快干型高固体分环氧防腐底漆的研究

目的研制高性能快干型高固体分环氧防腐底漆。方法将低黏度高活性环氧树脂和普通环氧树脂进行复配,得到可用于高固含涂料的树脂基料;通过分子结构优化设计,合成制备了以酚醛胺改性聚酰胺树脂为主体并结合柔性长链改性胺树脂复配的固化剂体系;利用复配的环氧树脂基料、自制的固化剂体系和无铬防锈颜料等组分研制了快干型高固体分环氧底漆。根据国家标准,进行了力学性能(包括柔韧性、耐冲击性和附着力)、耐环境性能(包括耐湿热、耐盐雾性能)和耐液体介质等涂层性能测试;通过考核涂层耐丁酮擦拭100次是否露底,来表征涂层的固化,采用FTIR手段,动态跟踪环氧固化过程。结果新研制的环氧涂料具有优良的力学性能和防腐性能,涂料的固含量73%,表干时间40 min,适用期8 h,耐盐雾和湿热均能达到5000 h,全面性能已达到国外现役先进材料水平,且工艺性能良好。结论以低黏度高活性环氧树脂为基体,采用酚醛与柔性长链二聚酸改性的聚酰胺固化剂,可制备高性能快干高固体分环氧防腐底漆,在飞机的防护底漆领域具有良好的应用前景。     

压载水舱高固体份环氧涂料的研究

目的提高压载水舱环氧涂料的耐阴极剥离性能。方法以双酚A型环氧树脂、酚醛环氧树脂、C9石油树脂和双酚F型环氧树脂为涂料的主要成膜树脂,采用四因素四水平的正交试验,对四种树脂的用量进行优化。固化剂采用聚酰胺固化剂和改性酚醛胺固化剂进行混合,以获得良好的物理化学性能。对涂料的颜基比及助剂进行了分析研究,以确定涂料各组分的用量。结果通过四因素四水平的正交试验,确定了涂料四种树脂的用量。当聚酰胺固化剂和改性酚醛胺固化剂的混合比例为2:1时,涂料具有较佳的抗阴极剥离性能。通过对颜填料不同颜基比(0.75:1~1.5:1)的研究,当涂料的颜基比为1:1时,涂料的耐阴极剥离性能最好。结论通过对涂料的成膜树脂、固化剂及颜基比的研究,制备的压载水舱环氧涂料具有优异的耐阴极剥离性能及良好的耐海水性、耐盐雾性及抗腐蚀蔓延性等性能,能够满足船舶压载舱的防腐需求。     

环氧导静电涂料固化剂的研究

固化剂的种类对环氧导静电涂料的各项性能影响很大,因此,固化剂的选择尤为重要.对酚醛胺T31、聚酰胺650两种固化剂进行比较试验,并对涂膜的力学性能(漆膜干燥时间、抗冲击强度、附着力、柔韧性)、导静电性能、耐油性能进行研究.结果表明:与聚酰胺650相比,酚醛胺T31配制的环氧导静电涂料具有优良的力学性能和耐油性能,且表面电阻率为108Ω,而聚酰胺650配制的涂料表面电阻率为1011Ω.因此,酚醛胺T31是环氧导静电涂料的最佳固化剂.     

腰果酚改性环氧无溶剂绝缘防水重防腐涂料在大型石油储备罐中的应用

改性腰果酚作新型固化剂制备无溶剂绝缘防水重防腐涂料,因其具有许多综合性特殊优点及其无VOC挥发,已成为大型储油罐底板内壁防腐的首选涂料.研究了新型固化剂对改性环氧树脂作用机理及其具备的特性,并通过DSC和FT-IR测试及耐盐雾试验对涂料进行部分表征.     

颜填料配比及颜料体积浓度对聚硫改性环氧涂层防腐性能的影响

目的 探究聚硫橡胶改性环氧树脂防腐涂层的颜填料最佳配比及临界颜料体积浓度.方法 首先固定颜料体积分数(PVC)为15％,采用磷酸锌作为防锈颜料、湿法绢云母粉作为体质颜料,以液态聚硫橡胶(LP3)改性环氧树脂(E51)作为涂层的基体,制备聚硫改性环氧防腐涂料,测试涂层的基本物理性能.分别利用金相显微镜和扫描电镜(SEM)...     

