430 不锈钢表面月桂酸自组装膜的探究

采用浸泡法在430不锈钢表面制备了月桂酸自组装膜,通过电化学方法、接触角测试及微观形貌分析,研究了该自组装膜在430不锈钢表面的吸附行为及缓蚀作用。研究结果表明:经过简单的浸泡,月桂酸分子能够稳定地吸附在不锈钢表面,自组装时间、组装液浓度以及基底表面前处理对组装膜的缓蚀效率有较大影响,自组装时间4 h、月桂酸浓度5 mmol/L、组装温度35℃为最佳自组装条件;基底在组装之前进行钝化处理,有利于形成致密的自组装分子膜,提高不锈钢的耐蚀性能。     

430不锈钢表面GPTMS/PFDS自组装双层膜的制备及缓蚀性能

在430不锈钢表面制备了γ-缩水甘油醚氧丙基三甲氧基硅烷(GPTMS)/全氟癸基三乙氧基硅烷(PFDS)自组装双层膜。采用傅里叶变换红外光谱、电化学测试、接触角和SEM研究了自组装膜的吸附及对不锈钢电极的缓蚀性能。结果表明,GPTMS/PFDS双层膜比GPTMS单层膜和PFDS单层膜具有更优异的抗腐蚀性能。     

谷氨酸及其衍生物在304不锈钢表面的自组装膜

采用电化学阻抗谱、极化曲线、量子化学和分子动力学,研究了谷氨酸、焦谷氨酰胺、焦谷氨酸三种自组装膜在0.5 mol/L硫酸溶液中对304不锈钢的缓蚀性能.结果表明,三种缓蚀剂均为阴极型缓蚀剂,对不锈钢具有较好的缓蚀作用;在0.02 mol/L的浓度下,随着组装时间的延长,自组装膜对不锈钢的缓蚀效率也相应增强.它们的缓蚀能力与理论EHOMO越高、能量间隙△E越低.自组装分子成键能力越强、缓蚀效率越高相一致.三种缓蚀剂分子中的氮原子、氧原子可以与铁原子形成化学键,发生化学吸附.缓蚀能力依次为:焦谷氨酸＞焦谷氨酰胺＞谷氨酸.     

K2L-SAMs对碳钢在饱和CO2油田水中的缓蚀行为与量子化学研究

利用邻氧乙酸苯甲醛缩对氨基苯磺酸钾盐席夫碱(K2L)缓蚀剂在20#碳钢表面制备自组装单分子膜(SAMs),并通过电化学方法研究缓蚀剂自组装膜的最佳组装时间;采用电化学测试技术和表面分析技术研究K2L-SAMs对碳钢在饱和CO2油田水介质中的缓蚀行为;采用密度泛函理论分析缓蚀剂分子的前线轨道、Mulliken电荷和分子静电势。结果表明:缓蚀剂在碳钢表面自组装3 h后,可以形成稳定、致密的缓蚀膜;在碳钢表面形成的K2L-SAMs能有效抑制碳钢的阴极还原过程,最高缓蚀效率达87.55%;K2L的吸附行为符合Langmuir吸附等温式,吸附机理为典型的化学吸附。量子化学计算结果表明:羧基是K2L分子的主要吸附活性区域,能与碳钢表面铁原子作用形成稳定的配位键。     

聚多巴胺自组装膜对316L不锈钢缓蚀性能的影响

通过浸泡组装法在316L不锈钢表面成功组装制得聚多巴胺自组装膜,并用动电位扫描、电化学阻抗测试、扫描电镜SEM观察及傅立叶反射红外FTIR研究了多巴胺的吸附行为及其对316L不锈钢在0.9%NaCl溶液中腐蚀行为的影响。结果表明,多巴胺发生氧化和聚合反应,并以氧原子吸附组装于试样表面;多巴胺加量较低时加速腐蚀,大于10g/L可起到缓蚀作用。组装时间24h,组装质量浓度为20g/L时可获得最佳缓蚀效果。     

