复合纳米纤维光催化性能显著提高的原因。     

Ag/BiVO4复合纳米纤维光催化性能的研究

本文采用静电纺丝法制备了不同Ag负载含量的Ag/BiVO₄纳米纤维复合材料,并对其相结构,形貌,可见光催化性能进行了表征。结果表明,Ag的引入能够很大程度的提高复合材料的光催化效率,10%Ag负载的Ag/BiVO₄复合纳米纤维能够在可见光辐照20min内将罗丹明B完全降解。这种异质结够有利于光生电子对的分离,提高光生载流子寿命,是Ag/BiVO₄复合纳米纤维光催化性能显著提高的原因。     

Ag包覆Ni复合纳米粉体的制备及其导电性能

用化学镀法,以葡萄糖为还原剂,制备了Ag包覆Ni复合纳米粉体,并用制备的复合纳米粉作为导电相配制了导电浆料。用XRD、TEM和电阻率测定等手段研究了粉体的相结构、形貌、粒度和导电性能。结果表明,制备的Ag包覆Ni复合纳米颗粒具有壳/核结构,核为纳米Ni,壳为Ag,复合纳米颗粒粒度分布为20~100 nm,Ag层的厚度约为4 nm。Ag包覆Ni复合纳米粉导电浆料在1.33 Pa的真空下,采用200℃/60 min的烧结工艺,可制得电阻率为(1.26~2.83)×10-4Ω·cm的导电膜,其导电性能优于纳米Ni粉、纳米Cu粉和纳米Ag-Cu合金粉导电浆料。     

铝合金表面微/纳米结构构筑研究进展

铝合金以其优异的性能而被广泛应用于工业生产的各个领域,通过一系列方法可以在铝合金表面构筑多种类型的微纳米结构。这些微纳米结构可以提高铝合金的摩擦学性能、耐蚀性能、界面结合力、抗结冰性以及装饰性能,对将铝合金应用到更广阔和更苛刻的环境中具有重要意义。介绍了铝合金表面微/纳结构的主要构筑方法。化学刻蚀法制备出了凸台和凹坑的迷宫形貌;阳极氧化法构筑出了高度有序的孔洞结构;微弧氧化法制备出了表面布满微孔的氧化膜;水热法可以构筑形状多样的纳米花朵形貌;电解加工对阴极材料的表面结构进行复刻,可以采用不同比例的阴阳极材料进行大面积的制备。阐述了这些微纳米结构的生长过程,并分析了实验条件(如温度、处理时间、电参数、溶液成分及浓度等因素)对铝合金表面微纳米二元结构生长的影响规律,重点总结分析了其研究现状和影响微纳米结构的因素。通过对现有铝合金表面结构制备方法的总结和分析,展望了其今后的发展趋势。     

铁的磷酸盐纳米颗粒的控制合成及表征

以FeCl3·6H2O、Na3 PO4和NaAc为原料,以乙二醇与水的混合物为溶剂,通过溶剂热法在210℃的条件下反应8h制备了铁的磷酸盐纳米颗粒.通过改变溶剂中乙二醇与水的量、Na3PO4的量、NaAc的量可以得到不同尺寸的铁的磷酸盐纳米颗粒样品.利用扫描电子显微镜(SEM)和X-射线粉末衍射(XRD)手段对产物的形貌和结构进行了表征和研究.     

纳米Cu_2O/Ag/TiO_2三层复合薄膜的结构及性能

通过磁控溅射方法制备了一种新颖的纳米Cu2O/Ag/Ti O2三层复合薄膜。用X射线衍射(XRD)仪、扫描电子显微镜(SEM)、紫外可见分光光谱仪(Uv-vis)和荧光光谱仪(FLO)对薄膜的晶体结构、表面形貌、光学性能及Ag金属中间层的存在对复合薄膜的影响进行了分析。此外,对薄膜光催化性能的研究表明,插入Ag层的纳米Cu2O/Ag/Ti O2三层复合薄膜显示出远高于Cu2O/Ti O2双层复合薄膜的可见光催化活性。催化性能的提高归因于Ag金属中间层的存在,提高了三层复合薄膜的可见光吸收强度,增加了表面积,促进了激发电子的转移及光生电子和空穴的分离。     

