ICP-AES测定纯金饰品中的痕量钯及其不确定度评估

建立了王水溶解纯金样品、标准基体匹配、电感耦合等离子体发射光谱(ICP-AES)测定纯金饰品中痕量钯元素的定量分析方法。该方法具有简便、快速、灵敏度高、重现性好等优点。方法检出限为0.08μg/g,加标回收率为104%,相对标准偏差(RSD)为7.52%,A类不确定度为0.0119 mg/L。     

阳离子交换ICP-OES测定高纯氧化铌中十三种杂质元素

样品用氢氟酸溶解,阳离子交换分离铌基体富集杂质元素,4mol/L硝酸洗脱杂质,用电感耦合等离子体发射光谱法测定。研究了阳离子交换的条件,考察了分离效率及残余铌量对测定的影响,绘制了洗脱曲线,相对0.2μg/g～5μg/g的加标回收率为82%～115%,相对标准偏差为0.31%～22.43%。     

电感耦合等离子体质谱法测定高纯氟钽酸钾中15种痕量杂质元素

使用硝酸及氢氟酸混合酸低温加热溶解样品,采用耐氢氟酸进样系统,应用屏蔽矩冷等离子体技术消除~(24)CC+、~(52)ArC+、~(56)ArO+等多原子离子对Mg、Cr、Fe等元素的干扰,以标准加入法定量,从而建立了电感耦合等离子体质谱法测定高纯氟钽酸钾中15种痕量杂质元素的分析方法。方法中各元素的检出限(3 s)在0.003 9μg/g～0.089μg/g之间。采用所建立的方法测定高纯氟钽酸钾中的15种痕量杂质元素,测定值的相对标准偏差(RSD,n=11)在1.08%～13.5%之间,加标回收率在91%～109%之间,可满足高纯氟钽酸钾中15种痕量杂质元素的分析要求,分析结果与电感耦合等离子体原子发射光谱法(ICP-AES)对照,结果相符。     

蒸发材料用高纯金的制备研究

采用盐酸+氯酸钠溶解-沉淀除杂-选择性液相还原-煮洗等联合工艺制备蒸发材料用高纯金并进行应用性能分析。结果表明,溶解后的金溶液采用氢氧化钠调整溶液pH值去除部分杂质元素;金溶液采用还原剂选择性还原;得到的金粉用稀硝酸、盐酸煮洗,获得纯度99.999%以上,碳和硫含量均小于1×10~(-6)的高纯金;以制备的高纯金为原料加工的蒸发材料清洁性好,可作为集成电路芯片制造用蒸发材料。     

汽车尾气净化催化剂中铂、钯和铑的测定

建立了电感耦合等离子体原子发射光谱法(ICP-AES)直接同时测定钛合金中合金元素或微量杂质硅钒铁铝镍钼铬的分析方法.采用氢氟酸和硝酸混合试剂并且在室温或70℃水浴控制加热条件下消解样品,从而避免了待测元素的挥发损失以及确保了高浓度钛基体在低酸度介质中也不会发生水解反应.试验了钛基体和共存元素对测定的光谱干扰影响,采取以钇作为内标元素的内标校正法,并且优选了待测元素分析谱线、内标校正谱线、同步背景校正位置以及ICP光谱仪工作条件,有效地消除基体钛导致的物理干扰以及改善方法精密度和检出限水平;方法实际应用结果表明:方法的检出限为10～27 μg/L,背景等效浓度5～38 μg/L,相关系数r≥0.9992;回收率95.0％～105.0％; RSD≤2.27％.     

废弃电路板中金的浸取研究

为回收电子废弃物中的贵金属金,先对废弃电路板进行破碎、焚烧得到灰渣,用原子吸收法对灰渣中的金等元素进行测定;然后用盐酸和硝酸对灰渣中的贱金属进行溶解,用盐酸和氯酸钠对金进行溶解;最后用X-射线光电能谱对粉末金进行分析。结果发现,电路板灰渣中金、铅、镉、铬的平均含量分别为0.097 2、5.164 9、0.003 9和0.099 7 mg/g;盐酸和氯酸钠浓度越高,金的提取率越高;当盐酸浓度和氯酸钠浓度分别为3.0 mol/L和12 g/L时,粉末金的提取率为71.40%;粉末金中含有大量纯金和少量主要为SiO_2的杂质。     

乙酸乙酯萃取-电感耦合等离子体原子发射光谱测定成品金锭中的痕量元素

通过研究并建立了在同一体系中经溶剂萃取后用电感耦合等离子体原子发射光谱测定成品金锭中31种杂质元素的方法。仪器检测限为0.0005~0.0798μg/m L,方法检测限为0.2~1.0μg/m L。改进后分析结果更加精确,提高了实验室分析水平,缩短了工作时间、减小劳动强度、减少污染。     

高纯金的电解工艺

介绍了遂昌金矿有限公司的高纯金电解工艺。实践表明,采用该工艺,在金阳极板含金95%~99%下经过一次金电解,金纯度即可达到99.997%以上。经检测,杂质含量低于高纯金(99.999%)的杂质要求。     

电感耦合等离子体质谱法测定高纯钨中26种痕量杂质元素

采用电感耦合等离子体质谱法(ICP-MS)测定高纯钨中26种痕量杂质元素,讨论了溶样方式,研究了质谱干扰和钨基体效应,应用屏蔽炬技术消除56Ar O+等多原子离子对Fe、Ca、K等元素的干扰,采用在线样品标准加入法消除基体效应。各元素的方法检出限(15σ)为0.03⁰.45μg/g,对样品加标0.5μg/g的回收率在88%0.45μg/g,对样品加标0.5μg/g的回收率在88%¹16%之间。方法适用于纯度为99.999%的高纯钨中痕量杂质元素的测定。     

TBP萃取剂从铜阳极泥盐酸-氯气浸出液中选择性萃取金（英文）

铜阳极泥的盐酸-氯气氧化性浸出会导致大量杂质元素如Fe、Cu、Pd、Se等的溶解。以TBP作为萃取剂,采用标准的溶剂萃取实验方法,等体积有机相和水相来萃取分离Au、Pd、Pt、Fe、Cu和Se等元素,研究TPB浓度、HCl和氯离子浓度对杂质分离效果的影响。结果表明,在有机相中TBP浓度为0.25 mol/L、水相中HCl浓度为2.5 mol/L的条件下,可以得到高的金萃取率。同时,其他杂质元素的萃取可以忽略不计。对负载有机相采用蒸馏水进行洗涤,可以去除部分杂质元素。采用硫代硫酸钠溶液进行反萃,反萃液中不含任何杂质元素。在反萃液中加入硫酸,反应产生的SO_2气体可还原金离子。     

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.     

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.     

Theoretical Analysis for the Motion and Temperature of Melt Droplets in Spray Degassing Process

The motion of melt droplets in spray degassing process was analyzed theoretically. The height of the treatment tank in spray degassing process could be determined by the results of theoretical calculation of motion of melt droplets. To know whether the melt droplets would solidify during spraying process, the balance temperature of melt droplets was also theoretically analyzed. Then proof experiments for theoretical results about temperature of melt droplets were carried. In comparison, the experimental results were nearly similar to the calculation results.     

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.