自组装席夫碱缓蚀膜在油田水中对碳钢的缓蚀行为

碳钢表面自组装邻氧乙酸苯甲醛缩间氨基苯甲酸二钾席夫碱(K_2L2)缓蚀膜。采用极化曲线、电化学阻抗谱和扫描电镜研究了自组装缓蚀膜在模拟实际工作环境中对碳钢的缓蚀性能。结果表明:矿化度、温度、pH、流动状态和H_2S含量对自组装缓蚀膜在CO_2饱和油田水中的缓蚀性能具有一定的影响,但仍有较高的缓蚀率,当油田水中H_2S质量分数为200mg/L时,缓蚀率达到80.0%。     

3-氨基-1,2,4-三氮唑及3-氨基-1,2,4-三氮唑并芳香醛类希夫碱自组装膜对碳钢在0.5mol/L盐酸中的缓蚀性能研究

目的通过自组装技术在碳钢表面得到3-氨基-1,2,4-三氮唑及3种3-氨基-1,2,4-三氮唑并芳香醛类希夫碱的三种自组装膜,提高碳钢在0.5 mol/L HCl溶液中的缓蚀性能。方法采用电化学方法如电化学阻抗谱、tafel极化曲线等研究席夫碱类自组装膜在盐酸中的电化学参数,如阻抗变化、腐蚀电位、腐蚀电流。采用XPS方法对自组装膜的成分进行表征。结果计算自组装膜在盐酸溶液中的最高缓蚀效率达到92.72%,XPS测试表明自组装分子与金属原子以化学键的方式结合。结论 3-氨基-1,2,4-三氮唑及3种3-氨基-1,2,4-三氮唑并芳香醛类希夫碱自组装膜均对碳钢在盐酸中有良好的缓蚀性能,缓蚀效率的大小与分子结构有关,分子中的O、N杂原子、卤素基团、三唑环及苯环等有利于自组装膜的形成。     

咪唑类化合物自组装膜对 316 不锈钢的缓蚀作用

通过电化学阻抗谱、极化曲线和量子化学方法,研究了在0.5 mol/L的硫酸溶液中,咪唑、十二烷基咪唑、苄基咪唑、苯并咪唑四种缓蚀剂自组装膜对316不锈钢的缓蚀性能。研究结果表明:四种缓蚀剂均为阴极型缓蚀剂,对不锈钢具有较好的缓蚀作用,在1×10-3mol/L的浓度下,随着组装时间的延长,自组装膜对不锈钢的缓蚀效率也相应增强,它们的缓蚀能力主要由最高占据轨道能EHOMO的大小决定,缓蚀能力由大到小依次为苯并咪唑>十二烷基咪唑>苄基咪唑>咪唑。     

膦酸自组装膜在铝合金表面的吸附及缓蚀行为

通过自组装前后铝合金表面锌电化学沉积行为的变化研究和极化曲线测试,探讨了十四烷基膦酸自组装膜在2024和1060铝合金表面的吸附及缓蚀行为.研究结果表明:锌的初期电化学沉积优先在铝合金偏析相表面进行;偏析相表面吸附膜致密度较差,因此自组装后基体和偏析相表面之间的物化性质差异更大,从而加速锌的初期沉积;1060合金表面自...     

430不锈钢表面十四烷基膦酸自组装膜的制备与耐蚀性

用浸泡法在430不锈钢表面制备了十四烷基膦酸自组装膜,利用Fourier反射红外,动电位扫描、接触角测试、电化学阻抗及X射线光电子能谱研究了该自组装膜在430不锈钢表面的吸附行为和对点蚀电位的影响。结果表明:吸附有十四烷基膦酸分子的430不锈钢表面由亲水性转为疏水性,自组装时间为6 h时不锈钢的点蚀电位较高;氧化处理能够提高不锈钢基底的点蚀电位,且氧化处理后的不锈钢表面也能在十四烷基膦酸溶液中形成保护性的自组装膜。     

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.