铝合金用粉末涂料研究进展

粉末喷涂发源于欧洲,由于其无溶剂、无污染,近来在涂装行业得到了迅速发展,正逐渐取代溶剂型涂料涂装技术。综述了铝合金表面低温固化粉末涂料,高耐候性、耐腐蚀聚酯粉末涂料和功能型粉末涂料的研究进展。     

重防腐蚀环氧粉末涂料的研究与应用

环氧粉末涂料具有良好的耐腐蚀性和抗阴极剥离性能，本文作者郝胜勇、郑逢仁等在文中介绍了一种低温固化，具有特殊性能的重防腐蚀环氧粉末涂料的主要原料、配方、检测方法等。     

一种环氧粉末涂层的土壤腐蚀研究

采用现场埋设试件的方法,研究了环氧粉末涂层在不 同的阴极保护电位下一年的阴极剥离性能,结果表明：在环氧粉末涂料的最佳表面前处理为 喷砂处理的条件下,高温固化性能明显优于低温固化性能,其阳极输出电流随地温的升高而 增大.     

SEBF防腐耐磨涂装管在麻石除尘取代冲灰铸石管的应用

SEBF防腐耐磨涂装管在麻石除尘取代冲灰铸石管的应用(1)SEBF系列防腐耐磨粉沫涂料及涂装技术系中国科学院金属腐蚀与防护研究所开发研制的。SEBF系列高性能粉末涂料是用于钢铁重防腐的单组分、熔融结合、热固型改性环氧涂料。该种粉末涂料可在金属构件表面熔融固化形成一层厚度均匀的耐蚀耐磨涂层。它与钢铁表面具有牢固的结合力,高机械强度和耐冲击性,良好的耐蚀、耐磨性能。如抗拉强度大于90MPa,耐冲击强度大于18J,可进行车、....     

熔结环氧粉末涂料管道涂装的电晕充电和静电学原理

本文结合静电学理论,通过对熔结环氧粉末涂料管道涂装的3区模型理论的分析,清晰地阐述了熔结环氧粉末涂料喷涂时的电晕充电和静电学原理,从而对熔结环氧粉末涂料管道涂装的实践提出了一些建设性的意见。     

酚醛改性环氧粉末复合涂层介质传输与阴极剥离行为

利用静态浸泡与阴极剥离方法研究了环氧粉末涂料和酚醛改性环氧粉末涂料的耐不同介质渗透能力与抗阴极剥离性能,探讨了酚醛树脂对改性环氧粉末涂料抗蚀性的影响.结果表明,加入适量酚醛树脂的改性环氧粉末涂料在合理的固化条件下可得到90℃时的良好耐水及耐酸性,耐碱性也在一定程度上有所提高.但酚醛改性环氧粉末涂料在60℃3%NaCl溶液中的抗阴极剥离性能不如改性前的涂料.     

万能环氧重防腐涂料

江苏兰陵化工集团公司研制开发出了一种环氧重防腐涂料 ,其适用范围很广 ,该涂料具有如下特点 :1、对基材表面有很大的容忍性 ,可带锈涂装 (只需清除表面的浮锈 ) ,可在潮湿的被涂物表面上涂装 ;2、涂料底面合一 ,固体成分高 ,一次涂装干膜可达 12 5 μｍ ,属于环保型涂料 ;3、能低温固化 ,且在常温下也有足够的使用期 ;4、具有优异的物理力学性能和耐腐蚀性。该涂料由环氧树脂、改性树脂、变性酚醛胺、特重防锈颜料、填料、助剂等组成。万能环氧重防腐涂料     

从环氧-聚酯粉末涂料的固化机理看高红外技术的作用

从分子反应过程分析了环氧-聚酯粉末涂料的固化机理,说明了粉末涂料在高红外作用下快速固化的原因,从而更明确地说明了高红外技术的特殊作用.     

铸铁缸体表面粉末涂层在固化过程中脱离的原因分析

灰铸铁缸体表面粉末涂料在固化过程中出现粉末涂层剥离脱落现象,特别是在缸体的拐角处。通过铸件温度测量与固化炉的炉气温度测量,确定炉气温度高是造成粉末涂层从铸件表面剥离脱落的根本原因,调整固化炉加热温度,将固化炉一区、二区炉温控制在合适范围,避免此类问题的发生。     

工程机械钻杆与杆共线喷粉实施方案探讨

在工程机械市场竞争日益激烈的形势下,为降低生产成本,提高盈利空间,许多企业开始探索和实践粉末涂装工艺。粉末涂料具有环保、生产效率高、涂装成本低、涂层性能优异等优点。通过对钻杆与杆结构特征、涂装工艺及核心装备等方面进行研究,详细介绍了一系列工程机械钻杆与榄杆共线喷粉工艺的相关设备,并提供了相应的涂装优化方法,解决了钻杆与糙杆共线喷粉过程中复杂表面喷粉及喷粉后的固化和不同体系粉末涂装不兼容等问题。     

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。