中国钽铌湿法合金

介绍了中国钽铌湿法冶金发展概况与现状及中国钽铌湿法冶金主要感受家和所用工艺流程特点,不叙述了各厂家在产品质量,工艺,设备等方面所取得的技术进步,燕指出今后工作的主要方向,目的在于进一步提高产品质量及利用低品位矿石原料处理回收废水废气,降低物料消耗,改进环境保护。     

钽铌工业生产及其展望

简述了钽、铌工业生产的新进展，重点介绍了钽、铌矿和钽、铌产品的生产技术进步和应用现状；分析了钽、铌产品的市场结构和价格走势，最后展望了钽、铌工业生产的未来发展。     

2007年钽铌工业发展评述

评述了2007年中国钽铌工业的运行状况。在世界钽铌产品总需求持续增长的带动下,中国钽铌工业继续保持良好的增长势头,工业生产总值达到22．79亿元,销售收入达到23．37亿元,分别比上年增长了27．9％和28．8％。2007年是中国钽铌工业快速发展的一年,矿产量和冶炼品产量增加,高端钽铌产品的加工和出口快速增长。最后分析了中国钽铌工业发展中存在的突出问题,并提出了促进行业发展的措施。     

让世界感受“东方”的力量--宁夏东方有色金属集团有限公司

宁夏东方有色金属集团有限公司是主要从事稀有金属钽、铌、铍等高科技产品的研究、开发和生产的出口外向型企业,是国内最大的钽铌生产厂家和科技先导型的钽铌铍研究单位,是国内惟一的铍材加工基地,是国际钽铌研究中心(TIC)中国成员单位,是世界钽冶炼加工三强企业之一,是自治区     

中国钽铌湿法冶金

介绍了中国钽铌湿法冶金发展概况与现状及中国钽铌湿法冶金主要厂家和所用工艺流程特点,还叙述了各厂家在产品质量、工艺、设备等方面所取得的技术进步,并指出今后工作的主要方向,目的在于进一步提高产品质量及利用低品位矿石原料处理回收废水废气,降低物料消耗,改进环境保护。     

2006年中国钽铌工业发展述评

评述了2006年中国钽铌工业的运行状况。在世界钽铌产品总需求持续增长的带动下，中国钽铌工业也呈现出良好的增长势头，总产值达到17．82亿元，销售收入达到18．15亿元，与2005年相比分别增长了23．58％和20％。中国电容器用钽粉和钽丝的质量已接近国际先进水平，产量已分别占世界产量的21％和56％以上，出口总量达到总产量的90％以上。最后分析了中国钽铌工业发展中存在的突出问题，并提出了促进行业发展的措施。     

第7次全国钽铌冶金学术年会及2004年钽铌联合体会议在春城昆明召开

由钽铌专业学术委员会和钽铌联合体共同主办的第7次全国钽铌冶金学术年会及2004年钽铌联合体会议于11月21日～22日在春城昆明举行。来自全国38家企事业单位的74名代表出席了本次会议。     

10万吨电解锌项目在会理有色产业园奠基

8月9日,中国有色金属工业协会钽铌分会成立大会在京举行。会议宣布了中国有色金属工业协会关于成立钽铌分会的批复,中国有色金属工业协会会长康义为钽铌分会授牌。     

钽铌电子材料新进展(Ⅰ)

代表中国钽铌工业整体水平的宁夏东方有色金属集团有限公司,近年来,研究了钽粉的微观结构,开发出降低杂质含量,改善物理性能等新技术以及Ta2O5钠还原制取高比容钽粉、TaCl5低温钠还原制取纳米级钽粉的新工艺方法;研制并生产出性能优良的、适用于钽电容器的高比容钽粉,同时也开发了高比容铌粉、一氧化铌粉的制造新技术,制得高性能的电容器级铌粉和一氧化铌粉,为铌电容器作为一种新型电容器产业参与竞争提供了优质的基础材料。     

钽铌电子材料新进展(Ⅱ)

代表中国钽铌工业整体水平的宁夏东方有色金属集团有限公司,近年来,研究了钽粉的微观结构,开发出降低杂质含量、改善物理性能等新技术以及钠还原Ta2O5制取高比容钽粉、低温钠TaCl5还原制取纳米级钽粉的新工艺方法;研制并生产出性能优良的、适用于钽电容器的高比容钽粉,同时也开发了高比容铌粉、一氧化铌粉的制造新技术,制得高性能的电容器级铌粉和一氧化铌粉,为铌电容器作为一种新型电容器产业参与竞争提供了优质的基础材料。     

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.     

电化学噪声数据处理方法概述

综述了常见的电化学噪声数据处理方法,介绍了直流趋势剔除、统计分析、快速傅立叶变换(FFT)法计算功率谱密度(PSD)以及小波变换处理电化学噪声信号的基本过程,并阐释了各种数学处理及所得参数的物理意义。