海洋工程钢结构阴极保护新型阳极的研究

海洋工程钢结构阴极保护设计阳极重量要同时满足物料概算和初始电流密度的需求。为达到保护要求,两者需取其大值,从而造成阳极用量过大的浪费。而通过使用新型阳极,可以提高阳极表面积与体积比值,即发生电流与阳极质量的比值,减少阳极材料的浪费。通过室内模拟阴极保护试验测量系统,对常规构型阳极(长条型)与新型阳极(翼型)的阴极保护效果进行对照比较,从而确认新型阳极的电化学性能及实际可行性。结果表明,若以新型阳极替代常规方条型阳极,便可在满足初期阳极发生电流需求情况下大大减少阳极重量,从而避免阳极的浪费。     

循环伏安法对新型阳极的电化学性能研究

通过对成分相同、电化学性能相同、重量相同、长度相同的常规方条型阳极与长直翼型阳极循环伏安对比实验,研究计算和分析评价两者的阳极(积分)极化面电阻率与阳极(积分)极化面电阻,确定新型阳极的发生电流与其构型及表面积增加的相关性,以及对复合阳极的循环伏安测试,研究铝-镁复合阳极的电化学性能。     

新型铝合金阳极的退火处理工艺

制备了两种不同含量的Al-Ga-In-Zn-Mg-Mn新型铝合金阳极材料,研究了退火处理对该合金在碱性溶液中自腐蚀速率和电化学性能的影响。结果表明：合金元素的均匀分布可降低铝阳极的自腐蚀速率,不同的退火处理制度对合金的自腐蚀速率影响极大。高温退火处理能在一定程度上改变合金元素的存在形式,减少或消除合金元素在晶界的富集或第二相质点,能极大地降低阳极材料的腐蚀速率；但对铝阳极电化学性能影响甚微。研制出的新型铝合金阳极材料具有优良的电化学性能和良好的耐腐蚀性能。     

新型铅钙板栅合金阳极腐蚀膜的性能研究

利用阳极极化曲线和交流阻抗技术研究了新型板栅合金与传统合金的耐腐蚀性能.应用现代表面技术XPS和XRD研究了合金在0.9 V下腐蚀6h所形成的阳极腐蚀膜的组成.结果表明,新型铅钙合金的耐腐蚀性能优于传统合金,其阳极腐蚀膜中导电性差的二价铅含量减少,四氧化铅的含量增大,其阳极腐蚀膜的电阻减少;新型铅钙合金可以明显改善铅酸电池的深循环性能,可以作为新一代免维护铅酸电池的板栅材料.     

新型铝合金阳极的退火处理工艺

制备了两种不同含量的Al-Ga-In-Zn-Mg-Mn新型铝合金阳极材料．研究了退火处理对该合金在碱性溶液中自腐蚀速率和电化学性能的影响。结果表明：合金元素的均匀分布可降低铝阳极的自腐蚀速率．不同的退火处理制度对合金的自腐蚀速率影响极大。高温退火处理能在一定程度上改变合金元素的存在形式，减少或消除合金元素在晶界的富集或第二相质点，能极大地降低阳极材料的腐蚀速率；但对铝阳极电化学性能影响甚微。研制出的新型铝合金阳极材料具有优良的电化学性能和良好的耐腐蚀性能。     

阴极保护中阳极材料发展最新动态及趋势

阳极材料包括牺牲阳极材料和辅助阳极材料二大类。随着阴极保护技术在我国国民经济中的广泛应用,短短30年间,阳极材料获得了快速的发展。本文全面系统地总结了阳极材料的种类性能,同时介绍了新发展起来的现代新型阳极材料,分析了现代阳极产品的优势和不足,初步预测了阳极材料未来的发展趋势。     

海水电池用镁阳极的研究与应用

镁阳极材料具有电负性好,比能量高以及密度小等优异性能,在海水电池领域具有广阔的应用前景。综述了近年来国内外镁阳极海水电池的研究及应用,讨论镁阳极材料的活化机制和腐蚀行为,探讨合金元素和第二相对镁阳极电化学活性和耐腐蚀性能的影响,指出今后海水电池用镁阳极材料的发展应在充分研究合金元素活化机理和第二相影响的基础上,研制出自腐蚀速率更小、阳极利用率更高以及比能量更大的新型镁合金阳极材料。     