FEP/PPS共混涂层微观结构及其与钢基体的结合强度

以机械共混法在普通碳钢基体上制备了多种FEP/PPS共混改性防腐涂层,利用光学显微镜(OM)、电子探针(EPMA)研究了FEP/PPS共混涂层的微观结构、成分分布,采用拉伸法测定了FEP/PPS共混涂层与钢基体的结合强度,研究了共混组分PPS对复合防腐涂层结合强度的影响.结果表明,随着共混涂层中PPS组分的增加,共混涂层由典型的"海-岛结构"变为两相连续的"海-海结构",使涂层/钢基体结合强度有大幅度提高,拉断形式由涂层与基体界面光滑开裂,转变为涂层内聚开裂.     

核工业放射性固体废物包装容器防护涂料性能研究

针对用于中、低水平放射性固体废物包装容器,研究了以双酚A型环氧树脂为基料、以改性芳香胺为固化剂的防护涂层体系的性能.辐照实验、老化实验等测试结果表明,该涂料已完全达到了我国核行业有关标准中的技术要求.     

水性环氧防腐涂料的研制及应用

以自乳化水性环氧树脂及改性胺水性固化剂为成膜物,研制的水性环氧防腐涂料各项性能指标达到了溶剂型环氧防腐涂料的水平。介绍了该涂料的配方设计、生产方法、性能、用途及施工。     

聚多巴胺改性碳纳米管增强羧基丁腈橡胶动态力学性能的研究

目的 探究改性多壁碳纳米管（MWCNTs）在羧基丁腈橡胶（XNBR）中的分散性、增强橡胶基体动态力学性能及其作用机理。方法 采用多巴胺自聚合兼物理修饰的技术对MWCNTs进行表面改性处理,以增加其表面极性基团,提高其与XNBR基体的兼容性,并制备了聚多巴胺改性碳纳米管（MWCNTs-P）。采用红外光谱仪和X射线光电子能谱仪分析了改性多壁碳纳米管的表面化学状态,使用透射电子显微镜（TEM）探索了改性碳纳米管的结构演变。使用动态力学分析仪（DMA）研究了改性碳纳米管填料网络对XNBR基体的增强效果,结合复合材料断面的扫描电镜（SEM）和透射电镜（TEM）,探索了MWCNTs-P填料增强XNBR动态力学性能的作用机理。结果 调控多巴胺反应浓度实现了MWCNTs-P填料表面物理包覆层厚度从2 nm增加到4 nm。动态力学性能测试表明,MWCNTs-P填料提高了复合材料老化前后的动态力学性能。SEM测试发现,MWCNTs-1.0P-2.0wt%复合材料在老化试验后断面存在的孔洞最浅。TEM测试发现,MWCNTs-1.0P填料在XNBR基体中有更好的分散性。结论 聚多巴胺改性多壁碳纳米提高了其在羧基丁腈橡胶基体中的分散性,从而增强了复合材料老化前后的动态力学性能。     

聚苯胺防腐涂料的制备与性能研究

制备了经不同含量的聚苯胺涂覆的碳钢试样,通过腐蚀电位时效法研究腐蚀环境中的开路电压与时间的关系,利用动电位扫描研究塔菲尔曲线,检测了在质量分数为3.5%NaCl和0.1mol/L HCl溶液中的腐蚀行为.研究发现当环氧树脂脂肪胺固化剂充当溶剂首先与聚苯胺混合,再加入环氧树脂所制得的涂层比环氧树脂先与聚苯胺混合,再加入固化剂所制得的涂层的防腐性能要更好一些.研究结果表明聚苯胺涂覆的碳钢试样的防腐性能与样品中聚苯胺分散性有关,分散性越好,涂层的防腐性能越强.     

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.