质粒DNA光化学反应制备Ag纳米颗粒

以碱基对数为7.5 kB的大肠杆菌环状质粒DNA为模板.通过紫外线辐射作用下的光化学反应方法制备了Ag纳米颗粒.采用紫外-可见光吸收光谱,TEM和EDS等方法研究了辐射时间、溶液浓度等工艺条件对Ag纳米颗粒组成、形貌和结构的影响.结果表明,获得的Ag纳米颗粒为fcc结构,颗粒直径为25—40 nm;一定条件下,Ag纳米颗粒为环状,中间孔洞直径为8—10 nm,Ag~+与碱基对数摩尔比为4、辐射时间为40 min时,Ag纳米颗粒中环状结构最多.     

铁酸钴纤维负载银/氯化银纳米粒子的合成及其对甲基橙的光催化降解（英文）

通过温和的湿化学合成法将Ag/AgCl纳米粒子固载于CoFe_2O_4纤维表面,固载银/氯化银纳米粒子的量可控。利用X射线衍射,扫描电子显微镜和电子显微镜等技术对制备的Ag/AgCl@CoFe_2O_4组成、形貌等进行了表征。以甲基橙的降解脱色为模型反应,考察了Ag/AgCl纳米粒子的不同负载量对催化性能的影响。实验结果表明:AAC-4型固载纤维光催化剂展示出比其它类型固载光催化剂以及单纯Ag/AgCl纳米粒子更高的光催化性能,可使甲基橙溶液60 min的脱色率达98.2%,且Ag/AgCl纳米粒子在CoFe_2O_4纤维表面的固载促进了光催化剂催化效率和催化稳定性的提升。     

固相-水热法制备LiFePO4-Li3V2（PO4）3复合材料及其电化学性能（英文）

分别采用固相-水热法和球磨法制备磷酸亚铁锂-磷酸钒锂复合正极材料(LiFePO4-Li3V2(PO4)3)。电化学性能测试表明,LiFePO4-Li3V2(PO4)3复合正极材料的电化学性能远远高于 LiFePO4和 Li3V2(PO4)3单独作为正极材料的性能,并且以固相-水热法制备的复合材料性能优于以球磨法制得的复合材料。研究发现 LiFePO4-Li3V2(PO4)3复合材料有 4 个氧化还原峰,相当于 LiFePO4 和 Li3V2(PO4)3 氧化还原峰的叠加。采用固相-水热法制备的LiFePO4-Li3V2(PO4)3 复合材料形貌较为规则,且有新相物质产生,这是导致其电化学性能较好的原因。     

Effects of Post-weld Heat Treatment on Microstructure,Mechanical Properties and the Role of Weld Reinforcement in 2219 Aluminum Alloy TIG-Welded Joints

In as-welded state, each region of 2219 aluminum alloy TIG-welded joint shows diff erent microstructure and microhardness due to the diff erent welding heat cycles and the resulting evolution of second phases. After the post-weld heat treatment, both the amount and the size of the eutectic structure or θ phases decreased. Correspondingly, both the Cu content in α-Al matrix and the microhardness increased to a similar level in each region of the joint, and the tensile strength of the entire joint was greatly improved. Post-weld heat treatment played the role of solid solution strengthening and aging strengthening. After the post-weld heat treatment, the weld performance became similar to other regions, but weld reinforcements lost their reinforcing eff ect on the weld and their existence was more of an adverse eff ect. The joint without weld reinforcements after the post-weld heat treatment had the optimal tensile properties, and the specimens randomly crack in the weld zone.     

The First Phase of the SRIF Industrialized Base in ＂West Area＂ Has Been Put into Operation

After nearly two years＇ tense construction, the first phase of industrialized base of Shenyang Research Institute of Foundry （SRIF）, located at the Tiexi Casting and Forging Industrial Park in the west of Tiexi District, has now been completed and formally put into operation.     