贵金属阳极材料的应用与研究进展

贵金属阳极材料具有优异的电催化性能,为提高其催化活性,节能减耗减少其用量人们做了大量的研究。基于近十年来50余篇文献的分析,本文综述了贵金属阳极材料在基础化学工业的广泛应用及研究现状。展示了不同贵金属阳极的特点、发展历程和应用领域。介绍了贵金属氧化物阳极在电解水、氯碱工业、工业催化和废水处理等方面的应用进展,讨论了阳极材料的载体、控制形状、组成与物理化学特征之间的关系。对贵金属阳极材料的进一步发展及合理设计进行了展望。     

新型翼型牺牲阳极电化学性能研究

海洋钢结构保护设计中,牺牲阳极重量应当满足物料概算和初始电流密度的双重需求,当两者不同时,为达到保护要求取其大值,从而造成阳极用量过大。为了降低阳极材料的使用量,节约成本,本文拟通过提高阳极表面积来增大初始电流,并对两种不同构型的新型阳极与常规阳极进行实海试验比对,确认新型阳极的电化学性能及实际可行性。     

无机填料对高分子固体电解质与金属铝键合性能的影响

阳极键合技术是一种在MEMS封装技术中常用的一种方法,目前仅可实现玻璃与金属、玻璃与半导体材料的键合;试验采用聚氧乙烯(PEO)为基质,复配少量纳米无机填料,制备出新型的固态复合聚合物电解质作为新的阳极键合材料,通过采用DSC和XRD等分析手段研究PEO与无机填料的相互作用及导电机制,进而探讨聚合物固体电解质作为新型的封装材料在阳极键合应用中的可行性. 结果表明,无机填料的加入有效的抑制了PEO 的结晶,使得键合界面过渡层明显,键合质量良好.     

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.     

新型的治疗阿尔茨海默氏症药物(1-二甲基磷酰基-2,2,2-三氯)-乙基-1-醇烟酸醋对体外神经细胞的作用

目的: 观察本实验室合成的一种治疗阿尔茨海默氏症(AD)的药物(1-二甲基磷酰基-2, 2, 2 -三氯)-乙基^-1-醇烟酸醋(NMF),对体外培养的皮层神经细胞活性的影响以及对海人藻酸(KA)所致的神经损伤的保护作用。方法: 采用体外培养皮层神经元的方法,解剖分离 15 d胚胎小鼠皮层神经细胞, 接种于 96孔板,48 h 后加药并培养 72 h,以 MIT 法 观察 NMF 对小鼠皮层神经细胞活性的影响;同时将接种于 24 孔板的细胞预先给予 NMF,d 3 时加或不加KA处理后,以台盼蓝染色鉴别并计数死、活细胞,可得出细胞的存活率。结果: NMF 明显促进胎鼠皮层神经元活性,其中 NMF1、0. 1、10nmol·L^-1促进神经元活性增殖率分别高达 34.7%、37.4%、36. 7%, NMF 明显促进正常胎鼠皮层神经元存活卒,与对照组比较,10nmol·L^-1 NMF 对皮层神经元的存活率分别提高 39.3%、73.5%。 NMF能显著 对抗 KA 所致的神经元损伤,与 KA 损伤组相比, NMF0.1、10、10nmol·L^-1对损伤皮层神经元的保护率分别为 77.30%、80.10%、84.15%。结论: NMF 明 显促进胎鼠皮层神经元的洁性、提高正常皮层神经元,的存活卒,并能有效地保护KA所致的神经元损伤,提示 NMF 是一种很有潜力的治疗 AD 的药物。     

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).     

Three-Dimensional Growth of Coherent Ferrite in Austenite: A Molecular Dynamics Study

Coherent second phase often exhibits anisotropic morphology with specifi c orientations with respect to both the second and the matrix phases. As a key feature of microstructure, the morphology of the coherent particles is essential for understanding the second-phase strengthening eff ect in various industrial alloys. This letter reports anisotropic growth of coherent ferrite from austenite matrix in pure iron based on molecular dynamics simulation. We found that the ferrite grain tends to grow into an elongated plate-like shape, independent of its initial confi guration. The fi nal shape of the ferrite is closely related to the misfi t between the two phases, with the longest direction and the broad facet of the plate being, respectively, consistent with the best matching direction and the best matching plane calculated via the Burgers vector content(BVC) method. The strain energy calculation in the framework of Eshelby's inclusion theory verifi es that the simulated orientation of the coherent ferrite is energetically favorable. It is anticipated that the BVC method will be applicable in analysis of anisotropic growth and morphology of coherent second phase in other phase transformation systems.     

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.