含H2S的强酸性溶液中Cl^—对铁腐蚀的影响

应用化学动电位扫描和交流阻抗法研究了Ｈ２Ｓ的Ｈ２ＳＯ４溶液中Ｃｌ＾－对腐蚀的影响。结果表明，在含Ｈ２Ｓ的０．５ｍｏｌ／ＬＨ２ＳＯ４溶液中，Ｃｌ＾－１能同时抑制铁腐蚀的阴，阳极反应，且Ｃｌ＾－的抑制作用存在浓度极值现象，极值点为１ｍｏｏ／Ｌ；     

哌啶缓蚀作用的原子吸收光谱研究I.304不锈钢,工业纯铁 …

采用原子吸收光谱（ＡＡＳ），恒电位下电流～时间关系和极化曲线测试等方法研究了３０４不锈钢，纯铁，铬和镍四种材料在０．１ｍｏｌ／ＬＨＣｌ中的腐蚀行为及哌啶（ＰＤ）的缓蚀作用，结果表明：ＰＤ可有效地抑制３０４不锈钢在盐酸中的腐蚀，ＰＤ增强Ｃｒ在盐酸中的钝化性能，对铁，镍的腐蚀属阴极型缓蚀剂，在ＡＡＳ测试结果表明，３０４不锈钢的组分元素Ｆｅ，Ｃｒ，Ｎｉ和Ｍｎ在盐酸中分别为＋２，＋３，＋２和＋２价离子问式     

改性咪唑啉缓蚀剂在H2S-3%NaCl-H2O体系中缓蚀性能的研究

以环烷酸和二乙烯三胺为原料，合成了咪唑啉，分别经过了乙氧基化反应和季铵化反应对其改性得到ＨＭ、ＨＭＯ，并在Ｈ２Ｓ－３％ＮａＣｌ－Ｈ２Ｏ体系中通过腐蚀实验及极化曲线测量，对其缓蚀性能进行了评价，实验结果表明，ＨＭ、ＨＭＯ对抑制Ｈ２Ｓ－３％ＮａＣｌ－Ｈ２Ｏ体系中碳钢的腐蚀有良好的效果，二者均有以控制阳极反应为主的混合型缓蚀剂。     

NaCl浓度对 API P105钢在CO2溶液中的电化学腐蚀行为影响

用极化曲线和电化学阻抗谱（ＥＩＳ）研究了含ＣＯ２溶液中,ＮａＣｌ含量对ＡＰＩ Ｐ１０５钢的电化学性能影响,结果表明：ＮａＣｌ含量的增大,抑制了阴阳极反应,降低了钢铁的腐蚀速度,提高了腐蚀电位,同时Ｃｌ＾－在ＡＰＩ Ｐ１０５钢表面的吸附为Ｔｅｍｋｉｎ等温吸附。     

Ni—18Cr—3.5Al合金在Cl2—H2O环境中的高温腐蚀

研究了Ｎｉ－１８Ｃｒ－３．５Ａｌ合金在５６５℃Ｃｌ２－Ｈ２Ｏ混合气氛中的腐蚀行为，并用ＸＰＳ分析了腐蚀产物膜的结构。在高温Ｃｌ２－Ｈ２Ｏ环境中的腐蚀由Ｃｌ２、ＨＣｌ造成的氯化过程和Ｏ２、Ｈ２Ｏ等造成的氧化过程共同引起。在高温Ｃｌ２环境中低含量Ｈ２Ｏ加速腐蚀过程，而高含量Ｈ２Ｏ延缓腐蚀过程。     

Ni－18Cr－3．5Al合金在Cl_2－H_2O环境中的高温腐蚀

研究了Ｎｉ－１８Ｃｒ－３．５Ａｌ合金在５６５℃Ｃｌ２－Ｈ２Ｏ混合气氛中的腐蚀行为，并用ＸＰＳ分析了腐蚀产物膜的结构。在高温Ｃｌ２－Ｈ２Ｏ环境中的腐蚀由Ｃｌ２、ＨＣｌ造成的氯化过程和Ｏ２、Ｈ２Ｏ等造成的氧化过程共同引起。在高温Ｃｌ２环境中低含量Ｈ２Ｏ加速腐蚀过程，而高含量Ｈ２Ｏ延缓腐蚀过程。     

模拟油田水介质中P110钢的CO2腐蚀机理

利用ＥＩＳ等技术研究了常温常压下Ｐ１１０油管钢在模拟油田采出液中受ＣＯ２腐蚀的电化学行为,结果表明,附加的阻极反应－Ｈ２ＣＯ２的直接还原,是导致ＣＯ２条件下的活性溶解腐蚀比相同ＰＨ的强酸慢更为严重的主要原因;模拟介质中的阳性极活溶解过程遵循“ＰＨ依赖机理”阴极反应则包括Ｈ＾＋的还原,Ｈ２ＣＯ２的还原,ＨＣＯ＾０３的还原和Ｈ２Ｏ的还原。     

H2S水溶液中的腐蚀与缓蚀作用机理的研究：Ⅲ.不同pH值 …

利用极化曲线和阻抗技术,对低碳钢在不同ＰＨ值Ｈ２Ｓ溶液中的腐蚀电化学行为进行了研究。结果表明,在溶液ＰＨ值较低时,腐蚀电极极酸性溶解过程控制,表面无硫化物沉积,其阻抗谱除高频容机弧外,低频有一感抗弧存在;随ＰＨ的升高,腐蚀电位明显负移,电流密度减小,表面出现硫化物的不连续沉积,腐蚀因溶液Ｐ珠增另和硫化物的沉积而减小,电极过程主要受硫化物的生长所控制;在ＰＨ值６．２时,由于ＨＳ的阴极去极化,腐蚀电流     

铁在含H2S在撤酸溶液中的腐蚀机制研究

应用动电位极化曲线和交流阻方法，研究了铁在含Ｈ２Ｓ的硫酸溶液中的腐蚀电化学行为，得出阴，阳极反应的动力学方程，并结合ＣＮＤＯ／２量化计算结果，提出了相应的腐蚀反应机制。结果表明，Ｈ２Ｓ可大大促进铁阳极溶解反应，且低极化时反应较快，相应动力不参数为：ｖＨ＋＝－０．８３，ｖＨＳ－＝０．３５，ｂａ≈４０ｍＶ；Ｈ２Ｓ对阴极反应的促进程度较小，且不随Ｈ２Ｓ浓度改变，相应动力学参数为：ｖＨ＋＝１．１９，ｖＨ２     

H2S水溶液中的腐蚀与缓蚀作用机理的研究：Ⅰ.酸性H2S溶液 …

利用交流阻抗（ＥＬＳ）和极有化曲线结合扫描电镜（ＳＥＭ）和能谱分析,对常温下低碳钢在含Ｈ２Ｓ的模拟炼厂常减压塔横张水中的腐蚀电化学行为和不同浸泡时间下硫化物膜的生长过程进行了研究。结果表明,Ｈ２Ｓ对腐蚀反应的阴极过程有很大的促进作用,搅拌条件下尤甚;随介质ＰＨ值升高,其腐蚀性减弱。腐蚀浸泡初期（小于８ｈ）,电极表面硫化物膜的生长尊循抛物线机制,随浸泡时间的延长,硫化物膜变得疏松、易于破裂和脱落,并     

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).     

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.     

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.     

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。