Thermodynamics Study on the Decomposition of Chromite with KOH

Institute of Process Engineering, Chinese Academy of Sciences, China, has proposed a method for oxidative leaching of chromite with potassium hydroxide. Understanding the mechanism of chromite decomposition, especially in the potassium hydroxide fusion, is important for the optimization of the operating parameters of the oxidative leaching process. A traditional thermodynamic method is proposed and the thermal decomposition and the reaction decomposition during the oxidative leaching of chromite with KOH and oxygen is discussed, which suggests that chromite is mainly destroyed by reactions with KOH and oxygen. Meanwhile, equilibrium of the main reactions of the above process was calculated at different temperatures and oxygen partial pressures. The stable zones of productions, namely, K2CrO4 and Fe2O3, increase with the decrease of temperature, which indicates that higher temperature is not beneficial to thermodynamic reactions. In addition, a comparison of the general alkali methods is carried out, and it is concluded that the KOH leaching process is thermodynamically superior to the conventional chromate production process.     

Influence of Heat Treatment on Damping Behaviour of the Magnesium Wrought Alloy AZ61

The effect of isochronal heat treatments for 1h on variation of damping, hardness and microstructural change of the magnesium wrought alloy AZ61 was investigated. Damping and hardness behaviour could be attributed to the evolution of precipitation process. The influence of precipitation on damping behaviour was explained in the framework of the dislocation string model of Granato and Lücke.     

Effect of Rare Earth Doping on Impedance,Modulus and Conductivity Properties of Multiferroic Composites:0.5(BiLa_xFe_(1-x)O_3)–0.5(PbTiO_3)

The Lanthanum-doped bismuth ferrite–lead titanate compositions of 0.5(Bi LaxFe1-xO3)–0.5(Pb Ti O3)(x = 0.05,0.10,0.15,0.20)(BLxF1-x-PT) were prepared by mixed oxide method.Structural characterization was performed by X-ray diffraction and shows a tetragonal structure at room temperature.The lattice parameter c/a ratio decreases with increasing of La(x = 0.05–0.20) concentration of the composites.The effect of charge carrier/ion hopping mechanism,conductivity,relaxation process and impedance parameters was studied using an impedance analyzer in a wide frequency range(102–106Hz) at different temperatures.The nature of Nyquist plot confirms the presence of bulk effects only,and non-Debye type of relaxation processes occurs in the composites.The electrical modulus exhibits an important role of the hopping mechanism in the electrical transport process of the materials.The ac conductivity and dc conductivity of the materials were studied,and the activation energy found to be 0.81,0.77,0.76 and 0.74 e V for all compositions of x = 0.05–0.20 at different temperatures(200–300 °C).     

Quantitative Analysis of the Crystallographic Orientation Relationship Between the Martensite and Austenite in Quenching–Partitioning–Tempering Steels

The orientation relationships(ORs)between the martensite and the retained austenite in low-and medium-carbon steels after quenching–partitioning–tempering process were studied in this work.The ORs in the studied steels are identified by selected-area electron diffraction(SAED)as either K–S or N–W ORs.Meanwhile,the ORs were also studied based on numerical fitting of electron backscatter diffraction data method suggested by Miyamoto.The simulated K–S and N–W ORs in the low-index directions generally do not well coincide with the experimental pole figure,which may be attributed to both the orientation spread from the ideal variant orientations and high symmetry of the low-index directions.However,the simulated results coincide well with experimental pole figures in the high-index directions{123}_(bcc).A modified method with simplicity based on Miyamoto’s work was proposed.The results indicate that the ORs determined by modified method are similar to those determined by Miyamoto’method,that is,the OR is near K–S OR for the low-carbon Q–P–T steel,and with the increase of carbon content,the OR is closer to N–W OR in medium-carbon Q–P–T steel.     

