无机硅酸锌涂料在锅炉部件中的应用

无机硅酸锌涂料是一种双组分溶剂型无机富锌硅酸盐底漆，在干膜中锌的质量比超过80％，该涂料适用于桥梁、储罐、管道、钢结构等的保护。文章总结了这种涂料用于锅炉部件时的一些涂装工艺问题。     

醇溶性无机硅酸锌底漆的疵病及原因分析

本文介绍了醇溶性无机硅酸锌底漆在施工中出现的常见疵病,并从施工环境、表面处理、施工工艺进行原因分析,并提出了解决方法。     

氧化铝增强无机硅酸锌耐蚀抗磨涂层的研究

无机硅酸锌涂层常用于大型金属结构件的重防腐保护。文中对氧化铝增强无机硅酸锌涂层进行了研究，结果表明;在试验条件下，氧化铝增强无机硅酸锌涂层的耐蚀性提高了6倍；涂层的滑动摩擦因数为0．2左右，耐磨损性能提高了3倍。氧化铝增强无机硅酸锌涂层为钢铁材料表面的防护提供了新思路和新方法，具有广阔的应用前景。     

冷冻铸造用硅酸乙酯浆料的试验研究

试验研究了冷冻铸造用硅酸乙酯水解液的水解工艺以及冷冻铸造用陶瓷浆料的制作过程,并测试了水解液和浆料的部分常温和低温性能.试验表明,以硅酸乙酯水解液作粘结剂的陶瓷浆料,可以满足冷冻铸造条件下的工艺要求.     

超细锌粉无机硅酸锌涂层的结构及耐蚀性研究

制备了3种超细锌粉作填料的无机硅酸锌涂层,用FTIR、SEM对涂层的固化机理和结构进行了研究,对3.5%NaCl溶液浸泡腐蚀后的试样表面形貌进行了观察,通过电化学试验研究了涂层的耐蚀性.结果表明,无机硅酸锌涂层的结构为:Zn粉颗粒间以Si-O-Zn聚合物网络键合,涂层与底材钢基体间是以化学键结合的微观多孔的涂层结构;涂层的耐蚀性随Zn粉颗粒度的减小而显著提高.涂层的耐蚀机理主要是电化学阴极保护作用以及腐蚀产物填塞涂层孔隙的物理屏蔽作用.     

石质文物表面二氧化硅仿生膜的探索

受石质古迹表面天然保护膜的启发,通过仿生技术,以十六烷基三甲基溴化铵(CTAB)为有机模板调控正硅酸乙酯(TEOS)的水解缩合,在青石表面制备出二氧化硅防护膜.制备出的防护膜具有优良的耐酸、耐污性能,憎水性有所增加,但仍维持其亲水的性能.用红外光谱仪对仿生膜的结构进行表征,表明其主要成分为二氧化硅.     

带无机硅酸锌车间底漆液化天然气钢结构焊接性的研究

主要针对无机硅酸锌车间底漆钢板的MAG焊接性进行研究,试验结果表明:焊缝存在气孔,未带车间底漆的气孔更高;气孔的产生与无机硅酸锌车间底漆是无关的,气孔的产生与焊接条件及工艺有关;带车间底漆试件1的焊缝根部存在未熔合,试件的弯曲试验满足规范要求;尽管未带车间底漆的试件3夏比冲击试验冲击吸收功仅为带车间底漆的50%,但所有试件的夏比V形缺口冲击试验是满足规范要求的。     

铜合金表面巯基官能有机硅溶胶-凝胶涂层中TEOS含量对其防腐性能的影响

以巯基丙基三甲氧基硅烷(MPTMS)为有机前驱体,以正硅酸四乙酯(TEOS)为无机前驱体,盐酸为催化剂,经水解-缩合反应在Cu合金H62表面制备了高固含量的有机-无机杂化溶胶-凝胶涂层。利用红外光谱仪、动态光散射粒度分析仪对涂层的化学成分和溶胶粒子的平均直径进行表征,利用SEM观察涂层的表面和截面形貌,利用拉脱法附着力测试仪和电化学工作站对涂层的附着力和耐蚀性进行表征。结果表明:TEOS的加入有利于提高涂层的热稳定性。随着TEOS含量的增加,溶胶粒子的尺寸呈上升趋势,过量的TEOS会使涂层表面和内部产生孔洞和裂纹等缺陷。当TEOS和MPTMS的摩尔比为0.6时,涂层的交联密度较大且涂层缺陷较少,涂层的耐蚀性最佳。     

TEOS含量对有机硅/SiO_2杂化涂层性能的影响

采用溶胶-凝胶法,以正硅酸乙酯(TEOS)为无机相前驱体,甲基三乙氧基硅烷(MTES)和二苯基二甲氧基硅烷(DDS)为有机相前驱体,盐酸和水为催化剂,通过水解-缩聚反应制备了不同SiO_2含量有机硅/SiO_2有机-无机杂化溶胶.经100℃烘干12 h得到有机硅/SiO_2杂化涂层.红外光谱研究表明不同TEOS含量制备的杂化材料有机、无机两相组成了强相互作用的杂化体系.采用热重分析(TGA)和耐热性试验研究不同TEOS含量有机硅/SiO_2有机-无机杂化涂层的耐热性能;采用电化学阻抗(EIS)、浸泡试验和盐雾试验研究其耐蚀性能,结果表明与未加TEOS的有机硅涂层相比,加入适量TEOS使得杂化涂层的热分解温度提高67℃,并且其耐蚀性能也得到明显提高.     

填料对无机硅酸锌涂层耐腐蚀性能的影响

利用正交试验方法确定锌粉、磷铁粉和高岭土在水性无机硅酸锌涂层中的加入量,在不同条件下评价涂层的耐腐蚀性能,通过扫描电镜(SEM)和X射线衍射仪(XRD)分析了腐蚀产物的形貌和微观结构,采用电化学方法测试了涂层的极化曲线。结果表明:添加填料的无机硅酸锌涂层具有良好的耐腐蚀性,涂层抗腐蚀介质渗透的能力提高。涂层最佳成分配比为纯锌粉加入量为固相部分总质量的70%、磷铁粉为10%、高岭土为18%和膨润土为2%。相比纯锌粉涂层,其成本降低了近30%。     

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.     

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.     

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。