Using Finite Element and Contour Method to Evaluate Residual Stress in Thick Ti-6Al-4V Alloy Welded by Electron Beam Welding

This work was to reveal the residual stress profile in electron beam welded Ti-6Al-4V alloy plates(50 mm thick) by using finite element and contour measurement methods.A three-dimensional finite element model of 50-mmthick titanium component was proposed,in which a column–cone combined heat source model was used to simulate the temperature field and a thermo-elastic–plastic model to analyze residual stress in a weld joint based on ABAQUS software.Considering the uncertainty of welding simulation,the computation was calibrated by experimental data of contour measurement method.Both test and simulated results show that residual stresses on the surface and inside the weld zone are significantly different and present a narrow and large gradient feature in the weld joint.The peak tensile stress exceeds the yield strength of base materials inside weld,which are distinctly different from residual stress of the thin Ti-6Al-4V alloy plates presented in references before.     

Microstructures and Tensile Properties of Ultrafine-Grained Ni–(1–3.5) wt% SiC_(NP) Composites Prepared by a Powder Metallurgy Route

Silicon carbide nanoparticle-reinforced nickel-based composites(Ni–Si CNP),with a Si CNPcontent ranged from1 to 3.5 wt%,were prepared using mechanical alloying and spark plasma sintering.In addition,unreinforced pure nickel samples were also prepared for comparative purposes.To characterize the microstructural properties of both the unreinforced pure nickel and the Ni–Si CNPcomposites transmission electron microscopy(TEM) was used,while their mechanical behavior was investigated using the Vickers pyramid method for hardness measurements and a universal tensile testing machine for tensile tests.TEM results showed an array of dislocation lines decorated in the sintered pure nickel sample,whereas,for the Ni–Si CNPcomposites,the presence of nano-dispersed Si CNPand twinning crystals was observed.These homogeneously distributed Si CNPwere found located either within the matrix,between twins or on grain boundaries.For the Ni–Si CNPcomposites,coerced coarsening of the Si CNPassembly occurred with increasing Si CNPcontent.Furthermore,the grain sizes of the Ni–Si CNPcomposites were much finer than that of the unreinforced pure nickel,which was considered to be due to the composite ball milling process.In all cases,the Ni–Si CNPcomposites showed higher strengths and hardness values than the unreinforced pure nickel,likely due to a combination of dispersion strengthening(Orowan effects) and particle strengthening(Hall–Petch effects).For the Ni–Si CNPcomposites,the strength increased initially and then decreased as a function of Si CNPcontent,whereas their elongation percentages decreased linearly.Compared to all materials tested,the Ni–Si CNPcomposite containing 1.5% Si C was found more superior considering both their strength and plastic properties.     

Directional Growth of Tin Crystals Controlled by Combined Solute Concentration Gradient Field and Static Magnetic Field

A new method was introduced to achieve directional growth of Sn crystals. Microstructures in liquid(Pb)/liquid(Sn) diffusion couples were investigated under various static magnetic fields. Results show that the β-Sn crystals mainly reveal an irregular dendritic morphology without or with a relatively low static magnetic field(B0.3 T). When the magnetic field is increased to 0.5 T, the β-Sn dendrites close to the final stage of growth begin to show some directional character. With a further increase in the magnetic field to a higher level(0.8–5 T), the β-Sn dendrites have an enhanced directional growth character, but the dendrites show a certain deflection. As the magnetic field is increased to 12 T, the directional growth of the β-Sn dendrites in the center of the couple is severely destroyed. The mechanism of the directional growth of the β-Sn crystals and the deflection of the β-Sn crystals with the application of static magnetic field was tentatively discussed.     

Growth Kinetics of Single Inclusion Particle in Molten Melts

On the basis of the single-particle framework, a new theory on inclusion growth in metallurgical melts is developed to study the kinetics of inclusion growth on account of reaction and collision. The studies show that the early growth of inclusion depends on reaction growth and Brawnian motion collision, and where the former is decisive, the late growth depends on turbulence collision and Stokes＇ collision, and where the former is dominant; collision growth is very quick during the smelting process, lessened in the refining process, but nearly negligible in the continuous casting process.